Wall charger installation question

[digitaldad]

@tkt546, if you do/already have hooked this up, you'd be safe to do so if you lower the max amperage settings on the wall connector...or at least the car/app (lower to 40 amp charging).

I would then ask the eletrician back to swap the 60 for a 50 amp breaker and you should then be smooth sailing (if you dont feel comfortable connecting the wires to the charger, just have he/she do it when they return for the breaker swap is my vote).

Good luck!

 

[howardnj]

It's true that many electricians do that, but it is obviously, blatantly a code violation. The wire must meet the circuit rating. And running a continuous current of 48A would mean that the full rating of the circuit must be 125% of that, or a full actual 60A circuit. That 6 gauge Romex is only able to meet a rating of 55A, so it is insufficient for a 60A circuit. It's just wrong.

Even a lot of electricians seem to misunderstand that round up case a lot of the time. We see this constantly in this forum.

That is exactly why I chose a recommended Tesla electrician near my location and who was familiar with the local electrical code in my location.. They told me 75% of their current work is installing EV charging stations.
I read many posts prior to deciding to purchase a Tesla and upgrade my old 200 amp Federal Pacific basement panel.
A house in NJ cannot be sold with a Federal Pacific panel. I never would have thought of running 150 ft of #2 aluminum 4 conductor wire from my 200 amp basement panel to the 100 amp garage sub panel for my gen 3 HPWC. Cheaper and lighter than copper.
When I mentioned to the electrician that I receive a 10% military discount at home depot he told me they do not get their supplies at home depot but gave me a 10% discount anyway. I also did not know that my local code requires a black plywood backboard and home depot does not carry them but the local electrical supply house does. The supply house also does not carry the cheap electrical shyt that home depot carries.
I want to be able to sleep at night when I finally receive my M Y charging at 48 amps without worrying about burning down the house.
When the local inspector showed up he was impressed with the job. He left happy and I'm happy

 

[tkt546]

I’m not arguing whether anyone is right or wrong on the technical specifications, because honestly, I don’t know. That’s why I hired someone to run the wire. Also, I appreciate all of the advice.

However, Tesla’s own installation manual says, “If installing for maximum power, use minimum 6 AWG, 90C rated copper wire…”

I get that’s the minimum, but everyone is saying it’s below the minimum or outside of code. It’s what Tesla recommends.

Like I said, not looking to argue, just don’t understand why so many people say there’s a problem.

 

[weathergeekdan]

I'm just getting started with planning my charger. My vehicle won't be here for another month or two but I want it all setup. It seems to me the best setup is 4 AWG and a 60 amp breaker. The instructions say the lugs are rated for 4 AWG but I haven't seen where it it necessary to run 4/2 wire the charger. 4/2 is hard to find, it's more common to find 4/3 and just not use the one wire. I'm a remodeling contractor and have an electrician that works on all my jobs. He says in PA it's legal to run a 6 gauge wire to a 60amp breaker but in NJ it's not code compliant but it does work and they don't have any issues. Many other states it's legal to use 6/2 to a 60amp.

 

[Glfguy8]

I’m not arguing whether anyone is right or wrong on the technical specifications, because honestly, I don’t know. That’s why I hired someone to run the wire. Also, I appreciate all of the advice.

However, Tesla’s own installation manual says, “If installing for maximum power, use minimum 6 AWG, 90C rated copper wire…”

I get that’s the minimum, but everyone is saying it’s below the minimum or outside of code. It’s what Tesla recommends.

Like I said, not looking to argue, just don’t understand why so many people say there’s a problem.

Totally understandable, it is confusing. If you're using a wire like THHN 6 AWG you're good for up to 55 AMP continuous, the rub is that sheathed, Romex-like cable is only rated to 44 AMP continuous, and it's on the homeowner / electrician to make sure the entire circuit is up to code.

If you're really concerned about it, it's simple to de-rate your wall charger to 40 AMP. You're likely to not even notice the difference in charging speed.

 

[Rocky_H]

However, Tesla’s own installation manual says, “If installing for maximum power, use minimum 6 AWG, 90C rated copper wire…”

I get that’s the minimum, but everyone is saying it’s below the minimum or outside of code.

There is a difference between a warning about a minimum level versus a specific recommendation.

