FVEAA Forums
Public Communications => Meeting Presentations => Topic started by: jeffrey.miller on January 22, 2017, 01:49:31 AM
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I am going to post the presentation in text in here so it is searchable by future people (like me).
This is the first of what is likely to be many presentations on the topic of the serious charging infrastructure build I am doing at my house.
Six steps
Plan
Acquire materials (at a discount)
Upgrade house service to 400 A (320 A cont.)
Install conduit to garage and panels
Install conduit and disconnects for stations
Build and install stations
Continuous vs rated, rated*.8=continuous=charging rate
Power Needs
I would like to charge 2 Tesla’s 75A and 2 cars 35A
- Off peak and as fast as possible (real time pricing)
Chargers are more efficient at full power
Cheap rates only last so long each night
Four family members, and friends who drive EV’s
Three car garage and one outside at the end of the garage
Considering Electrically heated driveway
- 150+ amps at 240V
Puts demand way beyond existing 200A service
Cheaper to put in stuff now compared to rebuilding later
Can use the power to charge cars when it isn’t snowing
Requirements
75+75+35+35 =220 amps continuous!
I would like to just park where convenient
All chargers the same 75 amp capability
This makes electrician head’s explode
They do load calculations and assume
All 4 100 A circuits are in use 100% continuous
80 A cont *4 =320A = the complete service of the house!
House also has E-Oven and E-AC, everything else big is NatGas
While I won’t have four Tesla’s all charging normally
I need to prevent bad things, and convince inspector all is well
There need to be limits
- Charging stations can be set manually
Disconnects can have smaller fuses
JuiceBox and new Tesla charging stations can agree on a current that doesn’t break things (inside brand only)
Not perfect, as they can’t account for other large loads
like a heated driveway
Scouring the internet I have found enough to make me believe I can get a system working with OpenEVSE
That is another presentation…
Just set them all to 50A while I work out the details
How am I going to do this?
- Breaker boxes above 225A that work for home service don’t seem to exist
Normal implementation is to put in 400A meter and then run 2 200A main breaker panels from it.
My service is on the other end of the house in the basement
Put second panel in garage direct from meter?
Put in a meter box with breakers?
Put another meter on the garage itself?
Service upgrade time!
- In my case I am adding a second 200 A panel just like the existing one in my basement and using a plain meter base without breakers
This requires the main breakers be very close to the meter
I also plan to move the E-Oven to the new panel to balance the load when AC and oven are on.
Only one problem, how I am going to run all of those charging stations when I have my service split in two halves which are in the basement?
- Plural sub panels
Two of them, one off of each main panel in the basement to the garage.
Gain access to more power than a single 200A panel could provide, so long as I can convince inspectors
I have 150, 125 and 100 amp breakers to run to the subs, and will run the biggest I can get approved.
The sub panels are 225A capable 42 slot monsters
The slots aren’t required, but space to turn the big wire for the charging is very nice (they were cheap too)
- Someone in the audience has just realized:
My job of balancing load across charging stations has just gotten harder
I lose the ability to truly park anything anywhere
However:
I add enough total power that I am not losing sleep
Originally the best I could hope for was 100A continuous shared across four stations
Now I am looking at 240A continuous, with each pair of charging stations sharing 120A continuous
Two Tesla’s on one sub panel would limit them to 60A each, not ideal, but not worth chasing
Charging station connectivity
- With OpenEVSE I can connect conduit many ways and with large wire size, but what if I need to change a charging stations in five years?
So instead of wiring from the breaker to the charging station I decided to put in a disconnect
There are more than a few places that this is a requirement
This will be right at the charging station and for added safety I bought fused disconnects
I can run any size charging station by changing the fuses
Proper fuses are more likely to break DC than an AC circuit breaker, they are also faster
Could DC back feed in to the charging station?
In theory if the charger in the car breaks in just the wrong way it could connect the DC battery pack directly the 100 Amp AC circuit feeding the charging station. Depending on the relative voltage and exactly how it went wrong we are either going to be backfeeding DC in to the grid, or doing some very quick charge, discharge cycles to the battery pack. These are both bad, backfeeding DC in to the grid could damage many things in the rest of my house, and since circuit breakers are designed to break AC current only it is likely that it will try to open, only to be fused shut / catch fire by the high current DC voltage flowing through it. This will result in further damage. The resistance of the grid is possibly enough to keep the EV fuses intact as they can provide lots of amps for the car to drive. It is possible that the fuse for charging is different than the controller, we hope so in this situation. Putting fast blow high DC current breaking fuses in line offers additional protection to my house, car, and family. Possibly the reputation of EV's across the world. Before you say that could never happen, lightning strikes routinely cause exactly these types of scenarios in computer power supplies. I also had a car battery charger that died just like this during a storm. When I took it apart the transistor was shorted through, and the 1 amp fuse was predictably blown. Scaling up for a standard 12V car battery to a traction battery, and the circuit breaker is the only external protection as most installations. I will be putting surge protection in the breaker boxes, but they are no guarantee, and since they are parallel, not in line with the car, they can't even blow open to prevent a surge.
Maybe I am paranoid, but compared to the money spent of the rest of this stuff this has the best chance of stopping anything truly bad from happening for a reasonable cost.
Materials
Wire sizing
Determining wire gauge is easy, except it isn’t really.
I have bought for 150A, and 100A connections
Wire insulation is THHN which is 90C rated
https://lugsdirect.com/WireCurrentAmpacitiesNEC-Table-301-16.htm
So can I carry 150A on #1? The NEC310.15(B)(16) table says I can
No, the breakers only allow 75C load rating, and requires a minimum of 75C rated wire
http://www2.schneider-electric.com/resources/sites/SCHNEIDER_ELECTRIC/content/live/FAQS/175000/FA175147/en_US/Wire%20Terminations%200110DB9901R2-02.pdf
So why is THHN the most readily available?
Temperature Derating, my garage is above the ambient temp which is allowed to run 75C wire at full rated current
What I need wire
1/0 copper THHN for 150A breaker to subpanel 300 ft
#6 bare copper earth ground main to sub run 100 ft
#3 copper THHN for 100A breaker to disconnect 450 ft
#8 bare copper earth ground from sub to disconnect 150 ft
I also got a deal on some #4 copper so I picked that up to cover the ground to the mains and the ground rod for the main panel upgrade 25 ft
I could use the #4 to run to 50A outlets if I want
Ft lengths are what I calculated I needed
Conduit
Now that we know what wire is going where, we can calculate the conduit size.
http://conduitfillcalculator.com/
They don’t include bare wire for ground, so I have used to THHN to estimate that.
For runs with 3 or more wires, you have to be below 40%.
I am using Electrical Metal Tubing (EMT) as it is thinner and lighter than Rigid Metal Conduit (RMC)
By picking 3 #3 and 1 #8, we get 38% fill on 1 inch EMT
By picking 3 1/0 and 1 #6, we get 29% fill on 1.5 inch EMT
Dropping to 1.25 inch EMT yields 40.5% fill
The runs from the basement to the garage will be challenging enough to pull the wire through that I don’t want to make it harder by trying to go with a borderline fill ratio
There are adjustments that can be made for the total amount of bends in a run of conduit
No more than 360 degrees of bends in any one cable pull. You can insert a pull box to break the pull in more than one part.
My basement to garage run will have about 300 degrees of bends, so having a 29% fill will help make that pull much easier
The sub panel to disconnect pulls will only have about 200 degrees so higher fill worries me less
What I bought
4 100A 240V 1ph 3wire fused safety disconnects, I chose SquareD D223N, D223NRB for outdoor
2 150A+ 240V 1ph 3wire main lug breaker boxes, I chose the 225A SquareD 42 slot as they were cheaper than anything else I found
Additional main panel 200A 240V 1ph 3wire, I chose a matching one with what I already have
Meter base 400A 240V 1ph 3wire, 2 sets of lugs, I chose Milbank U1748-O for underground wire
Comed has an approved meter base list, this is one of the few 400A on it, and it seems to be the most common
I kept the same brand and type of breaker boxes so that I could move breakers around at will
SquareD QO series in my case, and they are readily available at more than your local store
Nothing better than retail on Craigslist after monitoring for 6 months
Bought them on Ebay for deep discounts compared to other sources
QO are going through a product changeover which the old models are phasing out, but the feature they added doesn’t matter for my purpose
I paid 89 for the 225A and 95 for the 200A panels
Free shipping
I spent 6 months monitoring Craigslist, ebay and Amazon for SquareD QO breakers 100A and above.
