Chargepoint EV Charger Question

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Amps

Electrical Contractor
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New Jersey
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Electrical, Security, Networks and Everything Else.
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 get 50AMPS. So the wire size increases to #4 awg.
Upon checking the Chargepoint manual for direct wire, it shows that the field terminals for direct wire accept #6 awg. I emailed this to Chargepoint and they have yet to get back to me. Anyone run into this and if so what was your work around? Thanks in advance for any input.
 
retirede said:
#6 copper should be sufficient for 50A (65A @ 75C).
Presuming you will run a 60A branch circuit to charge at 50?
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It's a continuous load. 125% of 50A charge load is 62.5A. Using NM-B Romex so I must use the 60 deg column of 310-16 in the 2017 NEC, #6 copper is 55A, 7.5 low, so I have to go to #4 with a 50A breaker. I can't run conduit. The cable is being fished through a finished basement ceiling.
 
Amps said:
It's a continuous load. 125% of 50A charge load is 62.5A. Using NM-B Romex so I must use the 60 deg column of 310-16 in the 2017 NEC, #6 copper is 55A, 7.5 low, so I have to go to #4 with a 50A breaker. I can't run conduit. The cable is being fished through a finished basement ceiling.
Click to expand...

Is it really a 50A EVSE? Most are sized at 48A to use a 60A circuit. NM would be a problem.
 
wwhitney said:
You can set a disconnect or junction box next to the charger, and switch over from NM to a 75C rated wiring method. Or even use 4-4-4 Aluminum SEU cable instead of NM cable.

Cheers, Wayne
Click to expand...
Thank you. 6/3 NM-B to a junction box, and splice to 6THHN into the Chargepoint. The 4-4-4 SER direct to the Chargepoint won't fit under the terminals, but to a disconnect and then to 6 THHN copper to the Chargepoint. Good idea!
 
Amps said:
Thank you. 6/3 NM-B to a junction box, and splice to 6THHN into the Chargepoint. The 4-4-4 SER direct to the Chargepoint won't fit under the terminals, but to a disconnect and then to 6 THHN copper to the Chargepoint. Good idea!
Click to expand...
Wait a second. My mistake. I can't use the 6/3 NM-B at all for a 50AMP circuit continous load. Per Article 334.40 points to Table 310.15(B)(16) 60 degree column, that shows #6 at 55AMP.
I need 62.5A for a 50A load. 4-4-4 SER or #4 copper looks like the only options.
 
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.
 
Be careful about using the SER, Chargepoint I recently installed required copper only conductors, and most SER is Al, and our suppliers around me say they don't have and don't get any in copper.

Also when on the higher amperage setup it will cycle on/off. So not sure if it qualifies as a true continuous load. But it will draw near max that you setup for during the on cycle.
 
Fred B said:
Be careful about using the SER, Chargepoint I recently installed required copper only conductors, and most SER is Al, and our suppliers around me say they don't have and don't get any in copper.

Also when on the higher amperage setup it will cycle on/off. So not sure if it qualifies as a true continuous load. But it will draw near max that you setup for during the on cycle.
Click to expand...

Most all EVSEs require copper conductors, good point.

In my experience, an EVSE will only cycle (or reduce output) when an over temp condition is detected. I need to look closer at Chargepoint to see if they are doing something different. I think it has to be considered a continuous load regardless.
 
retirede said:
If he uses a 50A breaker, Chargepoint will configure the unit for 40A max output. The #4 wire will be a waste.
Click to expand...
Does Chargepoint even make a 50A continuous output EVSE? I think there's some confusion between the output rating and the circuit rating of the EVSE. I.e. maybe the 125% is getting applied twice.

Cheers, Wayne
 
Fred B said:
Be careful about using the SER, Chargepoint I recently installed required copper only conductors, and most SER is Al, and our suppliers around me say they don't have and don't get any in copper.
Click to expand...
Yes, I only suggested the Al SER because there was going to be a junction box to #6 Cu 75C conductors anyway.

Cheers, Wayne
 
wwhitney said:
Does Chargepoint even make a 50A continuous output EVSE? I think there's some confusion between the output rating and the circuit rating of the EVSE. I.e. maybe the 125% is getting applied twice.

Cheers, Wayne
Click to expand...

Their residential model “Homeflex” can be configured from 16 to 50 amps output to the vehicle.
ce8afce36725bd8a21a233f82881d9d8.jpg

I wonder why they bother with 50A. The other configurations all correspond to 80% of a standard breaker size?
 
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.
Of course, this whole mess is caused by using Romex. 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. Unfortunately I cannot use conduit as the basement is finished and divided into many rooms. The only part that is not finished is the room with the electrical panel on the opposite side of where the garage is located. Starting to think about using MC cable.
 
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