Electrician installed wall connector using Romex 8/3 + 60A breaker

[explosive0]

I am by no means an electrician but a licensed electrician just installed my Wall Connector using Romex 8/3 and a 60A breaker for a 40ft run. I believe a 60A breaker should use at least Romex 6/3. I realized this after he had left, and just called him back to come rectify. He tried to convince me that because the wall connector draws only 48A, I should be good.

I insisted he come swap it out for a 6 gauge cable, as specified in the Tesla installation guide. Am I wrong?

 

[exxxviii]

Yeah, that’s wrong. Most folks here will insist that it should be #6 THHN in conduit. Or #4 NM-B (Romex).

 

[240vPlug]

That's definitely wrong! It should be #4 NMB Romex or #6 90C THHN in conduit. 6/3 NMB is borderline because it's only rated for 55amps but because there is no 55 amp breaker your technically allowed to round up. For an EVSE though I would not use the round up method. It's a high power draw that can go on for many hours.

 

[davewill]

Dude's out of his mind. 8/3 Romex is only good for a 40a breaker. He completely screwed the pooch on this one.

 

[explosive0]

Glad to hear that I was right. I've shut off the breaker for now, and will wait for him to come fix.

 

[davewill]

Glad to hear that I was right. I've shut off the breaker for now, and will wait for him to come fix.

Do yourself a favor and have it permitted and inspected. Obviously, the electrician didn't bother with that little detail, either. I wouldn't trust ANYTHING he did or told you at this point.

 

[explosive0]

Do yourself a favor and have it permitted and inspected. Obviously, the electrician didn't bother with that little detail, either. I wouldn't trust ANYTHING he did or told you at this point.

Ugh. Yeah, I'm worried about that now. I'd hate to be out $750. Either I ask him to pull a permit, or count my losses and just go with one of Tesla's recommended electricians and be out $750.

 

[davewill]

Ugh. Yeah, I'm worried about that now. I'd hate to be out $750. Either I ask him to pull a permit, or count my losses and just go with one of Tesla's recommended electricians and be out $750.

You might be able to pull the permit yourself. Depends on your jurisdiction. I think you have to give him a chance to fix it at this point, just make sure someone besides him inspects the work.

Of course if he gives you any more guff, demand a full refund and have it done right by someone else.

 

[explosive0]

You might be able to pull the permit yourself. Depends on your jurisdiction. I think you have to give him a chance to fix it at this point, just make sure someone besides him inspects the work.

Of course if he gives you any more guff, demand a full refund and have it done right by someone else.

Makes sense. I'm a little triggered and jumpy given the fact that he tried to convince me that it was ok, but I'll give him the chance to rectify. My preference would be to go for #4 NM-B, since the boss says she doesn't want any surface conduits in the garage.

 

[240vPlug]

Do yourself a favor and have it permitted and inspected. Obviously, the electrician didn't bother with that little detail, either. I wouldn't trust ANYTHING he did or told you at this point.

This is good advice. A little extra but avoids issues later.

OP: Many folks aren't as knowledgeable as you. It's a good thing you caught this!

 

[davewill]

Makes sense. I'm a little triggered and jumpy given the fact that he tried to convince me that it was ok, but I'll give him the chance to rectify. My preference would be to go for #4 NM-B, since the boss says she doesn't want any surface conduits in the garage.

It's a garage...a few surface conduits just makes it looks lived in. But it's never wise to ignore the Wife Acceptance Factor.

 

[Benito1283]

In my experience inspectors are often useless. I would not count on an inspector to ensure your electrician did a good job. Arguably the most important thing is that the connections and splices are done right, and inspectors aren't going to open receptacles and fittings and test connections. If you're really concerned I'd have another electrician go over the installation.

In terms of your current setup, perhaps you could get some type of refund if you decide to live with the lower charge speed and have him put in a 40A breaker to match the circuit wire. I bet he'd prefer that to doing the entire thing over.

 

[MP3Mike]

That's definitely wrong! It should be #4 NMB Romex or #6 90C THHN in conduit. 6/3 NMB is borderline because it's only rated for 55amps but because there is no 55 amp breaker your technically allowed to round up. For an EVSE though I would not use the round up method. It's a high power draw that can go on for many hours.

