Calling All Electricians - NEMA 14-50 Power

[SomeJoe7777]

Just a mention on permit and inspection: Yes, they cost money, time, and hassle. However, doing it does make sure that your homeowner's insurance company doesn't have an excuse to not cover something should something happen. If there's an electrical fire (regardless of source), and they find that modifications which would require a permit and inspection have been done to the house without said permit and inspection, then they can try to deny a claim.

 

[AB4EJ]

The smaller the cable, the more heating you have. Heating of the cable is power you are paying for but it is being wasted. I like the #6 Cu.

 

[JPoldo]

Thanks for identifying my error. It's not 29 amps/hr for a charge rate but rather 29 miles/hr based on Tesla published data. Thinner copper cable is always easier to pull though conduit elbows. Today, I bought 30 ft (5 ft extra for safety) of AWG 6 THHN stranded cable, 4 conductors. Hope to finish install tomorrow. Now my install is compatible with the HPWC .

 

[tga]

Mongo, thanks for all the tips as most have worked well for me in the past. Sorry, tip #1 is has no value to me.

It is if you want the install to be legal. MA definitely requires a permit for what you want to do.

Interesting MA bureaucracy note - the state allows homeowners to do their own electrical work in owner-occupied single and 2-family homes, provided you get a permit and inspection. But the state also allows towns to refuse to issue permits to homeowners, essentially overriding state law.

 

[JPoldo]

It is if you want the install to be legal. MA definitely requires a permit for what you want to do.
TGA, your support for an electrical permit is clearly justified for amateurs. After 30+ years electrical engineering and numerous bad experiences with permitting, I accept the risk of avoiding them. Last month, I had a tiny low voltage wiring job in Florida and got a permit. Permit cost was $140 for a $300 job and customer refused to pay it. We all take calculate risks every time we drive down the street. I respect your opinion, it's just not for me on work done at my property.

 

[tls]

Yes, I am installing it in conduit and trying to understand why Tesla recommends #6 when #8 should work fine at 25 feet. Maybe they are covering much longer distances such as 100-125 feet. #6 wire cost is 50% more at HD / Lowes plus extra labor to pull 4 lines through conduit. Am I "penny wise & pound foolish" considering #8 cable?

Yes, I think you're being "penny wise and pound foolish". You're going to save, at a maximum, $20 on wire, probably less. Neither run will really fit in 1/2" conduit under the 40% rule -- even with a #10 ground, you're at 43% fill with #8 wire, which you can certainly pull but is not legal -- so you won't save any money on pipe. And why is there "extra labor" to pull #6 in properly sized conduit vs #8? You're only going 25 feet. If it's because you're trying to stuff 4 #6 into a 1/2" EMT (or even 3 #6 plus a #10 ground) -- don't.

If you want to save money and time, and your jurisdiction will allow it (that is, you're not in Chicago) use 6/3 Romex instead. Most jurisdictions will allow Romex to be run through the framing in an unfinished space just as if the walls were up.

 

[Plugsuvohio]

NEC requires a dedicated ground wire but it can be 1 size smaller. Using the conduit is dangerous. I build my house 3+ years ago not having an EV for being certain in a few years we would have one. Had the electrician put in 14-50. The subpanel was only 8' away and they used #6. Keep in mind the load and breaker must be limited to 80% capacity on this kind of circuit. After 9 months, I realized the benefits of HWPC (and they were $50 more then) the longer cable and extra miles per hour are worth it IMHO. We put that in and used #4 because there could be another EV on that branch later.

 

[tga]

TGA, your support for an electrical permit is clearly justified for amateurs. After 30+ years electrical engineering and numerous bad experiences with permitting, I accept the risk of avoiding them. Last month, I had a tiny low voltage wiring job in Florida and got a permit. Permit cost was $140 for a $300 job and customer refused to pay it. We all take calculate risks every time we drive down the street. I respect your opinion, it's just not for me on work done at my property.

Yeah, it was pretty clear where you stood on the issue. I was more pointing out the legal issues for others coming into the thread later. FWIW, I'm pretty confident in my abilities, but I still see value in the inspection and having a second set of eyes reviewing my work.

And requiring a permit for low voltage work is just stupid. You're not going to burn your house down or kill someone installing a phone line improperly.

 

[JPoldo]

Your frank comments are greatly appreciated. The project is 80% done using 4 - #6 THHN wires, black, white, red, and green in 3/4 PVC conduit. I had to use multiple LBs for 90 degree bends. If doing again, I'd upsize to 1 inch PVC. Taping the wires every two feet in perfect parallel pattern helped considerably. Frequent conduit and elbow clamps we're needed because a 10 ft run is fairly heavy. A 50 amp circuit breaker was installed in panel