Level 3 EV Chargers

[Grouch1980]

Hey guys,
I attached an excerpt from the 2017 NEC handbook, section 625.42 for EV chargers. Where I highlighted in blue, for level 3 chargers... is this saying the charger load is or is not considered a continuous load? The paragraph above it, for level 2 chargers, explicitly sends you to section 625.41, where it states OCPD's are sized at 125%. But the section that I highlighted for level 3 doesn't send you to 625.41, but rather seems to be keeping it open ended / vague. I need help in interpreting this.

 

[augie47]

The Section you highlighted looks like it appears in the Handbook and not the actual NEC.
IMO, The 2017 NEC 624.41 ad 625.42 appear to requires the 125% regardless.

 

[Grouch1980]

The Section you highlighted looks like it appears in the Handbook and not the actual NEC.
IMO, The 2017 NEC 624.41 ad 625.42 appear to requires the 125% regardless.

Yes, the section I highlighted is from the handbook. I do agree... it appears level 3's require the 125% as well... it just doesn't make sense the way they wrote this... for level 2's, refer to section 625.41. For level 3's... no mention of it. Some uniformity would help.

 

[kingpb]

I don't see how, operationally, that Level 3 could be considered anything but continuous.

 

[Grouch1980]

I don't see how, operationally, that Level 3 could be considered anything but continuous.

Well, a Level 3 charger is done charging your car in what... 20 or 30 minutes? So doesn't that imply the charger is on for less than 3 hours, making it a non-continuous load? I accept that it's continuous though, due to what the NEC says.

 

[kingpb]

In the OP, there was no mention of Car. It was simply stated as Level 3. It is unlikely that a LEVEL 3 would be installed in a residence, mostly due to high cost of install. Typically, level 3 are roadside charging or Buses, or large EV's which would have engineered solutions to effectively feed multiple Level 3 in one location. In those instances, I am seeing the design be based on Level 3 as continuous.

 

[wwhitney]

If it weren't for 625.41, then DCFC (L3 chargers) would not be considered a continuous load. I think a typical unit can put out say 250V - 500V DC, matched to the battery voltage as it charges, up to some maximum current limit. E.g. a nominal 100 kW charger can put out at most 200A, and if your particular EV's battery has a voltage range of 300V - 400V, at a low state of charge the charger could provide at most 60 kW to the battery.

So charging power will slowly increase in the initial current limited portion of the charge curve, then eventually the EV BMS will start to throttle down the allowable current and charging power will decrease as the battery get fuller. That's not the power usage profile of a continuous load.

Cheers, Wayne