Electrical Vehicle Charging Station | Load calc

[Aru]

Please advise. I do not have a lot of experience designing EHV charging station.

Our client is adding a new car weather testing station. They expressed interest in adding new EHV charging as well - following items were what they shared. We will have to upsize the existing utility transformer so I am trying to find the overall load for the EHVs. My understanding is that the EHV charging station will get plugged into the NEMA 14-50 outlets. So, I am not understanding why they have 2 outlets vs 4 to 6 charging stations. Am I missing something here? Do I treat these 3 items as separate loads?

1. (2) of NEMA 14-50 outlets each not more than 10kW.
2. (4) to (6) Level 2 EHV charging station with a max capacity of 50A (~20kW) for each station.

I am probably being ignorant here but please educate me.

 

[retirede]

The info is sketchy at best. You need to get specs on the equipment they plan to use. Since EV charging is a continuous load, the branch circuits must be sized at 125% of the equipment rating. Max size would be a 40A unit plugged into a 14-50. A 50A unit would need to be hardwired on a 65A circuit. Most of this size are actually 48A allowing a 60A circuit.

Other points:
Each EVSE (commonly called “Charger”) must be on its own branch circuit.

If the EVSEs have load sharing capability, the maximum load for feeders and services can be calculated using the reduced load as limited by the load sharing schema.

 

[wwhitney]

So, I am not understanding why they have 2 outlets vs 4 to 6 charging stations. Am I missing something here? Do I treat these 3 items as separate loads?

I read item (1) and item (2) to be entirely separate. So the receptacles with the associated max loads, plus (4) to (6) fixed installation charging stations.

Cheers, Wayne

 

[retirede]

I read item (1) and item (2) to be entirely separate. So the receptacles with the associated max loads, plus (4) to (6) fixed installation charging stations.

Cheers, Wayne

Likely so. If true, the 14-50s count as 9600W each, but we still need to know if the hard wired units perform load sharing. Otherwise, they have to be counted at 15 KW each!