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

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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