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Grounding Receptacles in a Garage, Changing a 220 Volt Receptacle to 110 Volts and Wiring a Dimmer Switch

January 17, 2008

Doug Asks:
I am trying to update my 1960 outlets from the 2 prong to a grounded 3 prong and not having much luck. The 2 cables that go to the boxes (outlets) are three conductor (red, white , black). 2 cables go to each outlet and no ground wire is present. I believe I need to install GFCI’s but how are these wired? Currently the neutral side is easy but the black and red are both hot and the original install has the reds going to the top terminal and then the blacks going to the bottom terminal. Given this how do I wire the load and the line? Thank you, Doug

Wayne’s Answer:
It sounds like someone wired your receptacles for 2 circuits at each location. What do you have for voltage between the black and red wires?

If you don’t have an existing ground wire, then you have a few options.
1. Install a ground wire back to the ground bar in your breaker box.
2. Install a GFCI receptacle, then you may use 3 prong receptacles, but they won’t be grounded
3. Disconnect the red wire in the breaker box and make it a ground.

If you do not need 2 circuits in your garage, then I recommend option # 3. Remove the red wire from the breaker, wrap some green electrical tape around it and terminate it to the ground bar. Then go to each receptacle location and wrap some green electrical tape around the red wire and connect this to the ground screw on the receptacle.

The garage receptacles are required to be GFCI protected. It sounds like your only option to do this is a GFCI breaker. You can’t use GFCI receptacles because of the way it is wired. To use the GFCI receptacles, you need a hot and neutral coming into the box and a hot and neutral going out of the box.


Maher asks:
I have a 220 receptacle for my convection oven. I purchased a new range and it has a 110 plug. Can I replace the 220 receptacle with a 110 receptacle? if I can, how is it done? thank you

Wayne’s answer:
This can be done, but I don’t recommend doing this. I would install a new circuit for the 110 receptacle. If it is for a gas stove, you can get power from the closest receptacle. A gas stove typically only needs power for the igniter which uses very minimal power.


Toby asks:
I bought a dimmer switch it has 2 black wires coming out of the back and a green wire. I took the wall plate off and there is a black and white wire how do I hook the dimmer switch?

Wayne’s answer:
If there is only a black and white connected to your existing switch, then the first thing you need to do is correct the previous person’s mistake that wired the switch. In a switch in a residential application is the only time a white wire can be used as a hot wire. However, the white wire needs to be identified as a “hot” wire and it must be the power supply. To identify it as a hot wire, you need to either mark it with a black permanent marker or wrap black electrical tape around it.

Now just connect the green wire from the dimmer switch to the bare copper wire in your switch box. Next connect one of the black wires from the dimmer switch to the black wire in the switch box. Finally, connect the other black wire from the dimmer switch to the white wire that you just identified as a “hot” in the switch box.


Safety Tip to Everyone:
Make sure you turn off the power before working on any electrical circuit.

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5 Responses to “Grounding Receptacles in a Garage, Changing a 220 Volt Receptacle to 110 Volts and Wiring a Dimmer Switch”

  1. dave biden on January 27th, 2008 5:21 pm

    i recently removed old outlet and discovered 4 wires and would like to instal a gfci but have noticed no power to outlet and light is off outside

  2. sheila on February 8th, 2008 7:04 pm

    We have a 220volt well pump, Wire 12-3 with a ground. I would like a receptacle at the well house. Can we make a 220 to a 110volt.? If so? How. Thanks, Ray & Sheila

  3. Don Saltzman on November 15th, 2008 12:30 pm

    I’m attempting to wire high bay lights that I purchased used. The wire coming out of the panel is 10/3 on a 30 amp breaker. I have five leads coming out of the lamps, “common”, 120 volt, 208 volt, 240 volt and 277 volt. The 10/3 has red, black, white and ground. Which of the 10/3 leads gets wired to the leads exiting the lamps?

  4. John Reiss on March 24th, 2009 5:40 am

    I have a 220v well away from my house. The water softner need a 110 volt source to power it. How can I wire 110v off of the 220v pump switch?

  5. robert jones on May 26th, 2011 8:01 am

    I want to know if I can take an existing 220 plug and come off of one side of the 220 line and hook up a 110 plug?