So I’m trying to replace a ~50 year old ceiling exhaust fan in my bathroom. It has an existing wall switch and I thought it was going to be an easy replacement. Not so much.
Besides being in a spot in the attic where I can just barely worm my way into, it’s not wired as I expected. In short, the line runs up into the attic suppling power directly to the to the fan housing in the ceiling, and then there’s another pair of wires running out of the fan housing and down to the wall switch.
The replacement fan I bought needs the line with power to run first to the switch and then continue up to the fan. I really like the fan I bought (the switch also includes a configurable humidity sensor), so I want to use it.
So I’m thinking I have to fish a new run from the attic down to the bathroom wall switch box to redirect the power to the switch, and then I can use the existing run from the previous switch to run power to the fan. Doing that new run is going to be a huge pain.
Wanted to check in with those who have more wiring experience than me - is there any better option I’m overlooking?
if the old fan is already switched you shouldnt have to do anything with new wiring. Is there any red wire? Black to black and white to white. The switch leg should break the black wire.
Nope. 2 conductors (black & white) and a bare ground.
“Easy” pictures coming up:
The old fan switch - hard to see in the back, but the wiring run comes into the box from the bottom in the back and has a black wire, white wire and a bare ground wire only. These run up to the attic and into a junction box on the fan:
You’re going to need a white neutral wire at the switch location, for that new switch. Right now, the black and white going to that box is just breaking the hot leg coming from the fan. Getting a neutral from a near outlet would be one option.
You might be able to “cheat”, and pick up the neutral from the ground wire, but that depends if your neutrals and grounds attach to the same buss bar in your main panel.
Thanks. I’m guessing running a single conductor wire won’t be to code, so if I’m fishing a run anyway I should just do a fully insulated 3 conductor + ground run?
A single conductor would be fine, if it’s in a shield. Otherwise, might be just as easy to run a normal 14-2 romex. Any chance there’s a standard outlet on the outside of that wall in the hallway, that you could pick up the neutral?
At least, in this case, you only have to snake back to the easiest, accessible box, not back to the fan.
Unfortunately not - the other side of that wall is the outside of the house. There is an outlet/light switch combo about 5 feet away on a perpendicular wall, but I’m afraid I’d have to break through wall tile to be able to maneuver wires between the two. Seems easier to come down through the top of the wall from the attic.
What I meant was he just can’t run a piece of low voltage bell wire that doesn’t have an outside jacket, like romex does. It has to have a second protective cover.
Except, if you read his OP, the fan is not in a easy place to crawl into and access it.
First, a correction. I should have said 14-3, not 12-3.
Not to be a jerk, but “shield” has a very specific meaning. Think braided metal jacket on a coax cable line like RG-6. I don’t know of any household wiring that meets this definition, save for maybe the service cable that feeds your panel/meter pan/subpanel.
I disagree strongly with the low-voltage bell line idea. From the pix, he’s missing a single 120v conductor in that box (side note, from the picture, the white should have been taped black to indicate it’s not being used as a neutral). Low-voltage bell wire is like 22 gauge or so and usually rated for 24v, which is way too thin to act as conductor for a 120v 15-amp circuit. Also, I don’t remember what the code says about doing something like this with multiple wires but I’d avoid it if at all possible.
Any chance you can use the old wire as a fish for the new? Might be stapled which would gum things up. Otherwise, it might be time to bring in a pro to get the wire where you need it. Please do it right! I could go on ad nauseam about the electrical house of horrors sh*t I have fixed in my lifetime.
