Thursday, November 22, 2007

Installing a dryer circuit

I spent parts of the last couple weekends installing a new 120/240 dryer circuit in my garage. When we bought the house there was only a very old gas dryer. Here are my notes and lessons learned.

Dryers need a 30amp circuit, which translates to an AWG #10 wire. The national electric code requires 4-wire installations for new circuits. The proper socket is 14-30. I used Schedule 40 PVC piping to run the circuit from the corner of the garage to the back of the panel. I used separate THHN wires (black and red for phase, white for neutral, green for ground) inside the pipe, and a 4-wire Romex cable from the junction box through the wall to the panel.

Pulling the wires through the piping is tricky and requires two people. In order to make it through and around the bends, remove an inch or two from the wire insulation and hook a cable through the hole at the end of the fishing tape, all nicely tied up with plenty of electrical tape. One person pulls the fishing tape, one person feeds the cables at the other end of the pipe. For Schedule 40 PVC the NEC requires at most 4 bends between pull locations.

It's a very good idea to get an electrician for the actual hookup in the panel, and installation of the breaker. Well worth the money.

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