Electric Vehicle charger requirements

[godsquadgeek]

my neighbor bought an electric vehicle and asked if He could put a 40amp load on his garage panel. it's 240. I asked him to list everything plugged into that panel. But I am not sure what size 240 breaker you would use for a 40 amp charger 240v. I am thinking number 8 wire right? it's rated for 55 amps at 100 percent. are there any codes about electric chargers? That I am missing, or should this be it?

 

[petersonra]

It is just a regular dedicated load. There are no special rules about it. It is a continuous load. I don't see how you can put a 55 amp load on a number 8 wire though, or put it on a 40 Amp cb.

 

[godsquadgeek]

It is just a regular dedicated load. There are no special rules about it. It is a continuous load. I don't see how you can put a 55 amp load on a number 8 wire though, or put it on a 40 Amp cb.

oh sorry it's a 40 amp load, not 55. I thought a 55 amp #8 would suffice? Thanks for the reply.

 

[godsquadgeek]

I checked a breaker calculator and it said 48 amp breaker for a 240 volt 40 amp charger.

 

[petersonra]

I checked a breaker calculator and it said 48 amp breaker for a 240 volt 40 amp charger.

What is a breaker calculator?

It is a continuous load so your conductor ampacity will need to be 125 % of the maximum load. For single conductors, #8 would work, but not for Romex.

In either case, a 50 Amp breaker is probably in order.

Most people do not have a very big feed to their garage. That would need to be checked and a new load calculation done for both the house and the feeder to the garage.

It seems likely to be a bit sketchy.

I don't know what makes you think a #8 is suitable for 55 Amps.

By the way, please fill in your occupation in your profile.

 

[kwired]

What is a breaker calculator?

It is a continuous load so your conductor ampacity will need to be 125 % of the maximum load. For single conductors, #8 would work, but not for Romex.

In either case, a 50 Amp breaker is probably in order.

Most people do not have a very big feed to their garage. That would need to be checked and a new load calculation done for both the house and the feeder to the garage.

It seems likely to be a bit sketchy.

I don't know what makes you think a #8 is suitable for 55 Amps.

By the way, please fill in your occupation in your profile.

55 is the 90C ampacity, but he still limited to 60 or 75 C for termination rating depending on exactly what kind of wire/cable he is using.

55 can be used as starting ampacity if adjustments are necessary.

 

[godsquadgeek]

What is a breaker calculator?

It is a continuous load so your conductor ampacity will need to be 125 % of the maximum load. For single conductors, #8 would work, but not for Romex.

In either case, a 50 Amp breaker is probably in order.

Most people do not have a very big feed to their garage. That would need to be checked and a new load calculation done for both the house and the feeder to the garage.

It seems likely to be a bit sketchy.

I don't know what makes you think a #8 is suitable for 55 Amps.

By the way, please fill in your occupation in your profile.

filled in occupation, I work at a cannery as an industrial electrician, I am unfamiliar with all residential however. Thanks for the feedback.

 

[kwired]

filled in occupation, I work at a cannery as an industrial electrician, I am unfamiliar with all residential however. Thanks for the feedback.

When it comes to conductor ampacity and overcurrent protection not really any differences than what you are used to other than NM cable must be treated as though it were 60C conductor, but can still use 90C as the starting point for ampacity adjustments as long as it is the newer (30+ years now) NM-B type cable.

 

[godsquadgeek]

When it comes to conductor ampacity and overcurrent protection not really any differences than what you are used to other than NM cable must be treated as though it were 60C conductor, but can still use 90C as the starting point for ampacity adjustments as long as it is the newer (30+ years now) NM-B type cable.

thanks