Electric Vehicle Charging Station

[Grouch1980]

Hey guys,
In a single family home, we're specifying a Tesla charging station... the cutsheet says it draws about 32 amps, at 208 volts (voltage range is from 208 volts to 250 volts). Where would charging stations get classified in NEC article 220, so one can apply a demand factor? Does a charging station count as an appliance that's fastened in place, letting one use Section 220.53 (Appliance Load demand factor section from the 2008 NEC), and use 75% as a demand factor if we have more than 4 appliances fastened in place? or are charging stations taken at 100%?

Thanks.

 

[Buck Parrish]

125 % NEC 625.14

 

[Grouch1980]

125 % NEC 625.14

Nice. Thank you.

 

[wwhitney]

125 % NEC 625.14

Not relevant for load calculations.

This topic came up recently for the optional method: https://xenforo.mikeholt.com/threads/ev-chargers-residential-load-calcs.2563111/

I haven't looked at the regular method.

Cheers, Wayne

 

[Grouch1980]

I took it as not being able to take a demand at the regular / standard calculation. 625.14 is saying it's a continuous load, so i interpreted that as not being able to take a demand factor if you use the standard calculation.

 

[wwhitney]

I was under the impression the optional calculation always made more sense for dwelling units? But you're using the 2008 NEC, not sure if it's different from the more recent versions.

Not so familiar with the standard calculation, but one could certainly argue than an EVSE is an appliance that should qualify for the 75% demand factor for 4 or more appliances.

To me, EVSEs seem like a new profile of load that ought to be explicitly addressed in 220. As that hasn't happened, you run in debate about how to categorize it. From an engineering point of view, there's a decent argument for including it at 100% in the load calculation, but that doesn't mean that the NEC requires that you do so.

Cheers, Wayne

 

[Chamuit]

... explicitly addressed in 220. As that hasn't happened, you run in debate about how to categorize it. From an engineering point of view, there's a decent argument for including it at 100% in the load calculation, but that doesn't mean that the NEC requires that you do so.

Cheers, Wayne

That's what I would do, at first glance.

 

[Grouch1980]

Hey guys,
So coming back to this topic. I'm sizing the feeder to a parking lot with about 12 EV charging stations. So the feeder (and breaker) should be sized at 125% of the total charging station load?

 

[Chamuit]

625.40 & 625.42 are all you have to guide your calls. There isn't a table like for multiple dryers, ovens, etc. yet. May need to talk to your AHJ and see their take in this.