100A breakers 2 pole, $31 avg cost delivered
125A breakers 2 pole, $26 avg cost delivered
150A breakers 2 pole, $175 avg cost delivered
200A Main breaker, $45 delivered
The 150A breakers are much more expensive and they also consume four slots in the box instead of two
I went for the SquareD D223N (3) indoor and D223NRB (1) outdoor
Nothing good local for 3 months on Craigslist
Ebay yielded results on New or close enough to new units to meet my needs,
To my door costs 151.57 for all 3 D223N, and 65.24 for the D223NRB
300ft of 1/0 THHN craigslist $205
1000ft of #3 THHN craigslist $400
250ft of #6 ground craigslist $80
500ft of #8 ground craigslist $100
161ft of #4 THHN craigslist $45
$830 in copper cable!
I have serious excess in #3/8 which will get resold
Retail for that is about $1600, and that is shopping around for it.
Thoughts on Juicebox
I was talking to JuiceBox and their 75A charging station has a 6 gauge whip to connect to the service provided by a 100A breaker.
They were quite confident in their solution and suggested using a junction box to connect to larger wire.
You can’t wire it direct to a breaker, or even a service disconnect (which was my plan) as breakers and service disconnects are only rated for 75 C wire, and this would be 90C+ to run 100A service through a #6 wire.
I wasn’t impressed as their documentation didn’t point out this detail or reinforce the junction box suggestion as the requirement that it is.
An electrician should know this but why take that chance.
I reorganized this content compared to my presentation order, and added some written notes to fill in for my verbal stuff. Feel free to ask questions.
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Conduit size links
https://sizes.com/materials/conduit_EMT.htm
http://www.home4c.com/conduit.htm
Milbank 400 A meter box
https://www.gordonelectricsupply.com/index~path~product~part~35522~ds~mfr~process~search~qdx~0~ID~%2CMilbank%2CMeter.Sockets...Com.Ed
https://images.tradeservice.com/9ETBOIYK8205G6UU/ATTACHMENTS/DIR100131/MILBANE05090_1_2.pdf
Someone asked about AFCI GFCI protection
http://www.homedepot.com/p/Leviton-20-Amp-125-Volt-AFCI-GFCI-Dual-Function-Outlet-White-002-AGTR2-00W/300049855
http://www.homedepot.com/p/Leviton-15-Amp-125-Volt-AFCI-GFCI-Dual-Function-Outlet-White-R02-AGTR1-0KW/206804820
You can also get that same protection in a Circuit breaker.
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If you ever wondered what the number "10K" or "22K" means on your circuit break this forum page seems to answer that question quite well
http://forums.mikeholt.com/showthread.php?t=56030
Post #6 by friebel
"
To: mgnh, I would recommend that you contact the Cooper Bussman Company to get their book on "SPD Selecting Protective Devices, Based on The 2002 NEC. Their phone number is 636-394-2877. They will send one to you free of charge. If you were close by I have several in my possession.
This book will explain all that you would ever want to know about AIC, and Selective Fuse Co-ordination.
Now to answer your question, "What does AIC mean?"
If you took a bar and shorted out the secondary of the transformer that feeds your facility, that would be determined to be the Available Fault Current. Suppose that this current would be 50,000 amperes. Any fuse down stream of that fault would have to have an interrupting rating of at least 50,000 amperes.
Today, if you would look on the barrel of the fuse, you would find a rating saying 200ka or 300ka. Meaning 200,000 or 300,000 amperes.
Now, as you go further downstream from the 50,000 amp fault, the fault current will decrease because of the resistance of the wiring in the circuit. For example, generally at a lighting panel, the circuit breakers are in the range of 5000 AIC or 10,000 AIC.
But bottom-line, get the book that I suggested, and it will answer all of your questions.
"
As another poster on that forum notes, it is often referred to AIR not AIC on some breakers.
Passing 22,000 amps through a 10K breaker is likely to result in a fire or small explosion, just like trying to break 400 volts DC with a 48 volt rated fuse!
At my house my main breaker is a "22k" but all of the other breakers in my panel are "10k" because the wire size has high enough resistance to prevent more than 10,000 amps from passing through them. I would guess that few people would bother trying to locate higher rated breakers but me being me, most the breakers I have purchased are 22K breakers. I got them for little to no premium over the 10K breakers so I got the better ones. Are they required? For the breakers heading to the subpanels this could be a legitimate concern, the wire is very large and low resistance. For the #3 wire heading to the charging station, this is a bit less of a concern, but the price was right, so those breakers are protected against catastrophic failure in the case of a low resistance short. So for me if the price is equivalent get the better breaker :)
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A gentleman from ABB gave us a presentation on how the spark inside a breaker is quenched...
Also note that breakers are rated for branch circuit protection or supplementary protection. UL Added this in 2005:
http://www.ul.com/wp-content/uploads/2014/04/ul_OvercurrentProtectionSupplementary.pdf
Branch Circuit UL 489 - Protects wire and cable against Overload and Short Circuit
or
Supplementary UL1077 - Provides additional equipment protection where branch circuit protection is already provided or not required AND Not suitable for the protection of branch circuit conductors
You'd be surprised how often the supplementary is (mis)used!!!
This might make useful reading although Mike Holt is the 'go to'
http://library.automationdirect.com/branch-vs-supplementary-circuit-protection/
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The electrician hasn't been able to come out and do the service upgrade yet. :(
I have been tempted on several occasions to do it myself, but I have shown restraint.
What I am trying to avoid is running the conduit for the farther charging stations in the summer time. I have to run them through the garage attic, which is confined, south facing, and red brick, in the summer. Since that is one of the last steps of this project I was hoping to get started about the new year so I could be running that conduit in March, before it gets hot up there. Best laid plans and all that.
On the downside, I was talking to member Mark about his Leaf, and he mentioned all of this charging stuff netted him a nice rebate, but that program is over. Since one of the stipulations was you had to use an external electrician I would have paid more, but got some back, not sure I would come out ahead though.
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Jeff can u call my Shop 847-842-9543
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The electrician has me on his calendar for April 8th for the service upgrade.
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The electrician didn't want to get permits for the work and decided not to do the job. I do want permits pulled for a service upgrade, it isn't an easy undo and disabling it kills power to the house making the family unhappy.
Back to shopping for electricians.
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I have located an electrician for the service upgrade. His company frequently does service upgrades and he brings out three people to run through everything in one day. I don't have a date yet, but assuming obtaining the permit doesn't take forever, it will be in the month of May.
I met with another electrician that I will probably work with on future phases of this, but as he works alone he couldn't get through the job in a single day. He was willing to put temp power in place but the process was going to take longer and potentially cost as much if not more money. He also doesn't do as many in a year as the bigger company, so I get the benefit of that experience.
On the Comed front of the in ground wire, I called their 800 number and asked what would be required from ComEd to get this service upgrade going cost wise. The agent opened a case with the Crystal Lake city ComEd rep. That rep called me a couple of hours later and told me the wire in the ground was the proper size for 400 already and that they would inspect it once the city had completed their inspection. Comed would then send a tech out to replace the meter. According to the Comed person the meter itself wouldn't fit in the new base properly.
No electrician I have spoken to expects that to be a problem, but they have a hard time mentioning recent jobs specifically upgrading 200 to 400. Such is life as an early adopter.
I will provide more details about the job and the contractor once the job in complete.
The most amusing discussions have come from the 150 Amp breakers and the fact that not only do they exist, that I have two of them in my possession. If you recall they are MUCH larger than a normal 2 pole breaker and the shock and then amusement when these guys hold these massive things for the first time is quite hilarious.
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Another detail that has come from my discussions around this is that the local inspector matters. Every town has their own inspector and those people have differing opinions on topics. Speaking to the inspector before a big job like this is certainly a good idea as there are details that are smaller than what is covered in any code book. This can cause rework on jobs because the inspector doesn't like how it has been done. One of the factors in me selecting the larger group was that he does this same job in many towns and he takes the most stringent requirements from each of the towns and applies it to every service upgrade. This limits the chances for rework and helps him be more successful. These are often very small details down to choosing between two perfectly acceptable fittings.
