Nema 14-50 on 20A Breaker?

[crackers8199]

i have a similar (but different) question, kinda related to this though so i'll ask it here.

prior to the model 3, my daily driver was a 2013 chevy volt that is now my wife's car. when we had our house built, i had it built with a 14-50 outlet installed in the garage to charge the volt...but since the onboard charger in the gen 1 volt can only do 3.3kw, i just bought a clipper creek LCS-20 and threw a 14-50 plug on the end of it, plugged it in and called it a day. worked great.

now that we have the model 3, the volt parks on the other side of the garage so i can charge the model 3 from the 14-50 using the UMC that came with the car. what i'd like to do is put the CC LCS-20 back into service on the other side of the garage without spending a fortune. there's no 220 outlet over there, but there is a subpanel that is directly on the other side of the wall from the main electrical panel outside. it runs on a 50 amp breaker from the main panel, and has two open slots. it mainly powers the lights and outlets inside the house (and a separate independent circuit for our garage fridge), the other bigger stuff (such as the 14-50 for the model 3, AC, dryer, oven, etc) is wired directly to the main panel outside.

my question is this: can i install a 20 amp double pole breaker in that two spots that are still open in the subpanel and use that to power the LCS-20 for the volt? what do i need to look for to figure out if that's something i can do?

 

[Rocky_H]

my question is this: can i install a 20 amp double pole breaker in that two spots that are still open in the subpanel and use that to power the LCS-20 for the volt? what do i need to look for to figure out if that's something i can do?

Yes, that would be the most straightforward way to do that. Maybe the only thing to check would be doing a load calculation just to make sure you can add another 20A circuit. You can find load calculation worksheets online, but an extra 20A is usually not a big deal, so it will probably be fine.

 

[Scrannel]

Wire run through metal conduit, terminated with neutral on neutral side of box (as per all white cable,, though it's a "bonded" neutral) -- ground on it's proper side. No exposed wire at breaker, nor is breaker bolt crimping on insulation. No pics at this moment as we're getting ready for a possible second round of fires -- Malibu. Thanks

 

[crackers8199]

Yes, that would be the most straightforward way to do that. Maybe the only thing to check would be doing a load calculation just to make sure you can add another 20A circuit. You can find load calculation worksheets online, but an extra 20A is usually not a big deal, so it will probably be fine.

I've tried doing the load calcs but I'm getting stuck on the square footage and how to determine that. It literally would cover my entire house if I have to count every area that is covered by the subpanel...

 

[smashcz]

Install 14-50 outlet, 6 awg wire, 50A breaker, then just don't charge at the same time as dryer or stove

 

[Rocky_H]

I've tried doing the load calcs but I'm getting stuck on the square footage and how to determine that. It literally would cover my entire house if I have to count every area that is covered by the subpanel...

Yes, I think that is what it means.

then just don't charge at the same time as dryer or stove

@crackers8199 This is basically the easiest way to figure it into a load calculation officially so almost anyone's situation can add at least some kind of 30 or 50 amp circuit. I think it's called the "non-coincident load" provision. If you have two high amp loads that are not going to be used at the same time, like the oven and a 14-50 outlet for charging overnight, you are allowed to group those in the calculation as one load and count it as the larger of the two. So the car charging outlet would not end up being an entirely new load added on top of everything else in the house.