Shop build out, bringing over 100amps

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hamman
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Shop build out, bringing over 100amps

Post by hamman » Tue Jan 07, 2020 11:47 am

HI im remodeling an old garadge into a shop. It is roughly 10 yards from the house and main breaker box. It will have a large electric heater in addition to woodworking eqipment and a speaker system.I plan on building some guest living quarters as well so we want 100 amps. Will I need to driect bury the cable and what size cable will will be required ? Thank you !

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emtnut
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Re: Shop build out, bringing over 100amps

Post by emtnut » Tue Jan 07, 2020 11:58 am

Your general location would help, CEC and NEC differ on cable ratings.

Canada, a #1 AL cable is what you need.
As to whether you direct bury, place in conduit, or go overhead is up to you.

If you're planning on being there a long time, I'd recommend conduit and RW90 conductors (THWN)
~~ Ford Ford Ford Ford Ford Ford :mrgreen: ~~

hamman
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Re: Shop build out, bringing over 100amps

Post by hamman » Tue Jan 07, 2020 10:28 pm

I am in Oregon Usa, thank you for the reply

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Aaron
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Re: Shop build out, bringing over 100amps

Post by Aaron » Wed Jan 08, 2020 4:08 am

Pretty much the same in the US as what emtnut described above for Canada. I recommend burial. Your trench must be at least 24 inches. Call your utility locator service before digging so you don't accidentally disrupt an existing utility line.

I'd go for the 1/0 aluminum. It's cheaper and lighter, even if it's bulkier. You'll probably need 1.5" or 2" diameter pipes and ells on each end of the run into the buildings to accommodate its bulk.

Make sure it has four conductors. You're going to want a sub-panel in the outbuilding, and it will require CAFCI breakers for branch circuits serving the habitable areas. Outside receptacles must be GFCI and weatherproof rated, and have "extra duty" in-use covers. The garage area can use regular breakers. You could probably get by fine with a 12-space panel. You'll also need a couple grounding rods, make they're 1/2" diameter and at least 8 feet long.

hamman
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Joined: Tue Jan 07, 2020 11:11 am

Re: Shop build out, bringing over 100amps

Post by hamman » Wed Jan 08, 2020 11:00 am

So i would use 3 types of breakers; one outsides which will feed the sub pannel(GFCI Weatherproof rated). Then withn the subpannel box(branch circut) the ones that will be run the the shop area (CAFCI) and then the normal recpticals which will feed the lights and whatnot in ther living area. Then I will have a new grounding rod at both sides of the new branch circut? Thank you for the help!

hamman
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Joined: Tue Jan 07, 2020 11:11 am

Re: Shop build out, bringing over 100amps

Post by hamman » Wed Jan 08, 2020 11:05 am

If im using aluminum i need an aint oxidation compound i read? Its helps with expanding and contracting of the ground so that it cant come lose and arc at the ground bar?

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Aaron
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Re: Shop build out, bringing over 100amps

Post by Aaron » Wed Jan 08, 2020 2:08 pm

You'd have two two-pole 100A breakers, one for your main house panel and the other for the disconnect breaker in the sub-panel. Some panels come with main breakers preinstalled, so you may opt for that for your sub-panel. These two-pole breakers are standard, not CAFCI.

Then for the shop/garage, you can use regular breakers (neither GFCI nor CAFCI) for branch circuits powering receptacles and lights. This is because it's not habitable space.

For the habitable space, you need CAFCI breakers for branch circuits powering lights and receptacles in those areas. All these branch circuit breakers get installed in that subpanel, and you just wire your circuits where lights, switches, and receptacles are needed throughout the building.

The two ground rods will actually be driven into the ground at the outbuilding, at least six feet apart, as close to the panel as possible. They should be buried completely in the earth. You bolt #6 copper wire between the rods to the ground of the subpanel in the building using acorn clamps. This equalizes the ground potential between the ground source from the house and the ground from the outbuilding.

Yes, you do apply an antioxidant jelly to the stripped aluminum conductors before terminating them into the lugs of the panels, on both sides.

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