Getting buy in from the local inspector is an important step in any project that you want pass on the first inspection.
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I have a building permit for the first phase (upgrade to 400A service) and an electrician scheduled to perform the work Thursday the 11th of May. They are planning to complete work in a single day with 3 people. Assuming I have power the night of the 11th I will post if they succeeded. :)
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Great to hear Jeff. May the force be removed and returned to you in that single day! ;D
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Power is back on, they are tidying up the last of the stuff.
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Thanks for the support Friday night everyone.
I will try to post some photos from the upgrade.
Also noteworthy if I hadn't gotten a permit I would have been left with a 200Amp smart meter, compared to the green 400Amp smart meter that was installed when Comed came out.
Next stop is making up drawing and plans for the two subpanels.
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I just submitted the building permit for the rest of the work. I decided I would rather have the whole thing reviewed as one massive piece of work, then piecemeal. What I did do is ask for the disconnects to be considered outlets and have the permitting process stop there. The goal is what charging station I plug in is up to me to do at my leisure. I observed that there are no 100 amp outlets and as such this was my best substitute. Also I noted that I recognized the limitations of the service is lower than the total of the potential demand, and I explained why I wanted that and the various ways I can control it.
As part of the documentation I measured the current flow through the mains in each panel under a high load condition and I have a pretty good amount of breathing room as my higher leg of the service was drawing 45 amps. That leaves me at least 35 amps for things that weren't on at that moment in time. I will probably look through what is connected where and move a couple of breakers around to balance my load a bit more, my red side is pulling double the amps of the black side in both boxes. Evening that out a bit would be good, but that is analysis for another day.
On top of the four 100 amp disconnects I also added two 50 amp outlets. With those in place I would have the ability to charge six cars at an average of 40 amps each. It would also provide flexibility for various conversion EV's that don't have J1772.
Now I wait 7 to 10 days for the inspector to respond.
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Wow Jeff! What a project!
7-10 days? No rubber stamp from them? Certainly they have reviewed numerous other projects like this before? NOT :)
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I haven't heard back yet. I might try to stop by tomorrow and ask about it if I don't hear from them first. I dropped it off in the afternoon so technically 10 business days doesn't expire until Monday. The service upgrade permit was issued in three days, but the electrician was following up aggressively.
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Here is the text from the supplemental documentation I submitted with my application:
Summary
Add two 150 amp sub-panels in the garage with two 50 amp outlets and four 100 amp capable disconnects from those two panels.
Detailed description
I want to install four locations to install charging stations, and I want each location capable of delivery 80 amps continuous. I don’t want to change breakers and wiring each time I decide to park a car in a different spot, so I would like to install fused disconnects in each location, and then install a charging station along with proper fuses at my leisure. I view this similar to “plugging in” a charging station to a RV outlet, but using the disconnects as outlets due to the lack of 100 amp outlets on the market.
My house was recently upgraded to 400 amp service in preparation for the delivery of large continuous service to the garage for car charging. The goal is to provide up to 240 amps continuous to electric cars. Based on 80% utilization I need 300 amp service to the garage to achieve this. The house has 400 amp service but that is split between two panels. I will install one 150 amp 240V breaker (Square D QO2150) in each main panel on the upper left side. From each main panel I will run three 1/0 copper THHN jacketed wires along with a 6 gauge bare copper ground through 1.5 inch EMT to one garage sub-panel (SquareD QO142L225G 225amp main lugs purchased at a good price) per main panel. Each sub-panel will have the screw removed that connects Earth to Neutral. I will install the dedicated earth ground bar. This configuration provides a total of 300 amp / 240 amp continuous to the garage for distribution to charging stations.
Once the two sub-panels are installed I will install two SquareD QO2100 breakers in each sub-panel. From each breaker and neutral lug, I will install three 3 awg copper THHN and one 8 awg bare copper ground. These will run through 1 inch EMT to the four fused disconnects. The fused disconnects are SquareD D223N, except the one that is planned to be outside, which is a D223NRB. Two disconnects will be connected to each sub panel, but the size of the fuses and the current limit of the charging stations will be set to maintain a maximum of 120 amps per sub panel.
Most EV’s draw between 15 and 34 amps at 220 volts. The large demand cars are the Tesla’s, and their standard chargers only consume 48 amps. The high end Tesla chargers can consume between 72 and 80 amps. With this in mind I want the flexibility of putting a 80 amp Tesla in a specific bay without changing anything ahead of the fused disconnect. I just want to change fuses, and charging station. Since most cars draw below 40 amps, I could place two of the largest consuming Tesla’s and two normal cars on charge at one time, as long as they are spread properly across the panels. My two kids will be driving in a few years and they will have electric cars. All of my cars from now on will plug in, and with a three car garage and one charging on the end of the garage outside to support the fourth car I have a relatively easy way to configure this house to support my whole family driving electric.
You might wonder why I want to charge all four at once. I am using ComEd RRTP (residential real time power) and only want to charge when power rates are low. Since there are only so many hours in a day when that is the case I need to maximize the power I can deliver to the cars during those hours. On top of that, car chargers get less efficient when running at less than maximum current. I want to get as many kwh into the car battery for my kwh delivered across the meter. I am also an active member in the FVEAA (Fox Valley Electric Auto Association) and as such many of my friend drive EV’s, and I want to provide charging when they come visit. This is less challenging as the Tesla owners won’t need to charge, but all of the Leaf, iMiev, Smart Four2 EV, and custom built EV owners will. None of those cars draw the high currents of a Tesla, so to maximize my charging flexibility I would also like to install one 50 amp outlet per sub-panel. The 50 amp outlets would have at least 6awg main conductors, and a 8 awg bare ground. My plan is to keep them very close to their sub panel, and I will calculate the proper conduit for the wire I am using based on NEC table 1 in Chapter 9 (40% fill maximum). I happen to have 4 awg in abundance and most 50 amp outlets support it, so I might use that with a 1 inch conduit, but I may procure 6 awg and use ¾ inch conduit. These 50 amps outlets would be rarely used but available for those various home built EV’s that don’t have EV standard J1772 connectivity. All charging stations I would consider installing can have their max current limited through their software and I would apply those software limits when more than a few of my friends come to visit. The lower range cars that need to charge, max out at 30 amps, at 220v. By providing the four normal stations and two outlets I will only be drawing 180 amps total continuous with each car being an average of 30 amps. Many charging stations have a process in their software to adjust multiple charing stations to align with the total current available to them, and I will be pursuing this functionality.
This design achieves my goal of a highly flexible and useful charging infrastructure to power the future of personal transportation for my family.
I do not intend to have the charging stations installed at the completion of this permit. I am requesting that you treat the disconnects as outlets so that I can purchase and install the actual charging stations over time as I need them. I want to install all of the conduit and cables in one go to save cutting open the various walls over and over again.
Current measured at the main panel with washing machine, water heater blower, AC and, oven running. All other normal loads, lighting, fish tank, computers running normal loads.
Panel A Red 15
Panel A Black 12
Panel B Red 30
Panel B Black 19.5
Based on the above loads the red side is at 45 amps and is the limiting factor with the way the loads are distributed. Even if we count all running loads as part of our continuous load 45 amps it leaves 35 amps for other continuous loads under full load charging. The house has about double the power it needs to run all large loads at the same time. This is confirmed by the data from the smart power meter which shows our max hours being between 8 and 9 kw.
