EV charger

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olly

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Berthoud, Colorado
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Master Electrician
Are you able to use 8-3 on a 50A EV receptacle. I always see #6 used. not sure why #8 is rated for 50A in 75 degree column
 
Check Art 625 and keep in mind the chargers are considered continuous duty so you are looking at 125% of the maximum load of the equipment. With NM you are likely to need a #6.
 
olly said:
Are you able to use 8-3 on a 50A EV receptacle. I always see #6 used. not sure why #8 is rated for 50A in 75 degree column
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What is amp rating of equiment?

You can put a 40 amp breaker on a 50 amp receptacle, and use 8 AWG @ 60C ampacity - if rating is no more than 32 amps. (continuous load x 1.25)

You can use 8 AWG 75C conductor up to 40 amps (continuous load x 1.25 = 50) on a 50 amp breaker.

If load is more than either of those examples it will need to be at least 6 AWG in each case.
 
kwired said:
What is amp rating of equiment?

You can put a 40 amp breaker on a 50 amp receptacle, and use 8 AWG @ 60C ampacity - if rating is no more than 32 amps. (continuous load x 1.25)

You can use 8 AWG 75C conductor up to 40 amps (continuous load x 1.25 = 50) on a 50 amp breaker.

If load is more than either of those examples it will need to be at least 6 AWG in each case.
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Every EVSE I’ve seen that has a 14-50 plug is rated 40A continuous and calls for a 50 A breaker. That would require 6 AWG NM.

Edit - some can be set internally to limit output to 32A. I think whether or not the circuit can be deprecated accordingly has been debated at length on here previously.
 
There are plenty of EVSEs that support a maximum charging rate of 30A or 32A. Maybe as many as support 40A. Many non-Tesla cars have an onboard charger that is 7.2 kW only.

Cheers, Wayne
 
wwhitney said:
There are plenty of EVSEs that support a maximum charging rate of 30A or 32A. Maybe as many as support 40A. Many non-Tesla cars have an onboard charger that is 7.2 kW only.

Cheers, Wayne
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You are correct - I forgot that those also have a NEMA 14-50 connection.
 
All of the public ones we installed were 40 amp. Had to pull a neutral too, although the EV does not require it. The manufacture used a 120 volt contactor and controls because they wanted it to be universal voltage, 208 or 240. Car doesn’t car, but the contactor did. I think they finally overcome that obstacle.
 
hillbilly1 said:
All of the public ones we installed were 40 amp. Had to pull a neutral too, although the EV does not require it. The manufacture used a 120 volt contactor and controls because they wanted it to be universal voltage, 208 or 240. Car doesn’t car, but the contactor did. I think they finally overcome that obstacle.
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What wrong with a coil rated 208-240 volts? I know not your problem.
 
hillbilly1 said:
All of the public ones we installed were 40 amp. Had to pull a neutral too, although the EV does not require it..
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Car-charger instructions per 110.3(B) are silent regarding inspectors failing NEMA 14-50 for listing violations when missing the neutral.

Some AHJ's complain that occupants can eventually use that 14-50 for appliances requiring the neutral, and red tag if not "Identified" or "Listed" for use without a neutral. Perhaps relying on 110.3(A)(1) Note-2.

I do see garages commonly occupied with extension cords, fire hazard wiring, and 240v clothes dryer's that require the neutral.
 
ramsy said:
Car-charger instructions per 110.3(B) are silent regarding inspectors failing NEMA 14-50 for listing violations when missing the neutral.

Some AHJ's complain that occupants can eventually use that 14-50 for appliances requiring the neutral, and red tag if not "Identified" or "Listed" for use without a neutral. Perhaps relying on 110.3(A)(1) Note-2.

I do see garages commonly occupied with extension cords, fire hazard wiring, and 240v dryer's that require the neutral.
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The commercial ones are all hardwired, so no plug.
 
ramsy said:
Car-charger instructions per 110.3(B) are silent regarding inspectors failing NEMA 14-50 for listing violations when missing the neutral.

Some AHJ's complain that occupants can eventually use that 14-50 for appliances requiring the neutral, and red tag if not "Identified" or "Listed" for use without a neutral. Perhaps relying on 110.3(A)(1) Note-2.

I do see garages commonly occupied with extension cords, fire hazard wiring, and 240v clothes dryer's that require the neutral.
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I generally would never leave neutral of a 14-50 (or a 14-anything) floating. But considering many uses now will require GFCI protection - if for some reason wanted to make sure neutral doesn't get used I'd possibly connect that neutral terminal to the EGC. If anyone connects neutral load to it it will trip the GFCI.
 
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rnatalie said:
The EVSE (that's the thing that's installed in the garage, the charger is in the car) are GFCIs in their own right as well.
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Except for the dc fast chargers, they charge directly while communicating with the vehicle on battery temp and other parameters.
Installed one so new, they had the listing agency come out to the job site to perform the listing inspection. 200 amp 208 volt three phase input. The gas station they put it at was on top of a rocky hill, lightning was constantly taking out the electronics.
 
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