rewiring garage

[KenC]

I plan to rewire my detached garage, to distribute outlets to locations that actually make sense (as opposed to six outlets along one wall, and NONE anywhere else). It is, for the moment, uninsulated with cinderblock side walls and exposed plywood roof decking at the peaked ceiling. Just wondering what specs of cable I should be using, since the cables will be exposed. We don't use the garage for cars - I'm setting it up as a workshop.

[kactuskid]

If you are installing a completely new wire cable from your main panel in the house to supply power to a detached garage then a 20 amp circut is the maximum size you can install unless you want to install a sub panel in the garage that'll provide you with greater than 20 amps of power. A 12-2/G gauge cable must be protected by a 20 amp breaker and will provide you 2400 watts max..

What tools do you want to run out there, what is the amp or wattage load of each? Add them up and if they'll exceed 20 amps then you'll need the sub panel. You will then need to install a ground rod at the detached garage and install the appropriate gauge wire depending on the service you install.

If you have no wall studs then you'll need to install THHN/THWN wires in conduit and surface mount the conduit on the cinderblock using tapcon screws. All readily accessible receptacles are required to be GFCI protected in your garage.

Here's a link that'll give you some things to consider, ask back with more questions.

http://www.woodworking.com/ww101wire.cfm

[KenC]

Thanks for the link.

Actually, there is currently a sub panel in the garage. Excuse the amateurish description, but here’s what I have. The feed to the garage splits off the from main panel in the house, and goes via underground conduit over to the garage, where it comes up through the floor slab and enters the first of two boxes. This first box has a giant ON/OFF lever, and inside are two 60 Amp fuses. Cables exit this box and lead to the second box, about a foot away, which has four fuses in it. The cables leading to the various outlets and light fixtures all come from this second fusebox (two 15’s, a 20 and a 30).

Short-term, I need to reroute some existing cable (for light fixture) that will interfere with the installation of a new garage door in a couple weeks, and install a new outlet on the ceiling to power the garage door opener. I assume simple 14-2 wire will be OK for that use, and that I can simply tie in to an existing outlet. That is the temporary fix.

Long-term, I’m planning to redistribute and increase the number of outlets for more practical layout, improve the lighting, and replace the 4 - fuse box with an 8 slot breaker box. I don’t currently have a dust collector system (240V), but I may add one in the future. My current table saw is a light-weight, but I will be replacing it with a decent saw, which might prefer 240V supply as well.

Other stationary power tools, and hand-tools for that matter, would rarely be operated simultaneously, so the draw at any given moment shouldn’t be so high that I’d need separate circuits for each tool. (???)

The guy at Home Depot suggested I use either metal or PCV conduit for any wiring tacked to the block wall, and simple plastic sheathed cable can be exposed along the ceiling.

Whatdya think?

[kactuskid]

Well it sounds like you have a 60 amp subpanel then. Is this panel grounded, there needs to be 2 ground rods driven in the ground at the garage. Is it a 3 wire or 4 wire feed from your house panel? Is this feed cable from the house protected at the house by a breaker or is it a direct feed to the 60 amp disconnect.

If you decide to use any 14 gauge wires it needs to be connected to ONLY the 15 amp circuit. Use 12 gauge for the 20 amp circuit. The garaged door opener recpetacle doesn't need to be GFCI protected as long as its 7' above floor level.

You really need to buy a good book on electrical wiring. The Black and Decker home wiring book is a good start. You also need to check with your local codes as to what's allowed for a new breaker panel in this garage, alot of how a new sub panel should be wired will depend on the answer to the questions asked above.

Here's also an excellent link that'll give you tons of info of how this should be done depending on if the feed from your main panel is 3 wires or 4 wires.
http://www.selfhelpandmore.com/homew...rage/index.htm