100 Amp Main Panel

[Hut]

I am located in Toronto, Canada.

The main electric panel is my house is only rated at 100 Amp. I am planning to install the NEMA 14-50 plug in my garage.

1. Given that I am planning to charge the Model S at night when the electric load / demand is lower. Will my 100 Amp main panel do the job or do I need to upgrade it to 200 Amp?

2. Do I need a 50A breaker or a 40A breaker for this new NEMA 14-50 plug?

Thanks!!

 

[Lloyd]

You should be OK as long as your load during charging time is 50 amps or less, which I would think it is unless you have electric heat for your house. You need a 50 amp breaker for the 14-50, and the UMC will pull 40 amps which is 80% of the rated 50 for a continuous draw.

 

[Doug_G]

1. It should be fine. To be safe you should schedule the charge for late night so you're not using the stove, dryer, etc. If you were charging and running the stove and the dryer at the same time it might start getting dicey.

2. You need a 50A breaker.

 

[Hut]

Great info! My house is heated by a natural gas furnace.

Does anyone have an idea how much to run a NEMA 14-50 receptacle from the basement to the garage?

 

[dsm363]

If they have to do a lot of work and upgrading to 200A service isn't that much more, might be worth exploring but sounds like not needed.

 

[FlasherZ]

I have very little familiarity with the CEC.

In the US, the NEC will force you to do a load calculation to determine whether you have appropriate service for your needs. If your appliances (oven/range/furnace) are all gas-based, you should be ok for the average home. If you have an electric range or dryer, load calculations are likely going to require a service upgrade with the additional load.

Upgrading service will be a rather expensive proposition (in the US, I tell others to expect about $2000-2500 for a 60-125A service upgrade to 200A) compared to running the new circuit. The cost of running a new circuit will depend upon the length of the wiring needed, protection needs (conduit vs. running through walls), special construction needs (fishing wire through walls, drilling joists for romex, etc.), and whether you have spaces free in your panel or some work needs to be done to make room.

 

[RandyS]

I'm in San Diego, but here is how the load calcs went for my EVSE installation (Blink on a 40amp breaker). I have a 125 amp main breaker for the house. It is interesting to see how the calculations work.

General loads:
2469 sq ft x 3va/sq ft = 7407 va
two small appliance circuits = 3000 va
microwave = 840 va
electric oven 8.1 kw = 8100 va
garbage disposal = 840 va
dishwasher = 1000 va
evse = 7200 va
total general load = 28376 va

first 8 kva of general load at 100% = 8000 va
remainder of load at 40% = 8154.8 va
total net general load = 16155 va

hvac load:
1 unit x 29.8A x 240v = 7152 va

total demand load:
total net general load = 16155 va
total hvac load = 7152 va

total demand load = 23307 va
23307 va / 240v = 97 amps
panel size = 125 amps

calc load is about 30 amps less than panel size. Permit issued and inspector signed off...