michael wright
New member
- Location
- Irvine, CA
Hello to all,
I have been in the business of selling and installing level 2 EVSE's for 2 years. They operate continuously at a max of 7.2 KVA or 32 amps. Generally, they are installed on 208-v, 40-amp, 2 pole service operating at 30-amps, with #6/8 THHN, depending on conduit fill and distance.
The topic has come up pretty frequently concerning diversity factors applied to multiple continuous loads when loading a panel. I almost always have to tap a 480-volt source as very few commercial facilities have adequate 120/208-volt. My go-to solution for multiple units has been a 45 kVA/125-amp, 3 ph panel for 4 total EVSE's, a 75 kVA/225-amp, 3 ph panel for 8, and a 112 kVA/400-amp, 3 ph panel for 12.
I now have some installation requests for up to 20 units that we are having discussion with concerning diversity. As defined by Art 625.40, these continuous loads need support from an OCPD of 125%. the client is arguing that the likelihood of having all drivers plugged in at the same time is minimal, and therefore is stating that they will have their E/C install a 150 kVA tfmr and 400-amp panel with 20 forty amp 2 pole breakers. My argument is that NO AHJ will recognize diversity applied the way you load calc a residential unit to continuous loads such as EV chargers. Moreover, the likelihood (IMHO) of all 20 being in use is actually very high, considering most drivers will return after work and plug in at nearly the same hours.
My solution I am putting together is an Orwellian task; a 225 kVA tfmr bus tapped to a MS of 1,200 amps and has no space, 600-amp load center (it does exist) and monster paralleled secondary conductors of around MCM 400. Anyone have any related experience in engineering these types of loads.
Best,
MW
I have been in the business of selling and installing level 2 EVSE's for 2 years. They operate continuously at a max of 7.2 KVA or 32 amps. Generally, they are installed on 208-v, 40-amp, 2 pole service operating at 30-amps, with #6/8 THHN, depending on conduit fill and distance.
The topic has come up pretty frequently concerning diversity factors applied to multiple continuous loads when loading a panel. I almost always have to tap a 480-volt source as very few commercial facilities have adequate 120/208-volt. My go-to solution for multiple units has been a 45 kVA/125-amp, 3 ph panel for 4 total EVSE's, a 75 kVA/225-amp, 3 ph panel for 8, and a 112 kVA/400-amp, 3 ph panel for 12.
I now have some installation requests for up to 20 units that we are having discussion with concerning diversity. As defined by Art 625.40, these continuous loads need support from an OCPD of 125%. the client is arguing that the likelihood of having all drivers plugged in at the same time is minimal, and therefore is stating that they will have their E/C install a 150 kVA tfmr and 400-amp panel with 20 forty amp 2 pole breakers. My argument is that NO AHJ will recognize diversity applied the way you load calc a residential unit to continuous loads such as EV chargers. Moreover, the likelihood (IMHO) of all 20 being in use is actually very high, considering most drivers will return after work and plug in at nearly the same hours.
My solution I am putting together is an Orwellian task; a 225 kVA tfmr bus tapped to a MS of 1,200 amps and has no space, 600-amp load center (it does exist) and monster paralleled secondary conductors of around MCM 400. Anyone have any related experience in engineering these types of loads.
Best,
MW