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

[iluvmacs]

So I decided to create a page summarizing this ampacity stuff and a few other things for EVSE installs on my charging.us web site. Check it out if you have time and let me know if I got anything wrong or missed something. Thanks!

Advice for EV Charging in North America

Advice for EV Charging in North America

carcharging.us

I don't see anything particularly wrong, but many things missing, here are a few:
- GFCI required in most jurisdictions for receptacles (NEC 2017+).
- No mention or discussion of using EMT tradecraft, a very common wiring technique -- more common than PVC, at least in my locale. (Also perhaps mention rigid conduit and FMC?)
- Definitely worth adding a 30A circuit row to your table, as this is quite common. Maybe even 20 and 15 for good measure.
- Probably worth mentioning in the tradecraft that you must use listed couplers and accessories (like straps) for the type you're using (i.e. no using EMT straps for MC unless double-listed). I've seen this mistake very frequently.
- Should have a chart for ground wire gauge sizing (e.g. #10 THHN is good for up to a 60A circuit -- no need to pull a #6 for that), and also when conduit can be used for ground.

 

[Cosmacelf]

I don't see anything particularly wrong, but many things missing, here are a few:
- GFCI required in most jurisdictions for receptacles (NEC 2017+).
- No mention or discussion of using EMT tradecraft, a very common wiring technique -- more common than PVC, at least in my locale. (Also perhaps mention rigid conduit and FMC?)
- Definitely worth adding a 30A circuit row to your table, as this is quite common. Maybe even 20 and 15 for good measure.
- Probably worth mentioning in the tradecraft that you must use listed couplers and accessories (like straps) for the type you're using (i.e. no using EMT straps for MC unless double-listed). I've seen this mistake very frequently.
- Should have a chart for ground wire gauge sizing (e.g. #10 THHN is good for up to a 60A circuit -- no need to pull a #6 for that), and also when conduit can be used for ground.

Good feedback. Yeah, I didn't mention EMT since it is more expensive than PVC, and frankly harder for an amateur to build correctly. More durable for sure, but for household use, it is usually overkill.

I'll put in all your other suggestions though, all solid points, thanks.

 

[iluvmacs]

Good feedback. Yeah, I didn't mention EMT since it is more expensive than PVC, and frankly harder for an amateur to build correctly. More durable for sure, but for household use, it is usually overkill.

I'll put in all your other suggestions though, all solid points, thanks.

My first EMT install, I just bought elbows and couplers. It's super easy if you just need 90's. I think bending PVC is more difficult than using an EMT bender, but just my opinion.

 

[Cosmacelf]

My first EMT install, I just bought elbows and couplers. It's super easy if you just need 90's. I think bending PVC is more difficult than using an EMT bender, but just my opinion.

Still more expensive though!

 

[Justjim]

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?

No, you are correct. Double pull 60A breaker and 6awg wire. However you only need 6/2 wire which is black - L1, red - L2 and ground and cheaper. 6/3 would have a white for common which is not needed.
Someone pointed out that 80% load, which is code, brings the current to 48A.

 

[brkaus]

Can I toss a wrench into the discussion

I have 50A circuit on a Gen2 WC... charging at 40a.

The circuit comes from a breaker in the main panel through rigid into a utility meter. The meter provides me a special off peak ev rate. Then straight back through the wall (meter outside, WC inside) where it goes into a 60a HVAC type disconnect and then down to the WC.

I'm told that the new code requires a sub-panel if I want a second WC sharing the 50a and that sub-panel should basically replace the current HVAC disconnect.

Now, the question... Is it OK to have a sub-panel that is 240v only? Or do they need to pull the meter and pull a neutral through the circuit?


re: the rate... basically they subtract off the EV usage from the main meter and then I get billed separate for EV. With special rules such as if I use 10% or more EV charging in peak time it all reverts to peak.

 

[Cosmacelf]

Can I toss a wrench into the discussion

I have 50A circuit on a Gen2 WC... charging at 40a.

The circuit comes from a breaker in the main panel through rigid into a utility meter. The meter provides me a special off peak ev rate. Then straight back through the wall (meter outside, WC inside) where it goes into a 60a HVAC type disconnect and then down to the WC.

I'm told that the new code requires a sub-panel if I want a second WC sharing the 50a and that sub-panel should basically replace the current HVAC disconnect.

Now, the question... Is it OK to have a sub-panel that is 240v only? Or do they need to pull the meter and pull a neutral through the circuit?


re: the rate... basically they subtract off the EV usage from the main meter and then I get billed separate for EV. With special rules such as if I use 10% or more EV charging in peak time it all reverts to peak.

This really deserves it own thread. And this probably can only be answered properly by someone who knows your specific region’s electrical code and/or your power company’s rules as you are basically asking what does the code say and what your utility allows.

 

[anapon]

Q death star didnt make it clear to non electricians that he was talking about Romex. 6awg is fine if the wire was THHN in conduit, but not fine if NM-B (Romex) was used. So depends what kind of cable/conduit was used in your install.

its the romex cable. i was told it can handle 55 continuous load.. since i am using only 48, it should be good. it was done by a certified technician.

 

[anapon]

If it was inspected and approved, I would go with it. That's the legal standard for "up to code" and will satisfy insurers, future home buyers, etc...

Is the Chargepoint capable of 48a charging or does it top out at 40a? If the latter, I would consider downsizing the breaker to 50a.

48amp.