They are saying 6 gauge as a minimum, because there is no case at all where 8 gauge wire would ever be acceptable. So 6 gauge is the smallest that is ever allowed. That's why it's a minimum. But it goes without saying that the circuit should also meet electric code.

It’s what Tesla recommends.

It's not recommending to ONLY use 6 gauge. It says that is the smallest you could use. And if it is a setup with conduit and individual wires in there, then 6 gauge is acceptable. Also, if it's MC cable, that has a higher amp rating than NM-B cable, so 6 gauge would work if that is being used too.

I don't get why so many people are looking for excuses and loopholes to try to get away with violating code on electrical installations.

He says in PA it's legal to run a 6 gauge wire to a 60amp breaker but in NJ it's not code compliant but it does work and they don't have any issues.

I would love to hear what this supposed notion is. That's not something that gets to vary state by state. It's in the National Electric Code. Now some places are just super picky, like Chicago requires wire in conduit for absolutely EVERY circuit, so Romex cable isn't allowed to be used anywhere at all, which is kind of ridiculous and seems to be trying to sell more conduit and make jobs take longer to create more billable hours. But that's not fudging on the amp ratings that the national code requires, so I don't see how either NJ or PA could have a difference on that.

 

[tkt546]

There is a difference between a warning about a minimum level versus a specific recommendation.

They are saying 6 gauge as a minimum, because there is no case at all where 8 gauge wire would ever be acceptable. So 6 gauge is the smallest that is ever allowed. That's why it's a minimum. But it goes without saying that the circuit should also meet electric code.


It's not recommending to ONLY use 6 gauge. It says that is the smallest you could use. And if it is a setup with conduit and individual wires in there, then 6 gauge is acceptable. Also, if it's MC cable, that has a higher amp rating than NM-B cable, so 6 gauge would work if that is being used too.

I don't get why so many people are looking for excuses and loopholes to try to get away with violating code on electrical installations.


I would love to hear what this supposed notion is. That's not something that gets to vary state by state. It's in the National Electric Code. Now some places are just super picky, like Chicago requires wire in conduit for absolutely EVERY circuit, so Romex cable isn't allowed to be used anywhere at all, which is kind of ridiculous and seems to be trying to sell more conduit and make jobs take longer to create more billable hours. But that's not fudging on the amp ratings that the national code requires, so I don't see how either NJ or PA could have a difference on that.

It’s not exactly a minimum, it says minimum for maximum power. Kind of a weird way to say it, but whatever.

Also, I’m not trying to find excuses or loopholes. I hired a professional, and gave him the installation sheet that has the power breakdown including the above mentioned quote. I told him I wanted to have the maximum available (even if I don’t end up using it) and this is what he installed.

Now several people are saying it won’t work, so I’m just questioning that, because what limited knowledge I have on the subject seems it should be fine. What mean by this is… the Tesla install sheet says for maximum charge rate use a 60 amp breaker and at least 6 AWG wire. I’m just confused why that’s wrong?

 

[ucmndd]

However, Tesla’s own installation manual says, “If installing for maximum power, use minimum 6 AWG, 90C rated copper wire…”

True story. The problem is 6/3 NM cable doesn’t meet those standards since it’s only rated to 60C, not 90C.

 

[weathergeekdan]

True story. The problem is 6/3 NM cable doesn’t meet those standards since it’s only rated to 60C, not 90C.

I'm either going to go 4/3 NM or if I go 6 gauge I'll go MC and then I won't need conduit once it goes in the garage. I have about a 55' run from my panel to the garage. Will use a Siemens 60amp breaker.

 

[tkt546]

@Rocky_H
After having time to go through everything on here and some other resources, I understand why there's a problem with my configuration.

It just really annoys me because when I told the electrician I wanted to have the maximum charging rate available, he upgrade the breaker from 50-60, but apparently didn't upgrade the wiring properly. If I would have known this earlier, it would have been a simple fix as I had left that section of the wall open for the install so I could have just swapped out the wire. However, once I had it installed, I finished the sheetrock and it's going to be pain to replace the wire.

After speaking with my wife, we decided that I should just pick up a 50 amp breaker and swap it out with the 60 since that's the cheapest\easiest solution.

 

[Rocky_H]

the Tesla install sheet says for maximum charge rate use a 60 amp breaker and at least 6 AWG wire. I’m just confused why that’s wrong?

