Dialed in ev chargers

[wwhitney]

#4 romex out of the wall into the back of a 4-11/16 sq box. Then 3/4 " EMT from the box to the charger. I can use the 75*C or even 90*C rating for the #6 ? So then a 60A breaker is not over amping the #6? Does this make sense?

Yes, that is what I originally suggested in this post, although without spelling out that the NM would be #4 and the 75C method would be #6 Cu.

Chargepoint EV Charger Question

Residential customer purchased a Chargepoint EV charger for his garage and near future EV. He originally asked for 40AMP charging which would require #6 awg copper, a 40AMP breaker and a NEMA 14-50 receptacle to mate to the Chargepoint plug. He then changes his mind and wants it direct wired to...

xenforo.mikeholt.com

Cheers, Wayne

 

[Amps]

Yes, that is what I originally suggested in this post, although without spelling out that the NM would be #4 and the 75C method would be #6 Cu.

Chargepoint EV Charger Question

Residential customer purchased a Chargepoint EV charger for his garage and near future EV. He originally asked for 40AMP charging which would require #6 awg copper, a 40AMP breaker and a NEMA 14-50 receptacle to mate to the Chargepoint plug. He then changes his mind and wants it direct wired to...

xenforo.mikeholt.com

Cheers, Wayne

I thought so, just helps me to have it clarified. Thank you very much. This job is going to be a PITA getting the cable fished through 100ft of finished ceiling with access panels every so often. I didn't need the inspector failing it for something I over looked, hence all my detailed questions. Thank you again!

 

[wwhitney]

I can use the 75*C or even 90*C rating for the #6 ?

BTW, you've stated previously that the EVSE terminations are rated at 105C. If true, you could in fact use the 90C rating for the #6, I believe.

However, far more common is that a lug may be stamped with the 105C marking just to indicate that the lug itself is limited to 105C. But once that lug is integrated into a piece of equipment, the overall equipment termination limit becomes 75C, because other nearby components are not rated for 105C.

Cheers, Wayne

 

[Amps]

BTW, you've stated previously that the EVSE terminations are rated at 105C. If true, you could in fact use the 90C rating for the #6, I believe.

However, far more common is that a lug may be stamped with the 105C marking just to indicate that the lug itself is limited to 105C. But once that lug is integrated into a piece of equipment, the overall equipment termination limit becomes 75C, because other nearby components are not rated for 105C.

Cheers, Wayne

Very good point. Thank you for that. 75C will be fine for the application. With #4 romex, they do not make 4/2 so 4/3 must be used $$$$. That's why I'm considering #6/2 MC cable, at 75C with a 60A breaker to get the same result as using #4. We use the 2017 NEC. I'm at 110.14(C)(a)(3).

 

[jaggedben]

To the original question...
Take the example of a 125A subpanel fed with 6awg on a 60A breaker. What's to stop some yahoo from coming along and replacing the breaker with a 70, or 80, or a 125?

Generally what stops people from doing stupd dangerous illegal things with electrical installations is either:

1) They don't know enough to change it themselves anyway, and it's too much bother for them.
2) They know they are not qualified and are smart enough to consult someone who is, or
3) they are qualified and know what is to code and what's safe

I think UL standards generally aim to keep most people in category 1. I'm sure the standard for EV chargers requires that this sort of thing is not a 'user setting', and there is generally at least one layer each of physical material, knowledge and warning label to get past to change the setting. Maybe overtime this will prove to be not enough and UL will adapt, but I'm a bit doubtful that will be necessary. There's also the likely scenario in this case that if someone is smart enough to change the setting but not to change the breaker, the breaker will trip and thus alert them they made a mistake. For that small segment of people who know enough to be dangerous but aren't smart or responsible enough to stop themselves from doing it, there are plenty of other examples of stupid things that they could do if they are so motivated, but that may be more of a law enforcement and insurance issue than a code and UL standards one.

 

[curt swartz]

4/3 AL SER or SEU to 664 or larger can. Polaris IT-4's or = with #6 cu to charger.

I have never understood why so may people use #4 and #2 cu NM-B cable with the the 60C ampacity limitation.

 

[kwired]

BTW, you've stated previously that the EVSE terminations are rated at 105C. If true, you could in fact use the 90C rating for the #6, I believe.

However, far more common is that a lug may be stamped with the 105C marking just to indicate that the lug itself is limited to 105C. But once that lug is integrated into a piece of equipment, the overall equipment termination limit becomes 75C, because other nearby components are not rated for 105C.

Cheers, Wayne

Wouldn't you still be limited by what is likely a 75C termination on the other end?

 

[wwhitney]

Wouldn't you still be limited by what is likely a 75C termination on the other end?

The context of the discussion involved splicing conductors in a junction box, so on the EVSE side of the splice, the other end would be a connector that could be rated higher than 75C.

Cheers, Wayne

 

[kwired]

The context of the discussion involved splicing conductors in a junction box, so on the EVSE side of the splice, the other end would be a connector that could be rated higher than 75C.

Cheers, Wayne

 

[Amps]

The electrical supply house I use quoted me prices for 125 ft- 6/2 romex and 125ft -6/2 MC cable. MC cable is $4.00 less. If the 75C column of 310.15 (B)(C) can be used for the MC, then the 4//3 romex, junction box, EMT, #6 THHN taps, Polaris IT-4s plus labor is not needed. The MC #6 can direct wire to the charger. (125ft of 4/3 romex is $791.00 more than the MC cable.) Customer wants copper so AL SER / SEU is out.

 

[Amps]

4/3 AL SER or SEU to 664 or larger can. Polaris IT-4's or = with #6 cu to charger.

I have never understood why so may people use #4 and #2 cu NM-B cable with the the 60C ampacity limitation.

Here is what is in Chargepoint's installation guide: "10. Use 90°C wire copper conductors only."

 

[curt swartz]

Here is what is in Chargepoint's installation guide: "10. Use 90°C wire copper conductors only."

That just applies to the final termination. You can use AL then convert to CU.

 

[Amps]

That just applies to the final termination. You can use AL then convert to CU.

That's what I figured. Wondering how the inspector will interpret it.

 

[Hv&Lv]

I just find it odd that a device rated at a maximum rating can be altered to a lower rating and that rating can be what is used for over currant protection . I get a Homeowner can do what they want like change a breaker which has risk . I just witness a video of an electrician putting in electrical for ford's EV charger . The owner thought he got a 80 amp setup but it looked more like a 40 amp setup . He dialed it up to 80 amps but good for him the unit went into fault mode and stopped charging . He had the electrician come back and install a 100 amp circuit . It just seems to me the code blew this one with the electrical fires we have seen from charging EVs . It was disturbing to see this guy pull off the plastic cover and turning the dial to different amperages with a small screw driver not having a clue what he was doing . I think it's a problem .

How is it any different than this??

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