EV Charger and Noncoincident loads

[jsieczko]

I have a code question on EV Chargers and Non-coincident loads.

There is a subpanel in a non-dwelling detached garage. It’s fed by 3 AWG on an 80 amp breaker. Other than some lights and receptacles, the subpanel's main load is a Tesla Gen2 Supercharger on a 70 amp breaker, which will run a continuous load of 56 amps (80%) when charging.

I want to install a 7500 Watt heater on the same panel (40 amp breaker / 31.25 amp expected load).

The heater and supercharger will not be used at the same time. (Obviously, this would exceed the max load.)

Can I consider the EV Charger and heater a Non-coincident load under 220.60?

Unlike a heater and A/C, someone could attempt to run both at the same time.

 

[HEYDOG]

No! You cannot treat it as a non coincidental load!

 

[electrofelon]

It's not cheap, but what about installing a DPDT switch? Also I think there are some EV load management switchers out there.

 

[jsieczko]

I was considering a breaker interlock ( https://www.eaton.com/us/en-us/skuPage.BRML.html ), so only one of the two breakers (either the 40 Amp or 70 Amp) could be switched on at once.

 

[retirede]

If you’re on the 2020 NEC or later, the easiest solution would be to deprecate the EVSE to a lower setting as allowed by 625.42.

 

[electrofelon]

I was considering a breaker interlock ( https://www.eaton.com/us/en-us/skuPage.BRML.html ), so only one of the two breakers (either the 40 Amp or 70 Amp) could be switched on at once.

I don't see why that wouldn't be acceptable

 

[winnie]

It cannot be considered a non coincident load unless so aspect of the design or operation makes it non coincident.

A breaker interlock would do that manually.

Some EV chargers have dynamic power management capabilities, and dial back their output when other loads are operating. IMHO this also qualifies as non coincident.

Jon

 

[Fred B]

Some EV chargers have dynamic power management capabilities, and dial back their output when other loads are operating. IMHO this also qualifies as non coincident.

An energy management system can be set up to control whichever loads you would like to limit to bring you below the threshold of the panel feeder
2023 NEC-625.42(A) Energy Management System (EMS).
Where an EMS in accordance with 750.30 provides load management of EVSE, the maximum equipment load on a service and feeder shall be the maximum load permitted by the EMS. The EMS shall be permitted to be integral to one piece of equipment or integral to a listed system consisting of more than one piece of equipment. When one or more pieces of equipment are provided with an integral load management control, the system shall be marked to indicate this control is provided.

 

[retirede]

The gen 2 Tesla does not have energy management capabilities, IIRC.

 

[Fred B]

The gen 2 Tesla does not have energy management capabilities, IIRC.

There are add on energy management systems, similar to load shedding.

 

[retirede]

There are add on energy management systems, similar to load shedding.

Yep - it’s only (the customer’s) money.