EV Chargers on 400A

[TriednTrue]

Hi everyone,

I have a calculations question. If you have a 400A 3-phase 120/208V panel dedicated to EV chargers, how many 2-pole 40A circuits can you install?

Thanks

 

[ron]

(12) 40A 2-pole chargers since EV chargers are continuous loads, unless you can network them together to reduce load demand

40	40
	40	40
40		40
40	40
	40	40
40		40
40	40
	40	40
40		40
40	40
	40	40
40		40

 

[wwhitney]

(12) 40A 2-pole chargers since EV chargers are continuous loads, unless you can network them together to reduce load demand

But the OP asked for 40A circuits, not for circuits for 40A continuous EVSEs. So presumably the OP is installing 30A or 32A continuous EVSEs.

If so, the answer is 16: (3) 40A circuits in a balanced configuration give a line demand of 40A*sqrt(3) = 69.3A. 5 of those balanced sets, or 15 circuits, give a line demand of 5 times as much, or 346.4A. And then one more will boost the line demand on two lines to 386.4A.

Now if these are really 30A EVSEs on 40A circuits, then the demand is smaller by a factor of 30/32, so the answer becomes 18.

Cheers, Wayne