Breaker for new Garage charger.

[Ndgame]

I am sure this has been hammered to death in the forums but my searches aren't finding much of supportive information onit.

So I purchased the Chargepoint Home Flex Level 2 48 amp charger. The charger is designed to use only 80% of whatever amp breaker you tell it that you put in. So for me to get the full 48 amps of charging in theory I would need a 60 amp breaker.

Now with that said I know a 6/3 is only rated at 55 amps and if I was actually pulling 60 amps that it would not work, but with me only pulling 48 amps or 50 amps max if I switch chargers down the road is it ok to use 6/3 with a 60 amp breaker but only using 50 or less amps?

Thanks,
AH

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[Maquis]

6/3 MC or SER is good for 60+. Just not NM (no, you can’t use it and meet code).
The branch circuit for an EVSE must be sized at a minimum of 125% rated current. That’s why you need a 60A circuit for a 48A EVSE.

Another option is to use a 50A breaker and commission the ChargePoint for 40A.

 

[flapjake314]

Another option is to use a 50A breaker and commission the ChargePoint for 40A.

yeah i came here to say this, i don't own the chargepoint but i think virtually all these chargers can be down-rated and may even do so automatically... if you're somehow not able to do a 60A breaker you're not forced to, you'll just charge at a lower speed

 

[Ndgame]

Thanks everyone. So I have 1 more question. When I look at 6/3 MC cable it is showing 4 wires (black,red,white, and green) however when I look at 6/2 MC able it is 3 cables (black,white, and green). So it apprears that the 6/2 3 wire MC is what I want correct?

 

[voerman]

Thanks everyone. So I have 1 more question. When I look at 6/3 MC cable it is showing 4 wires (black,red,white, and green) however when I look at 6/2 MC able it is 3 cables (black,white, and green). So it apprears that the 6/2 3 wire MC is what I want correct?

I assume you will get many answers but here goes:

The charger when hard wired (at least all the ones I have heard of) only need three wires, 2 hot and one ground. The white wire in the 6/3 cable is for a neutral which your charger does not use. When you wire the charger (with 6/2) be sure to tape over the white wire with black or red tape both in the panel box and in the charger. This tells anyone who might look that the white wire is being used as a hot wire and is not a neutral. The black wire is the other hot and the green one is ground. This is standard practice for wiring chargers and other appliances which are hard wired and do not require a neutral.

Of course, the two hot wires need to be connected to the two poles on your 240 volt breaker. Be sure to connect the ground wire to the ground bus, not the neutral bus if they are separate in your panel box (they may or may not be depending on whether it is a main or subpanel).

Hope that was not too confusing.
Lou

 

[Mach-Lee]

Thanks everyone. So I have 1 more question. When I look at 6/3 MC cable it is showing 4 wires (black,red,white, and green) however when I look at 6/2 MC able it is 3 cables (black,white, and green). So it apprears that the 6/2 3 wire MC is what I want correct?

You only need 6/2 for the charger. 6/3 is a waste.

 

[House MD]

I installed ChargePoint with 60a breaker, 6awg THHN, and I'm running it at 48a.

Do not use Romex/NM for the charger, they are only rated for 55amps.

 

[Maquis]

yeah i came here to say this, i don't own the chargepoint but i think virtually all these chargers can be down-rated and may even do so automatically... if you're somehow not able to do a 60A breaker you're not forced to, you'll just charge at a lower speed

They cannot detect the breaker size. Some have a physical switch that must be set, some ask you the breaker size during setup in the app. The second case is as close to automatic as it gets.

 

[flapjake314]

They cannot detect the breaker size. Some have a physical switch that must be set, some ask you the breaker size during setup in the app. The second case is as close to automatic as it gets.

i have the tesla one and it detects on its own. maybe you have specific knowledge of OP's chargepoint unit though

 

[Mach-Lee]

i have the tesla one and it detects on its own. maybe you have specific knowledge of OP's chargepoint unit though

No, the Tesla ones don't either. It has to be set in the WiFi portal during setup. It's impossible to auto-detect breaker size, a human has to enter it at some point.

 

[RickMachE]

I had my electrician wire the circuit with 4 conductor wire, even though we were hardwiring and only needed 3. That way, if a 14-50 outlet is ever desired in the future, everything is ready for it.

 

[Hammered]

i have the tesla one and it detects on its own. maybe you have specific knowledge of OP's chargepoint unit though

Yeah, not how it works. Tesla has some very poor wording in their manual and some foolishly believe it's "automatic". They really need to correct that. That's referring to if there's multiple EVSEs, each on their own circuit breaker, you can tell them the MAX power that can be pulled from all of them. Say if there's 3x 48a EVSEs, they can be told to never pull more than 100 amps and that 100 amp bucket will be shared between all 3 units ala "automatic load management".

 

[Fremont Kid]

Cost compared to 3 wire vs 4 wire is fairly minimal considering 4 wire cable will future proof your setup. I have 4 wire AWG6 both for my Mach-e charger and for a new induction cooktop/oven. 50A circuits for both.

 

[flapjake314]

Yeah, not how it works. Tesla has some very poor wording in their manual and some foolishly believe it's "automatic". They really need to correct that. That's referring to if there's multiple EVSEs, each on their own circuit breaker, you can tell them the MAX power that can be pulled from all of them. Say if there's 3x 48a EVSEs, they can be told to never pull more than 100 amps and that 100 amp bucket will be shared between all 3 units ala "automatic load management".

i own and commissioned the tesla charger. i have 50A breakers even though the charger is capable of using 60A breakers. when i turned it on for the first time it automatically selected 50A.

i even purposely TRIED to switch it to 60A (long story, but i was trying to test whether anyone could mess it up) and the answer is no, the charger did not let me select 60A.

 

[shelnian]

It meets code to use 6/3 connected to a 60A breaker. Hardwired 6/3 doesn't require a GFCI breaker like a 14-50 would.

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