Existing large electric loads
single AC unit (connected to Panel B) 15 Amps measured
electric oven (connected to Panel A) 9 Amps measured
Smaller loads
full size fridge freezer (connected to Panel B)
wine fridge (connected to Panel B)
small freezer (connected to Panel A)
5 desktop computers drawing 500 continuous and up to 1kw peak (connected to Panel A)
lighting (all LED) (spread out)
Gas appliances (limited impact)
Drier
Range
Furnace
Drawing
*Note from Jeff, this drawing printed out better than it displays here*
ComEd service conductors
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Milbank U1740 -O 400 amp meter socket
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Meter 400 amp, 320 continuous
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Milbank U1740 -O 400 amp meter socket
| |
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Main Panel A SquareD Main Panel B SquareD
QO140M200G QO140M200G
new from QO2150 breaker QO2150 breaker
here down Additional Neutral Lug Additional Neutral Lug
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3 1/0 THHN Copper 3 1/0 THHN Copper
#6 awg bare ground #6 awg bare ground
1.5 inch EMT 29% fill ratio 1.5 inch EMT 29% fill ratio
| |
50A outlet1-qo250--- Sub-Panel A in garage Sub-Panel B in garage ---qo250 - 50A outlet2
______SquareD QO142L225G SquareD QO142L225G ________________
QO2100 breaker QO2100 breaker QO2100 breaker QO2100 breaker
| | | |
| | | |
3 #3awg THHN copper 3 #3awg THHN copper 3 #3awg THHN copper 3 #3awg THHN copper
#8 bare copper ground #8 bare copper ground #8 bare copper ground #8 bare copper ground
1 inch EMT 38% fill 1 inch EMT 38% fill 1 inch EMT 38% fill 1 inch EMT 38% fill
| | | |
Disconnect 1 Disconnect 2 Disconnect 3 Disconnect 4
SquareD SquareD SquareD SquareD
D223N D223N D223N D223NRB Outdoor
watertight fittings
where exposed to rain
Conduit will be supported within 3 feet of the terminations to panels, any other junction boxes, and also every ten feet.
All cables will be marked Red White Black or Green near their connection points.
Fuses also offer an additional layer of protection for the rare case that high voltage DC backfeeds into the charging station. The fuses are designed to break DC and quench the continuous arc, where circuit breakers are not.
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I contacted the permit office and due to sickness, vacation, storm damage, and my "extensive application" they haven't been able to review it yet. It was even said that it was "complex". They promised that they would review it Monday when one of the electrically smart guys was back. It was only four pages :)
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That's an "extensive compliment!" Jeff :D
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Ahhh, I guess they haven't encountered this type of installation ... yet.
Maybe we could put together a package for them to help them with future permit requests of this type?
My guess is they'd appreciate the help.
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The permit is in! The person doing the review was the backup to the main electrical guy, so I might be able to shift things somewhat by speaking to the primary electrical inspector when he returns from vacation.
The reviewer didn't bite on my idea that they should certify this setup and never hear from me again. They want me to permit each charging station that is wired to a disconnect, and provide a load calculation each time I add a charging station, where I was hoping to deal with that all in one pass. I may still get that done under this permit, but his opinion is I would need to have a spec sheet for the charging stations and put that in to the load calculation and provide them that.
There are at least two ways to do load calcs, but since I can measure actual loads I was hoping to avoid that, as they can work out unfavorably compared to modern loads. The load calcs assume all incandescent light bulbs for lighting. I can't imagine my house with all incandescent lighting, my power bill would be massive (this house has at least 119 light bulbs totaling about 11kw the way it was when I moved in). I have seen discussion along the lines of using actual loads compared to calculated, but I don't yet know for certain if I can get that approved here.
The lighting in this place used to cost twice as much to run as the AC compressor and oven combined!
Good news, I can get started!
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The inspector also advised that I needed to follow 210.8 GFI, but said "as required". Speaking to him, he wasn't certain if 50A 240 volt outlets in the garage require GFI, and volunteered to look it up. It says as required so I volunteered to look it up later. We are on NEC 2005 here, and conveniently someone posted the PDF of that. http://dsps.wi.gov/Documents/Industry%20Services/Forms/Elevator/HistoricalCodes/2005%20NEC.pdf
210.8 only calls out 125 volt single phase 15 or 20 amp outlets in various places including the garage. So I am fine for putting in the 50 amp outlets without GFI.
Probably tomorrow I will tackle the load calculation section of the NEC 2005 code to see if there is something about using actual vs calculated.
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I couldn't help myself, so I dug into it.
Just found this in the code. Since I have a smart meter, and can go back and look at the stats from it for the entire time I have had it, I might be able to use that data. If not I guess I get to set up that current monitoring system I have always wanted :) to collect data over 30 days.
My previous measurements show that 125% of my current load is not an issue.
NEC code:
220.87 Determining Existing Loads. The calculation of a
feeder or service load for existing installations shall be
permitted to use actual maximum demand to determine the
existing load under all of the following conditions:
(1) The maximum demand data is available for a I-year
period.
Exception: If the maximum demand data for a 1-year period
is not available, the calculated load shall be permitted
to be based on the maximum demand (measure of average
power demand over a 15-minute period) continuously recorded
over a minimum 30-day period using a recording
ammeter or power meter connected to the highest loaded
phase of the feeder or service, based on the initial loading
at the start of the recording. The recording shall reflect the
maximum demand of the feeder or service by being taken
when the building or space is occupied and shall include by
measurement or calculation the larger of the heating or
cooling equipment load, and other loads that may be periodic
in nature due to seasonal or similar conditions.
(2) The maximum demand at 125 percent plus the new
load does not exceed the ampacity of the feeder or
rating of the service.
(3) The feeder has overcurrent protection in accordance
with 240.4, and the service has overload protection in
accordance with 230.90.
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Hi!
Maybe the lighting circuits are all run with #14 on 15A breakers. If you demonstrate that they can all be run on a 10A; maybe that will reduce load. But the actual usage will demonstrate what is needed. The main thing is to ensure the conductors are protected against overload.
Also the EVSE stations are set to deliver to the vehicle what is available as opposed to tripping breakers when they call for all 50A!.
If you include cut sheets for all the EVSE equipment, that would imply that is the equipment being installed and they'd want to see it. But if all the EVSE is 'plugged in', they wouldn't need to see that. WRT to GFCI, The range and clothes dryers don't call for it. Presumably the EVSE falls into the same UL listing - Maybe a question to some of the EVSE vendors - They might shed some light on what is current code?
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The code of 210.8 is very clear that a 240V 50A outlet in the garage doesn't require GFCI, only 125 volt, 15 or 20 amp outlets require it.
EVSE incorporates GFCI in all cases that I am aware of, so no real risk to the actual humans.
So every time I install a charging station I would have to perform a load calculation to show that enough is available, both at the mains and the branch. Most likely in that scenario I would just install and permit all at once. The view is that this permit is just for the build leading up to a final design which will be submitted, reviewed, and approved at a future date. This is what I am trying to avoid, but will take up when the lead guy is back and caught up on his work.
One of the good things that they have accepted is that I am installing 150 AMP breakers to provide service to the subpanels. I was initially worried that they might challenge this decision, but that wasn't a problem. So I am happy about that.
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Step 0.1 is complete!
0.1: Fix the Spitfire's brakes, charge the batteries and relocate it to the other end of the garage. It had a warning sensor that physically detected differential pressure between the front and rear brake circuits. Since the idiot light was previously removed anyway, I removed the device from the car because it was leaking brake fluid almost as fast as I could pour it in. It has a set of orings inside that I could have replaced and so forth, but since it was an extraneous part, I replaced it with brake line couplers that fit the lines going into the old device. That warning device was one of the few original looking parts in the braking system, everything else looks new. Nothing was permanently altered as part of this so this is easily reversed if I ever wish to rebuild the part and reinstall it.
I now have easy access to the wall that I intend to put the big stuff in.
Various 1.5inch conduit couplings arrived recently for the runs to the subpanels.
Next stop is to cut open the garage drywall, drill down into the basement and confirm my theory is correct about the space for conduit.
I won't have this done for tomorrow's meeting :(
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Great to hear of your progress Jeff!
i am entertained that you, like a computer guy, start your numbering with zero.
i'm glad your charging project lead to some Spitfire work too :D
Wow... 1.5" conduit!
i heard there is a new app that works even better than a dedicated stud-finder instrument.
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Cut hole for the first breaker box and all was really good, in fact I had lots of space right to left. Cut the next hole and discovered why. The stud between the two boxes is slightly to far to the left giving more an excess of room for one box and a shortage for the other. Less than 1/4 of an inch, just enough that I need to go pick up another tool to shave it down a touch. Such is life.
Holes into the basement are both drilled and looking good. Path from the breaker boxes to the holes are looking good.
