Installing Subpanel in detached garage

[bamaboy]

I am going to be installing a 100 amp subpanel in my workshop in my garage. The garage is detached but is located about 5 feet from the outside main panel attached to my house. Do I just need to install a double pole 100 amp breaker in the main and run #4-3 THHN? Or what direct burial wire or wire/size conduit do I need? Although it is a detached garage but only maybe 5 feet from the main do I have to have another ground buried at that subpanel? Even if it is by code to bury it, if I don't what are the safety concerns? Is the buried ground just for lightning? If a power tool or something shorts will it not be grounded at the subpanel? The green screw needs to be removed from the subpanel, right? Do I just run #12-2 to all my outlets from the sub panel? The garage is closed in and about to be insulated/moisture barriers installed if that help in determining whether I use indoor #12-2.

 

[Zeke]

https://www.google.com/search?q=sea...=search+garagejournal.com:+sub+panel&safe=off

 

[pattenp]

For 100A you need to use #3 Cu or #1 Al. The detached garage needs its own ground rod(s). The bonding screw does need t be removed in the sub-panel because the neutral is not to be bonded to the ground. Also if the panel has more than six breakers you need to have a main disconnect. The easiest thing is to use a main breaker panel in the garage. Use regular 12-2 Romex for 20A outlet circuits. You just add the 100A breaker in your main for the feeder to the garage. Think of it as a big branch circuit. Be sure to use 4 wires; 2 hots, 1 neutral and a ground. A good choice for under ground is 2-2-2-4 Al Mobile Home Feeder placed in 2" PVC conduit fed using a 90A breaker.