The right conduit to use is a liquidtight conduit approved for use underground or outside installations. It is a metal conduit covered by resistant plastic. You should find out if there is a code regarding buried electrical lines. My conduit will be buried between 18" and 24". You do not need to worry about frost lines because you are dealing with electricity and not pipes carrying water.

I bought 50 feet of conduit, more than the distance between my house and my shed. The conduit will be connected to a switch box in my basement and to a junction box inside my shed.

You will need an electrician's fish tape to pull the wire inside the conduit. If you find difficult to pull the wire there is a clear lubricant that you can use to make the job easier. Make sure that the lubricant dries before you connect the wire to the main box.

