What do red wires mean in a 3-gang switch box?
Finding unexpected red wires instead of white makes it difficult to identify the switch leg versus the hot black wire. This confusion leaves people stuck trying to figure out if adding a new light is a reasonable DIY project or if they should hire an electrician.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Calling a licensed electrician
- 2Hiring a professional electrician to make the final connections
- 3Checking unlabelled cables for continuity before running new wire
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“Hi, I’m in Massachusetts and I’m trying to understand the wiring in this 3-gang switch box before deciding how much of the work I can do myself.”source ↗
“I’m mainly trying to understand the existing wiring and whether these additions are reasonable DIY work, or whether I should have an electrician make the final connections.”source ↗
“I’m still a bit confused about what I would need to do to add the new post light”source ↗
“When I opened up the box, I found red wiring instead of white. Is it possible to still use this switch? And if so, how?”source ↗
“In my other rooms, there were white wires which was why I had expected white. So one hot wire (black) and then the red would be the switch?”source ↗
Where this came up
People with this problem also raised
- 3How to plug multiple devices into a single wall outlet
- 3Why does my GFCI trip when wiring lights to it?
- 3Is it safe to cap and abandon a neutral wire for a standard switch?
- 4How to figure out what an unswitched wall light is connected to
- 3Not enough electrical outlets in the room
- 3Is this outlet backstabbed or backwired?