HPWC Professional Installation - anyone get it?

[maddog1762]

If you do it yourself and you have a fire your insurance company may not cover your home damage.

That is the number 1 reason I had a professional electrician do my install. I am in South Carolina and it cost $800. I had a 60 foot run of #4. Picked by the electrician but it is 100 amp service. I felt it was not worth the risk of having an issue down the road. Good luck.

 

[FlasherZ]

#4 for 100A breaker? That's not to code, either.

Lots of electricians get caught up in the trap of hearing 80A and not considering the continuous load rules (which require 100A circuit).

EDIT: When you say 100-amp service, does that mean you have 100-amp service to your home and your electrician installed the wall connector at a lower current, perhaps 48A charging / 60A breaker? I re-read what you wrote and think that may be the case, just clarifying...

 

[SomeJoe7777]

Guys, FlasherZ is correct here. I'm not licensed, but I've done a lot of electrical work and was an electrician in the US military for 6 years (Navy). Continuous load rating = 80A, requires a circuit capable of 100A. That negates the use of NM 2/3. For something this high powered, I wouldn't be comfortable using NM anyway, even if it was within current ratings. I'd use #3 THHW, THWN, or THHN in EMT conduit on a 100A breaker if the run is short, or #2 if the run is long.

Don't forget also that you must look at your incoming service and make sure your total loads are within the panel, service, and main breaker capacities. (Section 220.40 and 220.82 of the NEC). Given that most home dwellings have a panel, main breaker, and service conductors sized to the minimum required for the existing circuits in the house, adding a 100A circuit will likely require at least one of these items to be upsized. If the incoming service needs to be upsized, this requires a meter pull, and that's best left to the professional licensed electricians. It may even require a new drop from the pole, which the utility will have to be involved with.

Using incorrect wiring types and forgoing load/circuit calculations is a good way to come home to smoldering embers where there used to be a garage. We're not twisting speaker wires together here. This is 20 KW of power going down those conductors; they better be installed right.

 

[breser]

I did my own HPWC install. Largely because the cost of an electrician seemed high for running the wire across an unfinished garage.

Ran the wire in PVC 1 1/2" conduit with #2 conductors and #6 ground. Running the wire was easy. Only #3 is required but #2 was more available.

Which ultimately led to the big pain of the whole thing. Getting #2 into the lugs is hard. It just barely fits.

The HPWC is very tiny inside. Getting the wires in the proper positions is a pain.

I strongly suggest finding someone with experience installing it. The price I was in quoted was fair. It was a bigger pain than I expected.

Not doing it to code will probably save you some of this pain but I can't see why you'd want to do that.

 

[Canuck]

If you do it yourself and you have a fire your insurance company may not cover your home damage.

That is the number 1 reason I had a professional electrician do my install. I am in South Carolina and it cost $800. I had a 60 foot run of #4. Picked by the electrician but it is 100 amp service. I felt it was not worth the risk of having an issue down the road. Good luck.

FAQ: Home Tesla charging infrastructure QA - Page 15

 

[LetsGoFast]

If you do it yourself and you have a fire your insurance company may not cover your home damage.

If your self-install was in compliance with the code and passed inspection, this is false 100% of the time. If it wasn't in compliance, but passed inspection I'd be very surprised if they could ever prevail. Canuck covers the case where it non-compliant well in his link.

 

[FlasherZ]

If your self-install was in compliance with the code and passed inspection, this is false 100% of the time. If it wasn't in compliance, but passed inspection I'd be very surprised if they could ever prevail. Canuck covers the case where it non-compliant well in his link.

Correct. Most states permit you to do your own non-commercial electrical work on your own home. Generally, doing it for others or on multi-family dwellings or commercial property requires you be licensed.

 

[gavine]

I would do it yourself if you have experience with electrical work. I did a similar install in my garage. Ran 2/3 NM about 35 feet to a 100 amp sub panel with two 25' 6/3 branches for 14-50 outlets. Total cost was about 450$ and it looks much better than my friend's done by an electrician as there is no conduit, all in the walls or under house. Had to have it inspected by an electrician before he would install the dedicated EV meter. He liked it so much he offered me a job!
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Is your 2/3 in a wall with insulation? Is that allowable?

 

[David.85D]

I will DIY just about anything, but decided the install of a 20KW Tesla HPWC was best left to a pro. It’s a hell of a lot of juice. Vaporizing metal sort of thing if you screw it up...

My electrician ran wires in steel conduit. I asked him to use 2 gauge even though he felt 3 gauge was allowed. I wanted the lower temperature rise of the bigger wire and a bit of future proofing if a higher power charger comes available.

There were state and local incentives available for EV charging when I got mine and those all required copies of the permits, which is another reason to do it the right way.