Hot Topics: Wiring Mysteries Behind the Wall

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In a perfect world, wiring diagrams, color coding and instruction manuals make installing a new switch or outlet a simple project. But whoever did your original wiring may not have been very perfect, and their creative solutions can really slow you down when you peek behind the wall, ready for your new install. Here’s what one of our members found, and how our community helped sort it out.

Original Post: Red Wire Used for Ground?

Harvey1847 Member

I have two questions. I want to put a light switch and light in a closet by running power from an electrical outlet box in the basement. Opening the box I found what I think is a 14-3 gauge Romex wire. The red wire is attached to the green ground screw, and the ground wire is loose. The black wire is attached to one side of the outlet and the white to the other side.

1. Is the red wire being used as a ground, and should I worry about this?

2. The outlet has a pair of screws on each side. One screw has the white neutral wire attached to it, and one of the two screws screw on the other side has the black hot wire. Can I run a 12-2 gauge Romex wire from the two extra screws on each side (black to black and white to white) to the new light switch and light that I want to install?

Thanks in advance for your help.

Highlights from the Thread:

ray2047 Group Moderator

“The red wire is attached to the green ground screw, and the ground wire is loose...” Is the red wire being used as a ground?

If is, it is a code violation and a safety issue. You need to find the other end of the cable and if the red is hooked to the ground on that end too it needs to be disconnected. To determine if the bare wire is a viable ground, measure voltage between it and the black. If it is less than 105 volts you probably don't have a good ground and this circuit cannot be used because by code an ungrounded cable can't be extended.

Harvey1847 Member

Thank you for your responses.

The Romex wire going into the outlet box has four wires. 1 black, 1 red, 1 white, and an uninsulated ground wire. This ground wire is loose. The "hot" black and the common white are screwed on to the outlet at the proper terminals. The red insulated wire is being used as a ground and is attached at the green grounding screw. Using an electric current tester I determined that the red is not hot. However, to be safe, and, as recommended by ray2047, I will follow it back.

Once I resolve the red wire question, can I use the second set of screws, mentioned in my initial post, to run a light to my closet?

Thanks again.

Justin Smith Member

You should be able to, but we won't know for sure until you trace the cable.

ray2047 Group Moderator

If the bare ground is good yes you can use it.

Read all the wiring and testing advice Harvey 1847 got at: //