There is #6 "Romex" that is acceptable for a 60A breaker, as it is rated for 75C.

#6 x 3 TCERJP Pool, Spa, EV Copper Wire W/Ground | TCERDirect

TC-ER-JP cables are suitable for installation between the service panel and electric vehicle charging stations, pool equipment, or spas when installed in accordance with applicable National Electrical Code guidelines. (UL) E60544 POWER AND CONTROL TRAY CABLE TYPE TC-ER-JP 6 AWG (13,3 mm2) 3/C +...

www.tcerdirect.com

It is also good for direct burial...

They also have a #8 that is good for a 50A breaker.

 

[ucmndd]

6/3 NMB is borderline because it's only rated for 55amps but because there is no 55 amp breaker your technically allowed to round up.

No, you can’t round up unless your calculated load is less than the ampacity rating of the wire. There’s no “borderline” to speak of. 80% of 55 amps is 44 amps. 48 is greater than 44. Thus it’s a no-go.

 

[explosive0]

Just in case y'all are interested in an update - I spent 15 minutes on the phone with the electrician, all while he insisted he was correct; super frustrating. I told him we weren't debating this and he has two choices - swap the cable for a #4 Romex, or #6 MC. He's supposed to call back tomorrow, so we'll see.

Also going to try to convince the wife to just go a surface conduit; that'll make things a lot easier. It's in the garage, so not sure why she even cares.

 

[ucmndd]

Just in case y'all are interested in an update - I spent 15 minutes on the phone with the electrician, all while he insisted he was correct; super frustrating. I told him we weren't debating this and he has two choices - swap the cable for a #4 Romex, or #6 MC. He's supposed to call back tomorrow, so we'll see.

Also going to try to convince the wife to just go a surface conduit; that'll make things a lot easier. It's in the garage, so not sure why she even cares.

You need to be rid of this knob. He’s got no idea what he’s doing.

 

[Pianewman]

If he's "licensed", isn't his standing impacted by improper installations? Can't this be reported to the licensing authority?

He should correct the issue, or refund your money.

 

[SageBrush]

Also going to try to convince the wife to just go a surface conduit; that'll make things a lot easier. It's in the garage, so not sure why she even cares.

I'm not following here. Is the NM-B in a wall ? If it is tacked on to the drywall, you get to take it down and start again. I'd like to see a photo of what you have at the moment.

By the way you have another option here if the NM-B is correctly installed: keep the 8/3, change the breaker to 40 Amps, and run power at 32 Amp continuous. I'll leave it to you to decide how much to pay the "electrician."

--
Addendum: I have no idea about TX. In NM we have licensed electricians and handyman. The latter are not allowed to install conduit. I don't know if they are restricted to a maximum AWG wire, but it seems likely.

Addendum #2, general FYI:
A branch circuit (BC) used for EV charging is continuous use. The wire and breaker ratings must be 125% of the maximum power draw. NM-B wire ratings are per the 60C column in table 310.16 of the NEC. Corrections and adjustments (e.g., due to high temperature) are per the 90C table but that is probably not in play here since the 60C requirement will likely be the deciding factor. Very hot places may end up with a different result.

 

[explosive0]

I'm not following here. Is the NM-B in a wall ? If it is tacked on to the drywall, you get to take it down and start again. I'd like to see a photo of what you have at the moment.

By the way you have another option here if the NM-B is correctly installed: keep the 8/3, change the breaker to 40 Amps, and run power at 32 Amp continuous. I'll leave it to you to decide how much to pay the "electrician."

--
Addendum: I have no idea about AZ. In NM we have licensed electricians and handyman. The latter are not allowed to install conduit. I don't know if they are restricted to a maximum AWG wire, but it seems likely.

It's currently in the wall.

 

[SageBrush]

There is #6 "Romex" that is acceptable for a 60A breaker, as it is rated for 75C.

I'm not so sure. The conductors are THWN, which would allow corrections and adjustments based on the 75C column of Table 310.16
But UF is in the 60C column