 

[Cosmacelf]

its the romex cable. i was told it can handle 55 continuous load.. since i am using only 48, it should be good. it was done by a certified technician.

Unfortunately that isn't correct. 6 gauge Romex can handle 55 amps regular load, or 44 amps continuous load. HOWEVER, those ratings are conservative and are meant to deal with situations where the romex is being routed through uninsulated attics that can get really hot in the summer. It is the outer sheathing of the romex cable that can't take the heat (literally) and might melt under extreme conditions. If your installation is under more moderate conditions and especially if the inspector OKed the install, I wouldn't worry about it. If you are really worried, you can flip the dip switches inside the EVSE to charge at a max. of 40A (Unless it had a 44A setting, which would be OK too).

Reference: Cerrowire Resources - Ampacity Charts

 

[qdeathstar]

Q death star didnt make it clear to non electricians that he was talking about Romex. 6awg is fine if the wire was THHN in conduit, but not fine if NM-B (Romex) was used. So depends what kind of cable/conduit was used in your install.

Romex is a brand name. Nm-b is the type of cable, brodensker

 

[qdeathstar]

Unfortunately that isn't correct. 6 gauge Romex can handle 55 amps regular load, or 44 amps continuous load. HOWEVER, those ratings are conservative and are meant to deal with situations where the romex is being routed through uninsulated attics that can get really hot in the summer. It is the outer sheathing of the romex cable that can't take the heat (literally) and might melt under extreme conditions. If your installation is under more moderate conditions and especially if the inspector OKed the install, I wouldn't worry about it.

Reference: Cerrowire Resources - Ampacity Charts

This is wrong. It is not OK. Just because the inspector was unaware of the code doesn’t make the code go away.

Still more expensive though!

A stick of 3/4 emt is 10.38, a stick of pvc is 10.68. Basically equivalent. For long exterior horizontal runs, emt is probably better, otherwise pvc is fine. Emt looks a little better at install but will rust over time outside. Pvc will warp/flex and expand/contract

 

[qdeathstar]

Can I toss a wrench into the discussion

I have 50A circuit on a Gen2 WC... charging at 40a.

The circuit comes from a breaker in the main panel through rigid into a utility meter. The meter provides me a special off peak ev rate. Then straight back through the wall (meter outside, WC inside) where it goes into a 60a HVAC type disconnect and then down to the WC.

I'm told that the new code requires a sub-panel if I want a second WC sharing the 50a and that sub-panel should basically replace the current HVAC disconnect.

Now, the question... Is it OK to have a sub-panel that is 240v only? Or do they need to pull the meter and pull a neutral through the circuit?


re: the rate... basically they subtract off the EV usage from the main meter and then I get billed separate for EV. With special rules such as if I use 10% or more EV charging in peak time it all reverts to peak.

You do not need a neutral. Though I do not think you even need a disconnect for evse less than 60 amps.

625.43

 

[SageBrush]

its the romex cable. i was told it can handle 55 continuous load.. since i am using only 48, it should be good.

A load of 48 Amps for EV charging requires conductors and breaker BOTH rated for 60 Amps.
Your setup is a severe NEC violation and a real fire safety hazard.

Change the TWC to 40 Amp load immediately, and get a competent electrician out to change the breaker to 50 Amps. Or get the correct rated conductors for a 48 Amp EV load.

 

[ucmndd]

Your setup is a severe NEC violation and a real fire safety hazard.

I mean, it’s definitely wrong, but “a severe NEC violation and real fire safety hazard”?

That’s awful dramatic. There are countless installs out there like this, including many many many done by licensed electricians and inspected/approved by AHJs.

Yet somehow we don’t have houses burning down every day from melted NM-B.

 

[Cosmacelf]

I mean, it’s definitely wrong, but “a severe NEC violation and real fire safety hazard”?

That’s awful dramatic. There are countless installs out there like this, including many many many done by licensed electricians and inspected/approved by AHJs.

Yet somehow we don’t have houses burning down every day from melted NM-B.

Yeah, ampacity ratings are set for worst case scenarios, like being strung through an uninsulated attic that reaches 130 degrees in the mid day summer. As long as your NM-B isn't in those conditions, it should work fine.

 

[SageBrush]

I mean, it’s definitely wrong, but “a severe NEC violation and real fire safety hazard”?

Yes

Your clue should be how long ago the NEC stopped this practice

 

[ucmndd]

Yes

Your clue should be how long ago the NEC stopped this practice

Ok. Thanks for looking out for all of us and staying so level-headed.

I’ll be on the lookout for the news stories and forum postings covering all these scorched romex incidents that will undoubtedly result from these severe code violations and fire hazards.

 

[qdeathstar]

Ok. Thanks for looking out for all of us and staying so level-headed.

I’ll be on the lookout for the news stories and forum postings covering all these scorched romex incidents that will undoubtedly result from these severe code violations and fire hazards.

The issue is that that wiring is goin to be around for 50-100 years. Running the wiring/insulation above its intened amperage by even a small amount can/will lead to thermal breakdown of the insulation over time. It isn’t a question of instantaneous melting, but of prolonged additional heat loading.

 

[iluvmacs]

Now, the question... Is it OK to have a sub-panel that is 240v only? Or do they need to pull the meter and pull a neutral through the circuit?

I tried to figure this out some years ago. The answer is... it's up to your AHJ. So call and ask the inspector if it would be approved or not. More than likely, though, they will say no.