Bought 1.5 inch conduit, and tossed it into the conduit bender I bought for the job in the winter, and discovered the key difference between EMT and Rigid benders. The one I bought was for rigid and allows the slightly narrower EMT to crush. I checked Craigslist and no benders for sale at this time for this size, which is to bad because a couple of months ago someone was selling a bunch of them. Rigid is way more expensive than EMT (thin wall) so I have already purchased a pile of angles and what not to do the job without it. It would have been nice, but that is life.
I still have a valid 1 inch bender for the really big job of running the conduit to the charging stations.
Such is life!
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It has been a busy couple of months with work, but I still have managed to do some work. I have to run the first conduit complete and then pull the cable (I will explain with pictures in a future presentation) and that conduit is all the way to the box (not mounted to the sub panel yet). The second run is as far as it can go until the first cable is pulled.
So far so good, it would have been nice to have a bender but I have bought pieces that meet my needs. I did sell the bender for what I paid for it, so at least I didn't lose money on that transaction.
Before I mount the box I need to drill holes for the 50 amp outlets and insulate the wall behind the box to some degree.
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The wall is insulated and the first sub-panel, and 50 amp outlet box are mounted and have conduit to them. With the help of my DAUGHTER! we pulled the worst of the first run, the 30 or so feet from the main to the first pull through corner. This has 135 degrees of bends in it, the rest have less. Hopefully tomorrow I can get the pull complete to the subpanel and start connecting things.
Then it would be time to start on the second sub panel. (which has conduit most of the way already)
I am definitely going to have to lube those more complex runs for the garage, it was all we could do to move through 135 degrees of bend, and this run was a much lower fill ratio than the garage will be.
Progress continues.
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Wow that run sounds very complicated! Glad you got it done and with your DAUGHTER's help :) :) :)
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I don't plan to use something like this but I am unusual.
https://www.tindie.com/products/nsayer/j1772-hydra/
It is the backbone of a dual head charging station, or a dual head setup for a single charging station. For example if we wanted to have two J1772 at Yellow Box we could plug one of these in during the meeting and it would allow two people to share that station. It balances the load and all that good stuff.
I heard about the above little project while I was speaking with the man behind TucsonEV about 75amp J1772 charging cables which is is willing to build and sell to me for a reasonable price! I was very happy to speak with him and we had a good discussion. With that item figured out the only other unusual item I need to procure for the OpenEVSE charging stations is a larger contactor / relay. THe openevse store used to have them on there but they are no longer listed. I am following up on that topic.
The cable pull is stalled due to a lack of muscle around the house, it is hung up less than 2 feet from the subpanel. Looking for help if anyone is motivated to stop by and yank on a rope for me.
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I have used my bigger ladder, my chain hoist and a large steel bar to create a derrick system to pull the wire the last few feet up into the box. I have pulled the earth ground and one of the hots in so far. Two more to go and the source will be in both the main and the sub panel ready to connect.
As discussed on the other thread this is more relevant due to the pending purchase of a vehicle that actually plugs in.
I also ordered an OpenEVSE charging station and one of their 90 amp relays. I went ahead and ordered the full kit including the cable so the 90 amp relay won't stay in this one, but I wanted to just see how it all goes together before I buy a bunch more.
Also for future reference, the 90 amp contactor
https://store.openevse.com/products/packard-c390c-90a-contactor-208-240vac-coil-50-60hz
75 amp J1772 cable is going to be sourced from
Rush Dougherty
TucsonEV
520 240 7493
www.TucsonEV.com
I must admit I didn't work on anything in January, to cold, and didn't want to leave the car outside. Now that it is "warming up" I don't mind as much getting back at it. Plus the EV motivation is stronger now.
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I have used my bigger ladder, my chain hoist and a large steel bar to create a derrick system to pull the wire the last few feet up into the box. I have pulled the earth ground and one of the hots in so far. Two more to go and the source will be in both the main and the sub panel ready to connect.
Nice Jeff! Clever innovation to make up for staff shortages :)
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I don't plan to use something like this but I am unusual.
https://www.tindie.com/products/nsayer/j1772-hydra/
You do or you don't plan on using the hydra?
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Never heard of the hydra, but wow, what a cool product!
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At my house I shouldn't need it.
It might be something that we build and deploy during meetings at the Yellow Box. Any interest? With that device in place the Dakota could charge at 2.5KW and leave 3.5KW for someone else. Since many cars charge at 3KW this could work out nicely.
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At my house I shouldn't need it.
Ok, i understand, just wanted to make sure.
It might be something that we build and deploy during meetings at the Yellow Box. Any interest? With that device in place the Dakota could charge at 2.5KW and leave 3.5KW for someone else. Since many cars charge at 3KW this could work out nicely.
Yes definitely (or variant). i was just thinking about a "product" that could be used to spontaneously share a single EVSE. It would have a single J1772 inlet and two J1772 cables. Unplug an EV, plug into "hydra-like" inlet, plug both EVs in and bingo. May want the other EV owner's permission up front :)
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I can build one of those - I can build panels - send me the info!
I'd like to get right on that! I think there was a link on OpenEVSE?
Also we should talk about all the communications options for these!
Simon
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For sure Simon, let's discuss the details first and then design and build (a beta version)!
A great initial beta test can be at the CCC. My EV (dakota) wants up to 2.5kW and another EV can have the rest, up to a total of 6.6kW i think for the Clipper Creek?
i haven't looked at the Hydra in any detail yet... i'm interested in knowing if it looks at the pilot signal from the EVSE to determine the total power available, and then negotiates and allocates the appropriate power to the two EVs. Or is it always 50/50?
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I will almost certainly be able to donate the contactors needed for this project. I will know more next week for sure after I do the first build.
The charging station kits from OPENEVSE come with contactors which I replace with the larger units. It doesn't make $ense to buy the parts separately to avoid buying the contactor, so I will have 4 or so extra contactors.
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Excellent, thanks Jeff! Portable EVSE sharing devices can increase the FVEAA's outreach when we need charging. i personally will need charging very often at outreach EVents due to the limited size of the Dakota's pack. Having one onboard to use at the CCC each month will give me much less range anxiety too.
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I received the full OpenEVSE kit and the 90A contactor yesterday. The 90A contactor is close to the size of the entire OpenEVSE enclosure! I guess I won't be putting that contactor in that enclosure. This specific unit was just planned to be a normal unit and I bought the contactor "early" to see how it would all go together in their enclosure, and the answer is it won't.
Looking for enclosure options now.
On the wiring front I have the cables from the first Main panel to the first sub panel pulled through now. I also have connected them at the Main, progress! It does look slightly weird to see both mains with covers and no wires hanging out.
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https://www.budind.com/check-stock2.shtml?product=NF-6614
This may be my favorite manufacturer site ever!
They don't sell direct, but they do list all the major retailers, what their price and stock levels are, for any enclosure you click on. They also let you filter by interior or exterior dimensions. I may not buy from them in the end, but not because of their web design.
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https://www.evseadapters.com/products/portable-chademo-quick-charger
This is a pretty neat piece of hardware, expensive, but neat. 10KW max, which is a bunch for an older iMiev or Leaf but not interesting for a Tesla. I could possibly see mobile "EV Rescue" companies using these devices.
In news closer to home the first sub panel is connected to it's main. Next step is to wire the first 50 amp outlet, probably tonight.
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OpenEVSE is up and running!
Much faster than the ole 110 outlet.
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Great Jeff! Does/will yours have network integration (an option i think)?
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It has the WIFI module in it so I have been using that to schedule charging and check on things. Last night I charged starting at 2AM.
Beyond that it supports https://data.openevse.com/emoncms and others as partially documented here https://openevse.dozuki.com/Guide/OpenEVSE+WiFi+%28Beta%29/14
It also supports API calls so I have long term plans to automate things based on those calls. Long term I want to slow, or stop, charging when the price of power spikes.
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It has the WIFI module in it so I have been using that to schedule charging and check on things. Last night I charged starting at 2AM.
Great stuff Jeff! This kinda of stuff really charges me up :) i think i missed it... what are you charging?
It also supports API calls so I have long term plans to automate things based on those calls. Long term I want to slow, or stop, charging when the price of power spikes.
That would be awesome if it's doable. Seems the power companies make it hard to get real-time data in a usable form. Only screenscrapping possible now? Else, smart people will start to actively "game" the real-time pricing programs and render them less beneficial for all?