The exact reason why is that the words "6 AWG wire" are vague and not descriptive enough to be exact and refer to a specific thing. There are at least 3 or 4 different kinds of wire and cable that can be in 6 AWG size. And they all have different temperature ratings and amp ratings. So just saying "6 AWG wire" does not give enough guidance. And some of those types of wire are rated high enough to be allowed for a 60A circuit and some are not.

After having time to go through everything on here and some other resources, I understand why there's a problem with my configuration.

Cool.

It just really annoys me because when I told the electrician I wanted to have the maximum charging rate available, he upgrade the breaker from 50-60, but apparently didn't upgrade the wiring properly. If I would have known this earlier, it would have been a simple fix as I had left that section of the wall open for the install so I could have just swapped out the wire. However, once I had it installed, I finished the sheetrock and it's going to be pain to replace the wire.

After speaking with my wife, we decided that I should just pick up a 50 amp breaker and swap it out with the 60 since that's the cheapest\easiest solution.

Yeah, kind of stinks that he did not do what you were asking for. But a 50A circuit isn't bad at all, and you will probably never notice a difference. It's just going to annoy you mentally that you don't have what you wanted and asked for.

 

[TBrownTX]

I'd swap for a 50 amp breaker. A 60 amp breaker would require 4/3/NM-B.

Tim

 

[weathergeekdan]

I'd swap for a 50 amp breaker. A 60 amp breaker would require 4/3/NM-B.

Tim

or use 6/2 MC or 6/3 MC and it will work with a 60amp. There's still many licensed electricians that state the code allows 6/2 Romex to be used with a 60amp breaker. I am a contractor so my electrician is going to give me a good deal, we are going with a 100amp subpanel in my garage which is about a 55' run from the panel. Then I can have a 60amp and short 4/3 NM line to the wall charger.

 

[terranx]

That's not something that gets to vary state by state. It's in the National Electric Code.

Technically that's not the case. States can choose to have different / lower requirements than what's in the NEC. Just don't think anyone deviates much from it.

I do think the code should be more clear on this matter though. If the intent is to prevent a fault condition from causing the wire to be run in an unsafe manner, then the requirement should be the next rounded down breaker, not rounded up. Or at the very least there should be some labeling requirements when an upsized breaker is used

 

[dgbehrends]

I am about to have a gen 3 wall charger installed. I want the maximum output of 48amps and am going with a 60amp breaker on my main panel. My wire run is about 60ft. The install manual states 6-3 90C copper wire is acceptable to utilize the 48A output. I read through this thread and the conclusion was that 6-3 wire isn't acceptable. Is that because the OP's installed wire is not 90C rated? I normally would just go with 4-3 copper if there was any doubt but there is a huge price increase for 4-3 and it is hard to get. My electrician said he would have to order it from out of state.

Edit: I'm running the 6-3 and not 6-2 as I may later want to turn it into a 14-50 outlet.

thoughts?

 

[terranx]

6 awg romex (aka nm-b) is only rated for 60°C. THHN is rated for 90°C, as is MC cable.

 

[dgbehrends]

6 awg romex (aka nm-b) is only rated for 60°C. THHN is rated for 90°C, as is MC cable.

Right! that is what I was thinking. I'm guessing 6awg THHN or MC will be cheaper than 4awg romex.

 

[ucmndd]

The install manual states 6-3 90C copper wire is acceptable

No, the manual states 6awg 90c conductors are the minimum requirement for max power output.

6/3 nm-b is not rated to 90c in the US, it’s limited to 60c by code.

 

[dgbehrends]

No, the manual states 6awg 90c conductors are the minimum requirement for max power output.

6/3 nm-b is not rated to 90c in the US, it’s limited to 60c by code.

Yes I understand 6/3 nm-b is not acceptable and I won't be using it. That's what the OP's electrician must have installed. 6awg 90c wire is the minimum req for max power output which is as I stated acceptable.

 

[dgbehrends]

Pricing per foot from www.wireandcableyourway.com
6/2 MC $3.38 75A
6/3 MC $4.50 75A
6/2 THHN building wire $1.06 75A
4/3 nm-b $11.73 70A

I'm tempted to go with the 6/2 and give up on any notion of installing a 14-50 down the road. They didn't have 6/3 THHN.