Chargepoint EV Charger Question

[david luchini]

I just got off the phone with Chargepoint "installer support". The person I spoke with said basically what is in their manual and that #6 copper is used for the terminals. He said that I should tell the customer that they cannot go to 50AMP and just use 40AMP since the gain is only a few miles or charge more.

Run the #4 romex thru the building and then transition to #6 thhn in conduit in the garage.

If I could install the entire circuit in conduit, then I could use #6 THHN and the 90 degree column in Table 310.15(B)(16) and get 75A.

You can't use the 90 degree ampacity.

 

[Amps]

For anyone who is still interested, here are two pages from the Chargepoint HomeFlex installer manual that have the electrical.

 

[Amps]

My GUESS is that their cordset to the EV is limited to that?

And the NEMA 14-50 receptacle.

 

[Amps]

Run the #4 romex thru the building and then transition to #6 thhn in conduit in the garage.

You can't use the 90 degree ampacity.

Why not?

 

[wwhitney]

And the NEMA 14-50 receptacle.

With a NEMA 14-50 receptacle in the circuit, the breaker is limited to 50A, and so the EVSE is limited to 40A. If you want to go above 40A, you need to hardwire.

As to the 90C ampacity, you can use it as a starting point for ampacity adjustment or correction, but the terminals at the equipment and the breaker will be limited to 75C. So the circuit ampacity is also limited to the unadjusted 75C ampacity, whichever is less.

Cheers, Wayne

 

[Amps]

With a NEMA 14-50 receptacle in the circuit, the breaker is limited to 50A, and so the EVSE is limited to 40A. If you want to go above 40A, you need to hardwire.

As to the 90C ampacity, you can use it as a starting point for ampacity adjustment or correction, but the terminals at the equipment and the breaker will be limited to 75C. So the circuit ampacity is also limited to the unadjusted 75C ampacity, whichever is less.

Cheers, Wayne

Thank you Wayne. So do you mean that for other than NM-B cable, which forces using the 60C column, use the 75C column of table 310-15(B)(C)? As you can tell I am a bit rusty on this!

 

[augie47]

Why not?

Can't use the 90° ampacity if it's terminated on a 60° or 75° device...like a breaker 110.14(C limitation

 

[Amps]

Can't use the 90° ampacity if it's terminated on a 60° or 75° device...like a breaker 110.14(C limitation

thank you very much. Been away from this for a while. The terminals on the Chargpoint are 105* but the breaker will be 75*.

 

[Amps]

Couple more comments -
THHN in a raceway is the best option.
EVSEs do not use a neutral, so 3 conductor cable isn’t necessary.
When you activate a Chargepoint EVSE, you tell them your branch circuit details and they configure it to 80% of that rating. So if you install a 60A circuit, they will configure it to 48A. If you don’t activate through Chargepoint, the unit will default to the minimum 16A.

I was instinctively going with 6/3 because they spec a NEMA-14-50 that has 4 prongs! Thanks!

 

[retirede]

I was instinctively going with 6/3 because they spec a NEMA-14-50 that has 4 prongs! Thanks!

If you mount a 14-50 without a neutral, I’d mark the outlet “EVSE only”. If somebody plugs their RV in, it won’t be pretty.

 

[wwhitney]

If you mount a 14-50 without a neutral,

I'd suggest that's a code violation (*). Many plug-in EVSEs use a 14-50P because it's more common, but it's inefficient as it requires a 14-50R which requires a neutral. If you get one that uses a 6-50P, then you don't have that problem.

But when hardwired, no neutral required.

Cheers, Wayne

(*) Edit: best I can come up with is 406.8 on non-interchangeability. So if there's a 120/240V 14-50R elsewhere (e.g. for a range), it would be a 406.8 violation to use a 14-50R for 240V only. If the 240V only 14-50R is the only 14-50R on the premises, maybe it's not a code violation, just a terrible idea.

 

[Amps]

I'd suggest that's a code violation (*). Many plug-in EVSEs use a 14-50P because it's more common, but it's inefficient as it requires a 14-50R which requires a neutral. If you get one that uses a 6-50P, then you don't have that problem.

