Model S - HPWC (High Power Wall Connector)

[tga]

Can I legally wire the HPWC myself?

Depends on your jurisdiction. Only your local electrical inspector/building department can answer.

I live in NH, where homeowners can do their own work (if you live in the house). You need to pull a permit and get it inspected. I used to live in MA, which has a similar law, but a lot of MA towns refuse to grant permits to homeowners, essentially banning homeowner electrical work (so a lot gets done without permits or inspections).

 

[Maximapolak]

Will this wire work for the HPWC? (60, 50, or 40 amp breaker?) Is the 10 AWG ground good enough?

 

[xsi123]

Will this wire work for the HPWC? (60, 50, or 40 amp breaker?) Is the 10 AWG ground good enough?

If you use 60 amps breaker you need #4 AWG wires. Also, make sure your service can support 60 amps.

For 50 or 40 amps breaker #6 AWG is fine.

Not sure about the ground cable

 

[tga]

Unless you are running underground, use regular NM-B (non-metallic) interior wire, not UF-B (underground feeder, more expensive). Make sure you set the amp selector correctly in the HPWC.

 

[Maximapolak]

Unless you are running underground, use regular NM-B (non-metallic) interior wire, not UF-B (underground feeder, more expensive). Make sure you set the amp selector correctly in the HPWC.

I have a detached garage so I have to run the cable outside. I'm assuming I can't use the NM-B for that.

 

[tga]

I have a detached garage so I have to run the cable outside. I'm assuming I can't use the NM-B for that.

Missed that. Forget what I said before - you need UF to run underground to the garage - can't use ordinary NM romex.

 

[David29]

Can I legally wire the HPWC myself?

That depends upon your jurisdiction. In my experience, some electrical inspectors allow it and some do not. Some states allow homeowners to do their own electrical work, subject to inspection, others don't.

 

[Racerx22b]

In my experience, if you do it yourself expect the inspector to give it full "cavity" search. You better have everything done absolutely perfect or even better than perfect. I just had solar installed and the inspector was on site for a total of 4mins to do the inspection. He didn't even open up the meter box to check the main tie in. Never got on the roof or even in my attic. What a joke. My power company came to install the net meter and said the tie in should've never passed inspection.

I bet if I did the solar install myself everything would've been torn apart.

 

[Yinn]

Can I legally wire the HPWC myself?

NJ allows installation yourself with proper permits and inspection. Some local jurisdictions will be more detailed than others and might require a detailed electrical drawing to accompany your permit application.

Fill one of these out: http://www.nj.gov/dca/divisions/codes/forms/pdf_ucc_stdforms/ucc_f120_elec.pdf
and contact your town's construction department.

The 6/2 UFB with 10awg ground is rated for 55amps, but NEC requires a minimum 20% overhead; so that's utilization at ~44amps.
I generally like to give myself even more room and size up when wiring. So in the above situation if I was aiming for 44amps, I would do a 4/2 with a 8 ground instead. That's just me being paranoid though.

I had the same thought initially on doing it myself and did a ton of reading. These threads are useful:
FAQ: Home Tesla charging infrastructure Q&A
Chart of Wiring/Breaker/Conduit for Tesla Wall Connector

After pricing out everything and getting a couple of quotes; I decided it just wasn't worth trying to do myself.

 

[cmd_keen]

DIY here...

 

[Maximapolak]

Hmm...got my 24' HPWC today. I'm still debating on installing it or the NEMA 14-50 because I'm only going to be running the 40A from the 50A breaker.

 

[MorrisonHiker]

Hmm...got my HPWC today. I'm still debating on installing it or the NEMA 14-50 because I'm only going to be running the 40A from the 50A breaker.

There are many posts which discuss attaching a 14-50 cable to the HPWC. You can limit it to 40 amps and it would allow you to keep the UMC with the car.

 

[Maximapolak]

There are many posts which discuss attaching a 14-50 cable to the HPWC. You can limit it to 40 amps and it would allow you to keep the UMC with the car.

