Installing wiring for a welder or air compressor is not as hard as you may think. Whether you are installing a new outlet or moving your existing 220 outlet to a new location this article will help you wire the outlet and breaker in the electric panel.
Current building codes require 220 outlet inslations to have a 4 wire cable, 2 hot wires, 1 neutral and a ground.
Dryers use a 10/3 wire and a 30 amp 220 volt breaker in the electrical panel. Check with the power requirements of your welder or air compressor to make sure that the wiring is sufficient for the power needed.
Dryers: When planning the new location of your dryer be sure to consider the length of the dryer vent and the length of dryer cords. Dryer vents can be up to 14 feet with 2 90 degree bends. If you need more bends then you must deduct 2' for each additional bend. The wiring for a dryer and the dryer outlet must be located close to your dryer location because the pig tails on most dryers are only 4' to 6' long.
In this article, you will find information about:
New Construction: If you are working on a wall that is unfinished, like an unfinished workshop shed or studio shed you will simply attach the new electrical box to a wall stud.
Existing Construction: If you are wiring the outlet on a finished wall with drywall then you will need to locate the stud closest to your desired outlet location and cut a hole in the drywall large enough to install the outlet wall box. After the box location is determined you will need to fish the wire thru the wall to the breaker panel. It is usually easiest to go down thru the floor into the floor joists under the shed floor or through the attic and down into the top of the wall plates..
Install a electrical box that is made and rated to be used with the 30 amp outlet or the size of outlet you are using. These larger boxes should have a cable clamp attached to the box to clamp the new wire coming into the box.
Current codes require a 4 wire cable (line 1, line 2, neutral, and ground), to be installed for 30 amp dryer circuits. This is called a 10/3 cable, the ground wire is not named in the name. Dryers use a 30 amp 220 volt circuit breaker and a 30 amp cable requires a 10 awg cable.
There are 4 wires used to wire a 30 amp dryer circuit. The circuits require a #10 4 wire cable, Red, Black, White and Green. The Red and Black wires are interchangeable between the two side terminals on the outlet.
Red And Black Wires: The red and black wires go to the terminals on the sides of the dryer outlet. These two wires are interchangeable between the left and right sides. It does not matter which side they are on but they cannot go to the ground or neutral terminals.
White Neutral Wire: The neutral wire is white and must go to its terminal on the back of the outlet. The white wire goes to the neutral terminal which is the center terminal on the bottom of the outlet. The neutral terminal is usually labeled "white" or "neutral"
Green or Bare Copper Wire: Ground wire goes to the center terminal on the top of the outlet. The ground is usually labeled "ground", "gnd" or "green".
Bring the new cable into the main electrical panel by doing the following:
Note: Your shed may have an electrical panel in the shed that you can use or the new cable may need to go outside the shed to the nearest panel. If you go outside and underground you should run the wire through conduit.
Make Sure You Have Space For The New Dryer Circuit In The Breaker Panel: The 30 amp breaker in the electric panel that will feed the new circuit will take up two slots in the electric panel. If there is only one slot or no slots open you will need to add slots by removing two existing single pole breakers and installing slim breakers that allow for two circuits per single slots in the panel. This will give you the extra space you need to install the breaker for the dryer.
Safety Note: Working with electricity is very dangerous and can kill you. Before working on the main electrical panel you must turn the power to it off for safety. Turn the power off by turning the main circuit breaker feeding the panel to the off position. Remove the face of the panel and double check that there is no power in the panel using a electrical tester.
Neutral Wire, White: Remove 1/2" of the wire insulation from the white neutral wire and attach it to the neutral bus bar.
Ground Wire, Green Or Bare: Remove 1/2" of the wire insulation from the green ground wire and attach it to the ground bus bar by installing it into one of the lugs and tightening the lug onto the wire.
Red Wire: Remove 1/2" of the wire insulation from the red feeder wire and attach it to one of the lugs on the new circuit breaker. (sometimes this wire is black with a red stripe on it)
Black Wire: Remove 1/2" of the wire insulation from the black feeder wire and attach it to the remaining lug on the new circuit breaker.
Install the new feeder breaker into the main electrical panel by hooking the tabs on the bottom of the breaker onto the lip in the panel and pressing the other end of the breaker onto the bus bar. Before installing the cover on the panel you may need to remove a face plate knock out so the breaker will fit thru the face of the panel cover. After removing the knock out make sure the new breaker is in the off position and replace the cover by screwing it on.
Turn the main breaker that feeds the main electrical panel on and then turn on the new 30 amp breaker. Test your new outlet by inserting your proximity tester into the outlet. You are now ready to use your new 30 amp breaker in your backyard shed!
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