But when hardwired, no neutral required.

Cheers, Wayne

(*) Edit: best I can come up with is 406.8 on non-interchangeability. So if there's a 120/240V 14-50R elsewhere (e.g. for a range), it would be a 406.8 violation to use a 14-50R for 240V only. If the 240V only 14-50R is the only 14-50R on the premises, maybe it's not a code violation, just a terrible idea.

Chargepoint's online installer documents show " Determine the plug type purchased by the homeowner. It is either a NEMA 14-50 or 6-50 type plug." The 6-50 makes sense since a neutral is not required. However, the 14-50 mates with the 4 prong plug on the charger so the 6-50 will not work anyway. Best thing to do it direct wire it.

 

[Fred B]

Chargepoint's online installer documents show " Determine the plug type purchased by the homeowner. It is either a NEMA 14-50 or 6-50 type plug." The 6-50 makes sense since a neutral is not required. However, the 14-50 mates with the 4 prong plug on the charger so the 6-50 will not work anyway. Best thing to do it direct wire it.

Internally, Chargepoint ony has 3 wire connections and ignores the neutral connection of the 14-50. Their plug would have a 4 prong on it but neutral not wired in. Not sure if that's compliant or not but sold that way from mfg. Or it can be hardwired or ordered with a 6-50.

 

[retirede]

Internally, Chargepoint ony has 3 wire connections and ignores the neutral connection of the 14-50. Their plug would have a 4 prong on it but neutral not wired in. Not sure if that's compliant or not but sold that way from mfg. Or it can be hardwired or ordered with a 6-50.

It can be ordered with either plug. The instructions allow hardwiring. Hardwiring would be required if the branch circuit rating is greater than 50A.

 

[Amps]

It can be ordered with either plug. The instructions allow hardwiring. Hardwiring would be required if the branch circuit rating is greater than 50A.

On Chargepoint's site, it shows the NEMA 14-50 https://www.chargepoint.com/drivers/home/chargepoint-home-flex
and on Amazon it shows the Chargepoint with a NEMA 6-50 https://www.amazon.com/ChargePoint-Home-Electric-Vehicle-Charger/dp/B07WNXTHNW?th=1

 

[retirede]

 

[BarryO]

I can't run conduit. The cable is being fished through a finished basement ceiling.

Could you fish some ENT and then run THHN through it? Like NM, it is permitted to be fished in finished buildings without support.

I don't understand why the NEMA 14 receptacles are so popular for EV charging, since AFAIK none of them uses the neutral. It's gotten so ridiculous that some models of 14-50's that have gotten a reputation on the EV social media have shot up to crazy prices.

 

[retirede]

Could you fish some ENT and then run THHN through it? Like NM, it is permitted to be fished in finished buildings without support.

I don't understand why the NEMA 14 receptacles are so popular for EV charging, since AFAIK none of them uses the neutral. It's gotten so ridiculous that some models of 14-50's that have gotten a reputation on the EV social media have shot up to crazy prices.

The consensus in the EV community is that the 14-50 was adopted to allow folks to charge at campgrounds where they are commonly found.

After seeing the $10 Levitons and LeGrands melt, everyone wants the Hubble industrial version, which I think Zoro is getting over $100 for now.

 

[Amps]

Could you fish some ENT and then run THHN through it? Like NM, it is permitted to be fished in finished buildings without support.

I don't understand why the NEMA 14 receptacles are so popular for EV charging, since AFAIK none of them uses the neutral. It's gotten so ridiculous that some models of 14-50's that have gotten a reputation on the EV social media have shot up to crazy prices.

That is a great idea but it's 100+ feet with some tight bends. Good to keep in mind for future installations that are shorter. Thank you!

 

[Amps]

Update idea:
MC cable with #6 copper conductors ? Providing the conductor insulation is rated for 75*C or 90*C in 310-15(B)(16) I can use a 60A breaker with 75*C terminals and the charger terminals are at105*C. I checked MC cable article 330 and did not see anything that restricted MC to a table column like NM cable. Am I missing something?