Post by the light works on Mar 6, 2013 20:22:13 GMT
If I'm going to add a subpanel in my garage working off of the main breaker box:
1) How may amps should it be (30 v 60)? I'll be using it for lighting in garage & shed, garage door opener, air compressor (occasional usage), & assorted power tools.
2) Do I need to switch off the main circuit before adding the circuit for the new subpanel?
3) If I've got this right, 30A requires a three wire feed while a 60A would be a four wire feed, right?
4) Last question: For the feed from the main to the sub, romex vs armored? It will be a fully inside run from the main to the garage.
Thanks!
1: for a common home garage/shop, I run 1 15A lighting circuit and 1 20A plug circuit. this will run 1 power tool at a time. however, if you are installing a subpanel; I would go ahead and go with at least 40 amps, to allow for the inevitable expansion. if there is any chance of putting in a hot tub, then go with at least 60.
2: I do not. however, you might be more comfortable doing so. if done properly, you do not come into contact with any energized components, but mistakes are possible.
3:any 120/240V combination circuit requires 4 wires (US single phase) ground MUST be separate from neutral until the original point of disconnect.
4: unless local codes require conduit, then type NM-B (romex) is acceptable as long as it is reasonably protected from physical damage. in an unfinished garage, wire run against the side of the stud is considered reasonably protected in the jurisdiction I work in - your local codes may vary.
wire sizing: basic rule of thumb: #10 gets a 30 amp breaker, #8 gets 40A and #6 gets a 50A (though a furnace can be wired with #6 on a 60A breaker as long as the furnace load is less than 60A.)