Right, but I can just sell the HPWC and save the $600.

 

[MorrisonHiker]

Right, but I can just sell the HPWC and save the $600.

That would work too. We use two UMCs in my garage.

When there's a third Tesla, we'll probably consider going the load-balanced HPWC route. Until then, the UMCs work fine.

 

[Peter_M]

Right, but I can just sell the HPWC and save the $600.

Your choice, but the HPWC has some good benefits even at 40A. It has just one plug connection (handle to car) vs. 3 for the UMC (handle to car, UMC to adaptor, adaptor to outlet). Plug connections are where most wear and tear happens and where poor connections leading to overheating are most likely. Also, if you have only one UMC, either you leave it at home and potentially get stuck if you need it on the road or you buy another one to keep in the car, which costs the same as the HPWC.

 

[Don85D]

In my experience, if you do it yourself expect the inspector to give it full "cavity" search. You better have everything done absolutely perfect or even better than perfect. I just had solar installed and the inspector was on site for a total of 4mins to do the inspection. He didn't even open up the meter box to check the main tie in. Never got on the roof or even in my attic. What a joke. My power company came to install the net meter and said the tie in should've never passed inspection.

I bet if I did the solar install myself everything would've been torn apart.

We installed a solar array ourselves as owners of our house and both the Electrical Safety Authority ( permit and inspection) plus the local power utility made life difficult. The power utility doesn't like small solar arrays feeding their grid as they are big power guys. Their requirements had to be met for connection and that meant changing to a dual ganged meter at extra cost. Their engineer said that it would take approval from seven departments to get my request for exemption passed even though he agreed two meters would work and be safe. The safety inspector deals with his buddies the electricians so approvals are fast and easy. He inspected my work and could find no fault expect for a change to code that happened during my build phase. The change was unnecessary because we were using micro-inverters. It took another more knowledgeable inspector and a debate to get that settled. The inspector's life is made easy if every installation looks the same and in our case it didn't.

In the end we were approved and connected. After a year of operation with a small array we generate more than enough to power a couple of Teslas. We run our cars on sunshine now.

Regarding the HPWC... just get one. They are very robust and suited to outdoor installation which was important in our case. When our car is stored in the garage I connect via 14-50 but when parked outdoors (mostly) the HPWC does the job very well. In addition, an outdoor HPWC is easily shared with other Tesla owners needing an emergency charge even when we are not at home. There are benefits.

 

[cmd_keen]

Hmm...got my 24' HPWC today. I'm still debating on installing it or the NEMA 14-50 because I'm only going to be running the 40A from the 50A breaker.

View attachment 205746

Don't forget the best benefit... pressing the button on the HPWC handle to open the charge port!!!

 

[Maximapolak]

Don't forget the best benefit... pressing the button on the HPWC handle to open the charge port!!!

Then I'll have to install it.

 

[GlmnAlyAirCar]

Don't forget the best benefit... pressing the button on the HPWC handle to open the charge port!!!

Ummmm, UMC does the same thing.

 

[Yinn]

Ummmm, UMC does the same thing.

This, my OA specifically showed me this on my test drive with the UMC.

I went with a 8' HPWC for a couple of reasons.

1) Insurance; I know my wife isn't going to throw the UMC into the trunk every morning and we wanted the UMC in the trunk as a just in case. UMC = $500. HPWC = $500. Wiring needed to be run either way so it was even.
2) Future proofing in case we purchased a 2nd Tesla, a 2nd HPWC would give us an energy management system for charging vs the UMC.
3) Safety, I have a little one and a HPWC being wired in vs a plug was just a little extra peace of mind. They don't make outlet covers for the NEMA huh??
4) It's a more organized installation for the garage which makes the cable more manageable or as my wife says "prettier"

And lastly I'm just justifying my purchase - the charging rates were slightly higher with the HPWC even without the upgraded charging.