It's not uncommon to want to run 120V wiring underground. You may want to send power to your shed or garage, or you may be interested in wiring up a lamp post or electric gate motor. In either case, there are a few details you'll need to be aware of in order to meet current building codes.

First off, it's not necessary to run the wiring in conduit if you follow a few basic rules:

• You must bury the wire a minimum of 12-inches below the ground (with GFCI) or 18-inches (without GFCI)
  
• If you decide on direct-burial, you must use PVC-jacketed Type UF (underground feeder) cable.
  
• You must place a GFCI on the circuit
• You must keep the maximum overcurrent protection of the circuit to 20 amps (20A breaker)

If you want to use conduit you can. Typically this will be gray PVC and can be 3/4-inch diameter for a single line. Check with your local building codes to verify whether or not you can use PVC, as metal conduit may be specified. In addition, the required burial depths may be different for each. If you use conduit, it can be sealed and you can use regular 12/2 wiring instead of direct-burial cable.

The main thing is to double check your local codes, but realize your options and take the safest, or simplest route depending on your situation. If you can get away without conduit and the wiring is in an area that isn't liable to get in the way of future digging, then direct-burial cable might be best. If you're running through the middle of your yard, then a PVC or metal conduit might be a great idea, regardless if it's required to meet code.

Nothing's better than getting much-needed power to a shed or garage, so attack this type of project with gusto and reap the benefits. As always, consult or use a licensed electrician if things seem to be beyond your level of expertise.