davewill
Active Member
You have to reconfigure the Wall Connector itself by connecting your phone directly to the Wall Connector after cycling the power. The procedure is in the manual.
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Electrician installed wall connector using Romex 8/3 + 60A breaker
- Thread starter explosive0
- Start date
I have tried everything and I can't connect. I flipped breaker and when I scan the QR Code it just won't take me anywhere. Going to sleep on it and see what I can do tomorrow...Thank you to everyone for your help.
As soon as I typed this I got in! Changed the breaker to a 50 amp so it maxed out 40 amp output. Thanks again.
So, to summarize:
- Ya got 55A wire in there. (That's the ROMEX).
- You're putting in a 50A breaker. That's good. If there's a short at some point somewhere, the breaker pops before the wire catches on fire, a good thing. (Whereas a 60A breaker with 55A wire might, as a corner case, sustain 57A which will light the wire on fire. Half-kidding, but, still.)
- You're reconfigured the TWC so it reports to the car that it's on a 50A circuit. Then, the car, which is the thing actually drawing the current, never draws more than 40A.
If, at some point in the relatively near future, if you're feeling somewhat bloody minded about that electrician, you get them to fix their blame work, replace the wire type with the correct type for the installation that can handle 60A or more, swap out the 50A breaker for a 60A breaker, re-jigger the TWC, and then you'll get 48A of charge current and 48 miles of charge per hour. Probably won't make any difference to your life.
This is a very helpful summary, thank you. I don’t think I will have him pull new wire. Just replace with 50 amp. Model Y charges fast enough as is and even though he messed up, I like him and want to be fair. Feel a ton better and can finally get some sleep. Thank you!!!
SageBrush
REJECT Fascism
FYI, this is not about a short, the underlying issue is to not overheat the wire with a continuous load over 55/1.25 = 44 Amps. Since the TWC lets you choose 40A or 48A load, you choose 40A.
SageBrush
REJECT Fascism
You are making a subtle point. The NEC instructs to choose wire ampacity based on (continuous) load, and then to choose a breaker based on wire ampacity with the provision that the next higher breaker size can be used if the ampacity falls between standard breaker sizes.
This is an example of the NEC being *minimal* requirements. Good practice says not to install this way because a future house owner may look at the breaker and conclude that a higher load is safe. Or the TWC may lose its software setting and default to 48A
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The reason this problem happens is the code is not clear enough IMO. Electrcians will tell you because there is no 55 amp breaker they can round up. They will also say that the EV charger is hard wired and will not pull more than 48 amps (less than the rated ampacity). Lastly they will say the insulator is rated for 90C but is derated by code to 60C.
To complicate matters further try and go get some 4/2 or 4/3 ROMEX. If your able to locate it its at a much much higher cost than #6.
Need to be more clarity from the NEC as EV charger installs are growing!
To complicate matters further try and go get some 4/2 or 4/3 ROMEX. If your able to locate it its at a much much higher cost than #6.
Need to be more clarity from the NEC as EV charger installs are growing!
It’s more complicated than that even, as some states amend the NEC to change the rules, for example here in MA.
The 2020 NEC (NFPA 70) 334.80 paragraph 1 reads:
334.80 Ampacity. The ampacity of Types NM and NMC cable shall be determined in accordance with 310.14. The ampacity shall not exceed that of a 60°C (140°F) rated conductor. The 90°C (194°F) rating shall be permitted to be used for ampacity adjustment and correction calculations, provided the final calculated ampacity does not exceed that of a 60°C (140°F) rated conductor. The ampacity of Types NM and NMC cable installed in cable trays shall be determined in accordance with 392.80 (A).
Which is very clear: you use the 60C column, and so copper #6 is good for 55*.8=44A continuous.
But here in MA ( https://www.mass.gov/doc/state-electrical-code-massachusetts-amendments-2020/download ) they modify this section:
334.80. Delete the second paragraph and revise the first paragraph to read as follows:
334.80 Ampacity. Type NM, and NMC cables shall have conductors rated at 90°C (194°F). Where installed in thermal insulation, the ampacity of conductors shall be that of 60°C (140°F) conductors. The ampacity of Types NM, and NMC cables installed in cable tray shall be determined in accordance with 392.11.
With this updated wording, NM (romex) is only limited to the 60C column if it is installed in insulation. Otherwise, you can treat it the same as THHN/90C rated wire (which makes sense, because… it is the same!). That means for most cases, using the 75C column, giving you 60A*.8=48A continuous.
Also, in either case, a 60A breaker is the correct size breaker for #6 NM/romex
TLDR: If your #6 romex is not installed in insulation, it is perfectly safe to run at 48A continuous. Whether or not that meets your local code depends on the specific local language that was adopted.
