sub panel in garage - how many amps?

wombosi · 02-06-2009, 09:20 PM

I recently had a new 200amp service installed at my house.
the garage still has a subpanel, with just one 15amp fuse in it.

i want to rewire the entire garage with a sub breaker panel.
not sure how big to make it.

40amp? 60?

Basically just running power tools. I have a table saw which probably draws the most amperage and I may put an outlet for that on a separate circuit.

I'm barely using anything in the house right now, but I want to do this in such a way as to have plenty of options down the road for both places (maybe someday someone will want to charge an electric car out there, for example?).

Thanks.

jamiedolan · 02-06-2009, 10:20 PM

Quote:

Originally Posted by schmolze

I recently had a new 200amp service installed at my house.
the garage still has a subpanel, with just one 15amp fuse in it.

i want to rewire the entire garage with a sub breaker panel.
not sure how big to make it.

40amp? 60?

Basically just running power tools. I have a table saw which probably draws the most amperage and I may put an outlet for that on a separate circuit.

I'm barely using anything in the house right now, but I want to do this in such a way as to have plenty of options down the road for both places (maybe someday someone will want to charge an electric car out there, for example?).

Thanks.

Run large PVC conduit, it's cheap, and make an upgrade very easy. I don't know what an electric car would to charge it up, but I'd imagine it could use a hefty amount of power if it was going to charge up quickly.
That in mind, I'd run 1-1/4" or 1-1/2" PVC (buried).
For now a run of 8 gage thhn in conduit for 50a service would likely be more than enough.
Jamie

Scuba_Dave · 02-06-2009, 10:36 PM

The electric car idea is a pretty good example
I'm going with a 100a panel in my garage
I only want to run wire once

ZAP Fast Charger:

Quote:

It connects to a 240-volt, 60 amp circuit or 208-volt, 3-phase, 50 amp circuit.

But they also want people to be able to charge from a normal household outlet:

Quote:

A normal household 120-volt outlet typically has a 15-amp circuit breaker, meaning that the maximum amount of energy that the car can consume is approximately 1,500 watts, or 1.5 kilowatt-hours per hour. Since the battery pack in Jon's car normally needs 12 to 15 kilowatt-hours for a full recharge, it can take 10 to 12 hours to fully charge the vehicle using this technique.

PaliBob · 02-06-2009, 11:27 PM

When I rewired my house in the late 1980's I put in two 90 Amp SquareD load Centers. One at the rear of the house and another for the attached garage. Both are fed by their own 70 amp two pole breakers in the main panel.

It's really nice to have 220 in the Garage although the original reason was to power up a Radial Arm Saw. Now an Antique.