Electric Cars

[jbolen]

What is the NEC load calculation for a Tesla electric car ? What be the standard wire size and overcurrent device ?

 

[curt swartz]

There is no standard. There an multiple options.

What is your profession?

 

[jbolen]

There is no standard. There an multiple options.

What is your profession?

Master Electrician

 

[pv_n00b]

It's all in NEC 625.

 

[don_resqcapt19]

It's all in NEC 625.

How is it all in 625? It appears that the load would be calculated per 220.14(A) unless adjusted by an automatic load shedding system as provided for in 625.42.

In any case the load is based on the specific charging unit that will be installed. There is no generic provision for an electric car charge in the NEC at this time.

 

[pv_n00b]

I'm not sure what version of the NEC you are using, EV charging is a newer addition so if you are looking at the 2011 or earlier NEC then you are correct, it did not provide much guidance. The 2017 and on NEC is pretty robust though. Those are the versions I am referring to.
NEC 625 describes how to design the electrical system to supply an EV charging station. Chapter 6 sections of the NEC are there to modify the based chapters 100-400 for special equipment like EV chargers, PV systems, etc.. So 625 takes precedence over 220.14(A). Part III of 625 covers the installation of EV chargers and how to design the branch circuit.

 

[wwhitney]

So 625 takes precedence over 220.14(A). Part III of 625 covers the installation of EV chargers and how to design the branch circuit.

I don't see anything in (2017) Article 625 that modifies or conflicts with 220.14(A), what am I missing?

Cheers, Wayne

 

[pv_n00b]

625.40 through .47 provides requirements for the number of branch circuits allowed, over current protection requirements, continuous duty rating requirements, disconnecting means, etc. It's way more and the little blurb in 220.14(A). If someone looks at the charger label for the load amps and uses 220.14(A) to design the branch circuit they are using the NEC incorrectly. This is such a basic concept I can't say anything else about it.

 

[wwhitney]

Yes, it says that each EVSE needs to be supplied by an individual branch circuit, and that EVSEs are continuous loads for branch and feeder sizing. The latter informs the application of 215.2 and 210.19. But I don't see any effect on 220.14(A), you still add each EVSE to the load calculation at its rating (which should include the "dialed-down" current setting if applicable).

Cheers, Wayne

 

[don_resqcapt19]

625.40 through .47 provides requirements for the number of branch circuits allowed, over current protection requirements, continuous duty rating requirements, disconnecting means, etc. It's way more and the little blurb in 220.14(A). If someone looks at the charger label for the load amps and uses 220.14(A) to design the branch circuit they are using the NEC incorrectly. This is such a basic concept I can't say anything else about it.

The load calculation is still based on the requirement in 220.14(A) and there is nothing in 625 that changes that, other than the case where the EV changer has load control equipment and the load is permitted to be calculated based on the load control setting. Sure there are installation rules specific to EVs in 625, but this question was about the load calculation and that is in 220.