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sleepydoc
Well-Known Member
Awesome find. Ive been saying for quite a while (most recently in this thread) that the NEC is very conservative and the de rating for NM-B was done because of the corner case of running it in a hot attic nestled in insulation. Since the vast majority of installs don’t do that, most people can feel safe (but admittedly not NEC code compliant) with an electrician’s install of 6 gauge NM-B on a 60A breaker.
Nice to see that MA officially recognizes this making such installs code compliant in MA.
jebinc
Well-Known Member
You
You anre are not wrong; for Romeo cable, it’s 4AWG. And don’t pay the idiot more as this was thier mistake.
The responses never addressed every point that @heavync stated:
"My electrician installed 60 amp with 6/3 Romex.
"20 ft run; Last 4 ft in conduit."
"Am I ok?"
Does the last 4 ft in conduit affect the rating of the 6/3?
Also, @heavync never confirmed that the Romex was installed indoors (only dry locations; not wet, not outdoors.)
The 60A breaker should be changed to 50A so that in the future someone does not see the 60A breaker, assume the wiring is rated for charging at the full 48 amps, start using the circuit for EV charging at higher than the maximum safe charging amperage. (44A maximum or else use 40A as the maximum when charging as in this case when the next higher setting on the EVSE is for charging at 48A (48A is too high for NM-B 6 gauge wire *).
* Except in Canada where they don't use NM-B wire. In Canada they use NMD-90 (Rated for 90C) instead. Romex is a brand name, not a wire type and yes, Romex sells NMD-90 wire in Canada.
"My electrician installed 60 amp with 6/3 Romex.
"20 ft run; Last 4 ft in conduit."
"Am I ok?"
Does the last 4 ft in conduit affect the rating of the 6/3?
Also, @heavync never confirmed that the Romex was installed indoors (only dry locations; not wet, not outdoors.)
The 60A breaker should be changed to 50A so that in the future someone does not see the 60A breaker, assume the wiring is rated for charging at the full 48 amps, start using the circuit for EV charging at higher than the maximum safe charging amperage. (44A maximum or else use 40A as the maximum when charging as in this case when the next higher setting on the EVSE is for charging at 48A (48A is too high for NM-B 6 gauge wire *).
* Except in Canada where they don't use NM-B wire. In Canada they use NMD-90 (Rated for 90C) instead. Romex is a brand name, not a wire type and yes, Romex sells NMD-90 wire in Canada.
There is no problem running romex in conduit, nor does such an installation need a de-rating as a result of running it in conduit (and even if it did, you would derate from the 90C column, so it wouldn’t matter here).
A 60A breaker is the correct (and code compliant) size breaker for almost all #6 NM-B installations. The code *specifically* requires you to install a breaker 125% of the continuous load (or the next “standard” size up, of which 55A is not one of them) on your circuit to reduce any occurrence of nuisance tripping.
Both a 44A and a 48A continuous load get a 60A breaker. A 40A continuous load could get a 50A breaker, but a 60A breaker is also appropriate if everything in the circuit is sized appropriately (as it is with #6 copper)
SageBrush
REJECT Fascism
I don't read it that way *at all*; and in fact, states do not have the right to set provisions more lax than than the NEC
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How do you read it? And of course they do. The NEC itself is merely a guideline. In the US, it is up to each state (and in some case each city…) to adopt and enforce the code, and at the end of the day, what your inspector/AHJ says trumps even that.
Said another way: Each state adopts a specific version of the electrical code and signs it into law. The NEC itself is not enforceable on its own without being signed into law first, and every state can decide for itself what parts to use (or none at all!)
To use an example, again from MA because that’s where I live. Right now MA has adopted (signed into law under 527 CMR as the “Massachusetts Electrical Code”) the *2020* NEC. The latest revision of the NEC (NFPA 70) is the *2023* version. But whatever changes are included in the 2023 NEC are not relevant for any project in MA currently, because we have not (yet) signed that version into law.
Made up hypothetical to hopefully drive this home: If the 2020 NEC said all neutral wires need to be white, but the 2023 NEC said they needed to be pink with sparkles, electricians in MA would continue to install white neutral wires since we still use the 2020 code. And when the state legislature votes on adopting the 2023 NEC, if we don’t like the pink sparkle requirement of the 2023 version but do like everything else, we can choose adopt a modified version of the 2023 NEC that removes that change!
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SageBrush
REJECT Fascism
I am happy to make a wager with you for ... say $10,000 that you will NEVER find an instance in recent memory -- say 15 years -- in which state amendments to their adopted NEC version that allows more lax provisions than the adopted NEC version. AHJ field authority on a case by case basis is a different matter.
Why 15 years ? That is well within the timeframe that the NFPA was given NEC jurisdiction, and so far as I know no state currently follows NEC older than 2008
Contact me via PM to set up the wager
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