January 2017 Jeff Miller Charging Infrastructure Presentation

[ted.lowe]

Wow Jeff! What a project!

7-10 days?  No rubber stamp from them? Certainly they have reviewed numerous other projects like this before? NOT

[jeffrey.miller]

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. 

[jeffrey.miller]

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
                     |
               Milbank U1740 -O 400 amp meter socket
                     |
               Meter 400 amp, 320 continuous
                     |
                     |
               Milbank U1740 -O 400 amp meter socket
                  |            |
                  |            |
         Main Panel A SquareD    Main Panel B SquareD
            QO140M200G      QO140M200G

new from             QO2150 breaker      QO2150 breaker
here down         Additional Neutral Lug   Additional Neutral Lug
                                    |                               |
                     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. 

[jeffrey.miller]

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

[ted.lowe]

That's an "extensive compliment!" Jeff 

[simon.gibson]

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.

[jeffrey.miller]

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!

[jeffrey.miller]

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.   

[jeffrey.miller]

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.

[simon.gibson]

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?

[jeffrey.miller]

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. 

[jeffrey.miller]

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

[ted.lowe]

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 

Wow... 1.5" conduit!

i heard there is a new app that works even better than a dedicated stud-finder instrument.

[jeffrey.miller]

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! 

[jeffrey.miller]

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.