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Multiple EVs load sharing on single circuit.

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C

Ccarlson32

Member
Location
Wisconsin
Occupation
Master electrician
Good morning, I have tried to scroll to find this scenario--but have not found.
I have a customer that is wanting to install (2) Tesla chargers on a shared circuit.

Teslas installation instructions show the optional connection for load sharing.
(One main charger, one slave charger.)

After intial thought, as long as the wiring was installed for the maximum ampacity of the breaker--this would not be an issue.

But, 625.40 says "each outlet installed for the purpose of charging electric vehicles shall be supplied by an individual branch circuit. Each circuit shall have no other outlets."

Outlet is defined as "an outlet is a point on a wiring system that supplies current to utilization equipment"

If installed a junction box with splice point to split between chargers and communication wire as tesla shows, we technically have 'two outlets' therefore would not be permitted?

I would consider a junction box NOT an outlet if I am not connecting a receptacle or switch directly to it---but I am splicing wires to connect to utilization equipment--just not directly in that box?

I have attached teslas installation for load sharing.

**Wisconsin--2017 NEC for reference**


Thanks in advance.
 

Attachments

  • load sharing documentation.pdf
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charlie b

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Semi-Retired Electrical Engineer
A junction box is not an outlet, even if it has splices inside.

But you will still have two outlets supplied by one breaker. Having them connected separately somewhere downstream of the breaker does not change the fact that each outlet does not have an individual branch circuit.
 
C

Ccarlson32

Member
Location
Wisconsin
Occupation
Master electrician
petersonra said:
Nothing prevents you from feeding two chargers from the same feeder though.
Click to expand...
So if I could tap off a the feeder to a sub panel or disconnect to achieve the same result, but cannot with a branch circuit? That doesn't make much sense.
625.40 says each outlet must be supplied by an individual branch circuit. Each circuit shall have no other outlets. So calling it a feeder doesnt really change the requirements imo.

I see the 2023 code addresses this issue with an exception as long as it has adjustable settings or load management but in a pinch until Wisconsin decides to adopt 2023 code or newer.
 
Last edited:
E

Elect117

Senior Member
Location
California
Occupation
Engineer E.E. P.E.
petersonra said:
Nothing prevents you from feeding two chargers from the same feeder though.
Click to expand...

Feeder implies it terminates at a OCPD. This doesn't.

The question is whether or not you are allowed to have more than one load on the branch circuit so long as all the wire and equipment is protected at their rating by the breaker.

While I believe the install would be safe, 625.40 implies it would be noncompliant.

To make it compliant, I think you could add a fused disconnect before each charger therefore making that splice in the feeder circuit and the branch circuit the final leg to each charger.
 
R

retirede

Senior Member
Location
Illinois
Sharing a branch circuit for EVSEs with load sharing capability is permitted starting with the 2023 NEC as long as the equipment is listed as an Energy Management System.

I don’t think the Tesla equipment is listed as such, so even if your area adopts 2023, you still have the issue. You can run a 50A feeder to a subpanel and run a 50A branch circuit to each EVSE and comply.
 
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