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https://hourlypricing.comed.com/hp-api/
Comed have several options on API's, and they are reasonably documented at that URL. The trick for residential real time pricing is you get billed for the average for the hour, however at the beginning of that hour you don't know what the ending average will be. So if you charge heavily through the first 30 minutes, at an average of 1.0, and then the second thirty minutes of the hour average 30.0, even if I stop charging 30 minutes in, I get charged 15.0 for what charging I did. I have emailed Comed about this, and they said "that is our plan".
That sort of wild fluctuation doesn't happen as much in the middle of the night, but in the summer from 11 to 12 during the day it sure does!
As far as gaming real time pricing, it is an hourly average, which makes it tough to game.
Also if you reduce load when prices skyrocket, you aren't gaming the system, you are doing what the power company wants, reducing demand in response to higher prices. Gaming the system would require us to team up with large industrial consumers to tweak their demand for our benefit. I have a tough time seeing how that would work though.
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Great response, thank you Jeff!!!
i'm glad to see they now (finally) offer APIs... i'll definitely take a look at that in detail soon!
Yes the "hourly granularity" makes it hard to optimize individual usages. i guess, it's a bit like gambling at a casino... the more skillful players will win more often, not every time. Over a course of a night (granularity) they will do better than the average player.
So.. some strategies come to mind on how to take advantage of (game) current ComEd policies. Note ComEd can and will change their policies to always favor themselves, like a casino has, especially when more people start to "take advantage".
Some ideas to optimize financial and environmental benefits via hourly-pricing, EVs and Solar PV:
- sign-up for hourly pricing with ComEd
- charge EVs/PHEVs only at night, especially in the Summer
- be very careful of AC use in the day time Summer hours - pre-cool house by turning the thermostat down to 60 until 7am, wear a sweater even if necessary to save some $ like a "5 mile jacket" :)
- don't bake or cook a lot during peak Summer months
- timeshift all electric-intensive tasks, like an electric clothes dryer or hottub usage to night time (off peak times)
- install a good sized (but not oversized) PV system that especially cranks out the valuable/expensive electricity during the peak Summer days - if the system is too large, it will generate more power per month than is used. NO CREDIT is paid via Net Metering on a bill month to month. Zero net usage for a month is the best that can be achieved financially. Any extra power generated above net zero will be given away freely to ComEd, which would be good for climate-change-Karma-points i guess.
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Here is an API query (via HTTPS) for the last 5 minute price (at the time of this posting - 3/17/18 1:23p)
https://hourlypricing.comed.com/api?type=5minutefeed&datestart=201803171320&dateend=201803171320 (https://hourlypricing.comed.com/api?type=5minutefeed&datestart=201803171320&dateend=201803171320)
Results in JSON:
[{"millisUTC":"1521310800000","price":"2.6"}]
aka 2.6 cents/ kwh
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Right now this is my favorite enclosure. They do make a Stainless steel version, but I am not interested in parting with an additional $800 just to make it look prettier. Besides, all the other electrical stuff is grey. The only way it could be better is if it had a window, but I can cut some holes in it. I will continue the hunt for something like this but with a window
https://www.budind.com/pdf/hb3731.pdf
SNB-3743
https://www.budind.com/check-stock2.shtml?product=SNB-3743
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I didn't call for reinforcements because I was lazy. On a positive note I did get some work done. I finished the conduit from the second main to the second sub panel. I made some decent progress in destroying the drywall in the garage and making it ugly with conduit (that is what my wife thinks of this phase of the project). I have more destruction to do though!
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:D :D :D :D
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Thanks for the updates Jeff! If you need reinforcements Saturday’s work well for me most of the time.
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I worked today on the conduit runs and made some excellent progress. I am not going to be done before the P85+ comes home, but at least the conduit running across the ceiling is done now. Next up is to cut out even more drywall and install the second 50 Amp plug and the first recessed disconnect. I have the conduit to the location of the two "mid" disconnects, and I will just need to bend the "kick" in those two short pieces and mount the disconnects. At some point I will need to move the Spitfire out of the way so I can get a ladder in that corner and cut open the drywall to finish the last 6 feet of that conduit run. I am glad to have the garage attic work done (all I can do before moving the Spitfire) before it got warm outside.
More details and pictures on Friday!
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https://www.mouser.com/ProductDetail/Bud-Industries/NBD-10469/?qs=CzuyTOUYZuSyeuu2mwym%2FQ%3D%3D
I am thinking this might be my enclosure to put 80 AMP charging stations in. It has a clear lid so I can put the display inside without cutting any large holes in the door. We can see my wiring (YUCK) and check for large sparks or flames that might indicate an issue!
It is made out of ABS but I don't think I have a problem with that or not.
Thoughts?
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If the charger is in the garage, why do you need a box to enclose it?
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I am building my own charging stations out of components. If I skipped the box I would have live wires hanging in free air. Seems less than ideal :)
I would use the OpenEVSE enclosure, but it is to small to assemble an 80 amp charging station into. I am using their normal electronics with an uprated cable and contactor to handle the higher currents. Their normal electronics support up to 80 amps in firmware so that isn't an issue.
https://store.openevse.com/collections/all/components to check out their component list.
https://store.openevse.com/collections/openevse/products/openevse-international-combo-openevse-v3
This component kit is almost perfect for me, except it contains the contactor I don't need as I am using the larger one.
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Another thing I ran across very recently
https://electrek.co/2018/02/09/ev-charging-credit-extended-2018/
Federal EV charging equipment credit has been retroactively renewed for any equipment brought online in 2017. If you installed stations last year, you might want to check your taxes.
Form 8911
https://www.irs.gov/pub/irs-pdf/f8911.pdf
Instructions
https://www.irs.gov/pub/irs-pdf/i8911.pdf
30%, max of $1000. If you have already filed and you put in a bunch of equipment last year it might be worth amending your filings which can be done for many months still.
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Work session May 5th 9:00 AM start at 199 Midway Ct Crystal Lake, lunch provided. If possible, let me know you are coming so I can plan sufficient food.
At this point three of four disconnects are mounted and ready for cable. I should have the fourth one done by the weekend.
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Hi Jeff,
Thanks, i may be able to attend this work session. What is the topic/tasks planned? i'm sorry i missed your talk in the 2nd half of the April meeting where you probably mentioned this.
Thanks,
ted
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I forgot to mention what we are doing!
Pulling cable from the subpanels to the disconnects in the garage. As the subpanels are easily turned off there will be no electrocution danger in this project.
This involves several work streams that can happen in parallel:
Run a fish tape through the conduit from one end to the other
Mark fish tape for length so we can get the right length wire after we pull it out
Tape rope onto fish tape and pull rope through, also put some lube into conduit
Tie rope down to prevent it falling out
Roll out fish tape for measuring against actual cable
Unroll actual cable and cut to length
Mark each length of cable a color to denote hot, hot, or neutral by wrapping a few feet of each end with colored electrical tape
Bring cut cables to one end of the rope and attach to the rope
Team of two people start pushing/pulling cable into conduit, also apply some lube to the cable
If it gets difficult, utilize mechanical advantage as required
There are five things to run cable to, two are close by but the other three are long and complicated runs of conduit.
My goal is to get the cable in place, I have no problem stripping and connecting it all by myself but doing all of the above physical tasks alone takes a long time.
110 car charging is available for at least two vehicles. 240v J1772 is also available while work is not being performed (this is less than ideal).
As you can see from the above task list there are many tasks that are easy to run in parallel. This isn't really possible with running conduit which is very serial by it's nature.
I look forward to seeing some of you Saturday, please RSVP and include food preferences so I can be properly prepared.
Already planning for Vegan with my standard Vegan Chili and will expand on that as I learn more about who is coming.
Thanks,
Jeff
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Can't wait to help although I'll be a little late as I have a morning obligation until 10:30 in West Chicago
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We rocked the work on Saturday and pulled all of the cable before lunch! I was hugely impressed with what we accomplished. I spent the evening stripping and connecting and finished connecting everything for the left subpanel. I will work through the right one tomorrow night and hopefully get it done so I can have the inspection late this week.
Thanks for the help everyone!
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Inspector should be here in a few minutes.
