Building permits for new EVSE instalation

[Schreibdave]

I am contemplating my first EV and I was thinking about how I would install the EVSE. My son who is an electrician tells me that in order to get a building permit for the new 240v circuit I would need to do a "load calculation" on my existing service panel to confirm that I have enough current coming into the house to supply all the things I already have running plus the new EVSE. Assuming I did the calculation correctly, I will be cutting it close if I add a new 50amp circuit and the building inspector might not approve my permit.

So I did some reading and I think I have a work around to the building permit issue. Lets say I do this load calculation and it shows that I have 20 amps to spare before overloading my panel. So what I could do is apply for a permit for a new 20 amp, 240v circuit and tell the inspector that the EVSE will be set to pull less than 20 amps. Once the installation is approved I could swap the 20 amp breaker for a 50 amp breaker and program the car to only draw 20 amps during the day but 40+ amps after midnight when only my furnace or AC are running.

Does anyone have any experience with trying to make the building inspector happy when the load calculation indicates that the service panel can not accept another 50 amps of current draw? Thanks

 

[electriceddy]

I am contemplating my first EV and I was thinking about how I would install the EVSE. My son who is an electrician tells me that in order to get a building permit for the new 240v circuit I would need to do a "load calculation" on my existing service panel to confirm that I have enough current coming into the house to supply all the things I already have running plus the new EVSE. Assuming I did the calculation correctly, I will be cutting it close if I add a new 50amp circuit and the building inspector might not approve my permit.

So I did some reading and I think I have a work around to the building permit issue. Lets say I do this load calculation and it shows that I have 20 amps to spare before overloading my panel. So what I could do is apply for a permit for a new 20 amp, 240v circuit and tell the inspector that the EVSE will be set to pull less than 20 amps. Once the installation is approved I could swap the 20 amp breaker for a 50 amp breaker and program the car to only draw 20 amps during the day but 40+ amps after midnight when only my furnace or AC are running.

Does anyone have any experience with trying to make the building inspector happy when the load calculation indicates that the service panel can not accept another 50 amps of current draw? Thanks

20A circuit = 12 AWG wire, 50 A circuit = 8 AWG wire, swapping the breaker is not the way to go. If you ran 8 AWG wire (or 6 AWG as I recommend), and protected it with a 20A breaker, the inspector would read through this quite clearly, and not pass based on the fact you mentioned above.

When doing a service load calculation (or even feeding an EVSE when the calculated load is adequate), the ampacity requirement is to allow for the maximum current the equipment (EVSE in this case) is rated for.

There are alternates such as an electric vehicle management system (EVEMS), however the cost to install and purchase that equipment may be equal to or more than upgrading the main electrical service itself ( ie upgrading from 100A to 200A).
Fortunately, your son can do the work under your own permit (homeowner), without financial compensation, which will save you a lot in labor, so I would just upgrade the service.
At least that is the regulation here in B.C.
BTW...it is an electrical permit required, not a building permit