While reviewing NEC I found the old link to the 2005 code was dead so I found a new one
http://www.northchicago.org/vertical/sites/%7B892BE042-FCA9-4ADD-99D5-E4FC8D1104BD%7D/uploads/2005_National_Electric_Code_(NEC).pdf
Suggest a local copy if you need the 2005 version in case they delete it too.
Will report back with results.
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Inspection passed!
They were very happy with my work.
We discussed my next permit, their biggest concern is that it works for the next owner without overloading, I will have to figure out how to make them happy while retaining the flexibility I desire. I think software could be good enough, but it would be best if it was in the charging station, will have to figure that out.
At the very least I now have two 50 amp outlets I can charge my EV's on, which gets the job done.
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Congrats on passing your first inspection Jeff!
i'm not sure what you mean by "overloading". Drawing too much power from all the charging spots at once?
Isn't that what the circuit breakers are for?
Did you get the next permit yet? If not, do they need some NEC detail to issue the permit first? Seems there is some "winging it" going on... this scenario probably hasn't happened too many times on a residence in Crystal Lake or in the whole USA either :)
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Article 625 covers charging stations. A good read for everyone honestly.
As you likely recall I have two main panels, feeding two subpanels with 120 amps continuous each. The two charging stations connected to each subpanel are capable of providing 80 amps each which would cause an overload condition of 40 amps above the continuous rating of the circuit powering that panel. Somehow I have to limit the total current per panel to 120 amps in a way that is robust enough to pass on to the next owner of this house while assuming the next owner doesn't have my level of understanding. There are several possible approaches, from the easy, just set them all to 60A and forget about it, to the extreme, software based controller that runs the whole house while monitoring the price of power and adjusting demand to minimize cost. There are a vast number of ways to skin this cat, so I will be figuring out my approach and then writing it up.
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As I mentioned in the meeting the other day I am looking for fast blow fuses for the disconnects, and I want the highest DC voltage rating along with the highest DC current interrupt rating (AIC, see many posts ago for that). First a reference on what the different classifications mean:
https://www.fusesunlimited.com/glossary.aspx
The fuses that came with some of the units were type RK5, which is a slow blow type, good for motors. I need the opposite, a fast blow to protect the equipment, wire, and possibly my house. Type RK1 is what is appropriate for my purpose as it is designed to stop current flow, not just sever the connection and hope for the best.
I also mentioned I expected to pay a bunch of money in fuses. The ones I had seen previously were over $100 per fuse, and I need 8. After spending some time digging I have located a fuse model that sells for a fair bit less than the others, at some vendors.
Ferraz Shawmut A2K100R, also Mersen A2K100R
Unlike the More common Bussman or Littlefuse brands that I can't find for below 100, these seem to retail for under $40 in at least two cases.
https://www.allfuses.com/a2k100r
https://www.pacificcoastbreaker.com/a2k100r-100a-250v-class-rk1-fast-acting.html
I haven't ordered any yet but will be soon and will update who I went with and if they stole my money or not :)
There were also some of these for sale on Ebay, but they weren't that much cheaper for something that could be easily counter-fit.
That fuse is also rated at 250 VDC unlike the Littlefuse version that I had found that was only rated at 125VDC, while costing 1/3rd the money.
In other somewhat related news re-reading the NEC 625.34 in the 2005 book and noted that when dealing with EVSE greater than 60 amps it's disconnect has to be able to be "locked in the open position", and needs to be "accessible", or close to the charging station.
"locked open position" means that you can apply a padlock to the disconnect to prevent someone from turning it back on. This requirement is quite common in industrial settings where equipment maintenance teams can turn off equipment, and lock it, so they can work on it without worrying about someone turning it back on. This is a feature in the disconnects I have installed.
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I didn't answer the overload question thoroughly enough for my liking.
As discussed above I have two panels that can deliver 120 amps continuous, but they are supplied by 150 amp breakers. The 80% rule applies to any continuous load like EV charging. In this case the 150 amp breaker would not trip very quickly at 160 amps, and at 150 amps it should never trip. 150 amps is a 30 amp overload from the continuous rating of the circuit feeding that panel. It will likely do this for a long time without nuisance tripping, but eventually the breaker will start to overheat and fail. This is the scenario they are trying to make sure I prevent. I need to create a way to "set and forget" the charging stations so that they never overload the 120 amp continuous rating of the 150 amp circuit. There is a bunch of room between 120 and that 150 breaker tripping and they want to make sure that isn't abused.
I also want to make sure it isn't abused, as it leads to things being potentially unsafe.
To me the gold standard is to have the charging stations read the total current coming into their box and limit it to 120. This would require current sensors in the sub panel, a way of sending that current data to each of the EVSE connected to that sub panel, and the EVSE being smart enough to figure out when to reduce and by how much. This could potentially include the two EVSE that could be plugged into the 50 Amp outlets.
The above is a very tall order, and it not only has to work while I live here, but forever more! Forever more implies physical cables with some form of communication running through them to negotiate. There are no standard in this area. The closest thing around is the Tesla High Power Wall Connector (their 80 amp EVSE). Two of those can share a single circuit (according to the install manual) however they aren't set up to share a large service that isn't larger than each of them can deliver. In other words, you set in the units an amperage of the circuit they are sharing with a max of 100 (80 delivered), however in my case I would need to set them to 150 (120 continuous) but that isn't an option.
If Tesla provided that ability off the shelf I may have bought them and switched the ends over to J1772. (there is even a service that does this for a fee) That doesn't answer my whole laundry list of other things I want to do, but it would be easy to justify to the inspectors.
Hopefully that clears things up.
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Great explanation, thanks Jeff! i remain very curious to see what your solution is.
Re: the lockable disconnect
i find that interesting about EVSEs, because the same requirement is in section 690 for solar PV systems. Within 6' of the ground, on the outside of the building, lockable "off" disconnect. Maybe for a slightly different reason though, to let utility linemen make sure that a distributed energy generation system is not feeding the lines while they work on them.
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I am thinking my solution (temporary) will be to install two big charging stations (I have all the parts to build two) and assume two small ones, and submit that as an initial permit. That gets me two 80 amp full time and two 40 amp full time stations which is exactly what my limit is. Once I sort out the controls for the other two I will permit and install them and implement some form of overarching control system to manage all of them.
In related news, the temp tags arrived for the Tesla today.
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I filed the permit application with the city for the two big charging stations. I expect no issues with that from them.
"Permit application addendum May 22nd 2018
As you likely recall from my recent work I have four disconnects that can support four 80 amp charging stations, along with two 50 amp outlets to support two 40 amp charging stations.
I don’t yet have a method ready to deploy that automatically manages the power split between these potential six stations, however if I only install two 80 amp charging stations, one per sub panel, I cannot exceed the total 120 amps continuous available. This will allow me to fully utilize my Tesla and not create any risk of exceeding the circuit capacity.
Once I have a system in place to manage the total current draw across the full complement of stations then I will return and put a permit in place to do the last two and discuss with you the details of that system. That functionality requires some serious time and thought to make it a robust solution that both fits my needs and a less technical future owner. I have some good concepts on this, just need to build and validate them. In the mean time I can deploy two at full rate and have no concern of overloading anything. "
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I did have to jump through a couple of hoops, especially provide an updated drawing, but I got the permit today to install the first two big charging stations. This along with the two 50 amp outlets will bring me up to four stations.
I had a good discussion with the city electric plan guy and explained some of the bigger picture things I am doing and he said he would be looking at some of these concepts as people submit paperwork in the future. Also he really likes my ASCI art diagrams!
I imagine in a week or so I will have the easy one installed. The hard one, which will be recessed into the wall, will be a bit longer as I sort out the mounting for it.
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First station is installed. It is surface mounted, so fairly easy compared to the other one which will be recessed into the wall. A bit of metal working went into the backer plate to make the contactor fit in the enclosure.
When I run it at 80 amps it seems to drop the line voltage to the car by by about 5 volts, compared to when charging at only 10 amps. In theory that is 400 watts turning into heat to get energy to the car. Voltage drop at those sorts of current levels isn't surprising, but I suppose I will be checking to make sure it is not all happening in one spot. 400 watts of loss on all of the lines and connections between the transformer and my car isn't concerning, but if most of that is concentrated in a single connection then that would be concerning. 400 watts assumes that the transformer and it's upstream feed is completely stable when I add my 19kw load which is likely not to be the case. I was testing this when the outside temp was above 90 degrees, so good chance the upstream lines, transformer, and grid weren't all that happy. I will do some measurements tomorrow and confirm that none of my connections are going to get hot due to excessive voltage drop.
Fuses and breakers both create heat and since I have three breakers, and a set of fuses in the path, those could account for most of the heat being generated when I charge at 80 amps.
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80 amps is HUUUUUUUUGE compared to myy 13
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You can measure the voltage wrt to ground or neutral at various points along the way when its drawing 80 amps. where the biggest drop occurs is where the culprit lies! Depends how sensitive your meter is, how many decimal places! But, you are right, a large voltage drop in one spot would indicate a bad connection...
Simon
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A brief check this morning and I saw the same voltage on both panels, and since the only common point for those two panels is the meter box and the comed stuff, I am no longer worried. That voltage was fairly close to what the car was showing (it is a cheap meter).
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I gave a short update on my charging system at the last meeting. The performance of this set up is impressive to me (the car and the kit I have installed working together).
One of the big things is to make sure you use wire ferrules, or some other crimp on connector, on the flexible cables going from the charging station to the car. If you just try to shove fine stranded wire into a screw terminal you could have serious problems.
http://www2.schneider-electric.com/resources/sites/SCHNEIDER_ELECTRIC/content/live/FAQS/126000/FA126881/en_US/Fine%20Stranded%20Wire%200515DB0301.pdf
The OpenEVSE Advanced kit comes with pre crimped ring terminals that fit the included contactor, so this isn't an issue with that kit as much. The standard kit comes with ferrules. Since I am designing my own to a large degree I had to provide my own ferrules.
https://www.amazon.com/gp/product/B01I9E0X0A
https://www.amazon.com/gp/product/B01I7X480E (I cut the red pieces off as I was using them on earth ground)
https://www.amazon.com/gp/product/B01I9DUNM4 (these weren't in stock when I was buying the 8ga ones)
https://www.amazon.com/gp/product/B01I93KA90
If anyone is tackling a project like this, let me know, I have quite a few extras.
I didn't speak specifically about the cable gland, but it is a nice metal unit, it costs a bit more than the plastic ones, but not THAT much more.
https://www.amazon.com/gp/product/B071VT8PW8
I also showed the metal channels that will get mounted to the studs with some means of mounting the charging station to it. This will allow the two charging stations to be recessed into the wall a few inches. This makes it easier to walk through the garage and also not as likely to hit them with the cars.
I had those metal plates bent out of galvanized 1/16th inch steel (16 gauge) and each cost me $32. I could have left it not galvanized, or thinner gauge, but for the cost of $32 each (about half labor half materials) I was happy to buy the heavy material. The shop that did this was
https://adamssteelservice.com/
I dropped off the design of what I needed one afternoon and it was done the next day.
Enclosure
https://www.budind.com/pdf/hb10449.pdf
NBD-10469 with the clear cover, and it's matching plate
I bought them from Mouser
https://www.mouser.com/ProductDetail/Bud-Industries/NBD-10469/?qs=CzuyTOUYZuSyeuu2mwym%2FQ%3D%3D
https://www.mouser.com/ProductDetail/Bud-Industries/NBX-10996?qs=sGAEpiMZZMvJyyQy4slOTqesa7FilqJ1HkYnPTuw%252bZo%3d
The rest of the parts came from OpenEVSE, but I believe I have linked them all before.
I did buy the J1772 cables from quick charge power.
Fuses came from https://www.pacificcoastbreaker.com/a2k100r-100a-250v-class-rk1-fast-acting.html
Additionally I will report that I can hear the hum from the current flowing through the electrical system in many parts of my house, including my master bathroom, when the car is charging. My master bathroom is directly above the conduit running to my car charging station. It is quieter in the basement as that is a larger breaker, but the box in the garage hums somewhat louder as there are 80 amps flowing through a 100 amp breaker there. It isn't excessively loud like something is broken, just the soft hum of power flowing.
There were questions we have to defer to another day around charging costs specifically related to the Comed Residential Real time Pricing, and also the centralized control of all potential charging stations to keep them from over loading the 120 amps continuous per sub panel I have available. Those are two complete topics to dive into very deeply at some future point.
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I forgot a detail
I also used:
"MOV V275LA20AP (red disk Metal Oxide Varistor) to reduce chatter noise created by the bouncing contactor coil."
(quote courtesy of OpenEVSE build guide)
purchased at Mouser
I also used a torque wrench to tighten the large connections on the contactor to the proper spec. I have used my torque wrenches extensively in this project.
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Finally, some CHEAP electricity!
Last night my car charged for 40 minutes and took in 12.8kwh.
During that period of time the price of electricity was -2.4 cents, before delivery charges of course. I paid about 46 cents to "fill up" my Tesla early this morning. I have only seen negative prices a few times since I have had my Tesla. It was very common last summer but it seems Exelon is getting better at not giving away money.
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The city approved those two charging stations :)
On to the next two.
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My last "presentation" wasn't exactly a presentation but instead a live demo of the capabilities combined with a build session. We did do the tour of the supporting infrastructure once everything had wrapped up with the builds but I think the cold weather discouraged some people from staying that long. Between the last build I did, and the current one OpenEVSE has updated the design in a few small but fantastic ways. I won't go into the full details at this point, but my assembly time to go from a pile of parts to a wired backer plate ready for the garage dropped by at least half. On top of that it was easier to understand and all the instructions were better consolidated especially in regards to the WIFI module. I also didn't have to use or provide any additional wire in my build (DC coil contactors might still require a piece of wire) so it was much easier to just crimp ends on than dealing with the long list of tiny terminal blocks. I find it interesting that it took them this long to get this far into a design improvement as OpenEVSE builds and sells these stations to end users also, the labor had to be killing them.
Updated product page
https://store.openevse.com/products/openevse-plus-v4-universal-charging-station-controller
Direct link to excellent connection diagram.
https://github.com/OpenEVSE/OpenEVSE_PLUS/blob/master/OpenEVSE_PLUS_v5/OpenEVSE_v5.pdf
Those of you that have built these will probably notice how much easier this makes it to figure out what is what.
We had 2x Rav4, 2x Volt, and the S10 all simultaneously charging. I know Chris was pulling between 24 and 30 amps most of the night, the Rav's were pulling 40 each and the Volts are good for 15 so that equals at least 134 amps at some point there. Early in the evening before the fifth station came online we would have been drawing about 120. Not enough to cause Comed to show up at our event, but a good evening of charging and enough to get everyone back home from sticks of Crystal Lake. The sixth station did work, I saw a few amps of current flow before we killed it due to the noise the coil in the contactor was making. Ever so briefly we were charging six cars.
I sent Tony Williams of Quick Charge Power a nice thank you note for overnighting the cables to my door so we could do those builds that evening and get those online.
In related news, I no longer know of any current production Full EV that charges at less than 6KW, and with the Volt finally switching over to the higher rate charger 32 amps just like the Bolt even the new versions of those will charge much faster. Regrettably the 2019 Outlander PHEV in the US retains the slow charger.
As someone pointed out, Friday night was the evidence to prove my theory that a house could reasonably require 4 charging stations, and potentially more in the case of guests coming over from long distances. Some day I might be the holiday destination of choice for my family, not just because the food is good, but because it is easy to charge and get back home afterwards. :)
My journey of building charging stuff at my house is almost over (they physical part anyway), others are picking up the torch though. I know Simon is putting in substantial pieces of kit right now, and Mike W keeps saying he needs to do it. Other members are starting to get serious and seeing my build has provided some ideas. I am excited to see what comes next in the home charging space in the FVEAA.
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I learned something new today.
https://www.tesla.com/support/home-charging-installation/onboard-charger
The Model 3 Long Range has a 48 amp charger (not 40 as originally reported), and the Mid Range and Short Range have a 32 amp charger (not 30 as originally reported).
I am happy to hear this, more charging rate is a good thing in these cars. 48 amps is enough to receive 10kw on 208 volt service, which is a nice option for destination chargers.
I have also heard that the 2019 Volt will finally have a 7.2kw (32 amp guesstimate) in it.
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20% off Juice box charging stations, today only!
https://evcharging.enelx.com/store/residential