Extending wire from conduit to reach into new bathroom ceiling fan

Question

I'm replacing on old bathroom ceiling fan/light, and the conduit comes to it from the left side, with only a short length of wires sticking out - but the hole into which the conduit wires should go is on the the other side of the fan box (which can't change as that's where the vent line is).

Here’s a picture showing the space and wires from the conduit. The hole meant for conduit would be on far right of screen - conduit wires won’t reach it, but what I meant before was that the fan’s attached wires stick out far enough that they could connect to the conduit externally.

The install manual/video says to run the conduit/wires into the fan box and then connect inside it, but since that doesn't seem possible as is, would I be better off to (a) just connect them outside of the box, with wire nuts, tape over, etc. (there's no insulation in that ceiling space, as it's between floors), or (b) get some extra pieces of wire and extend each of the wires coming out of the conduit (with wire nuts, tape over) to make them long enough to reach into the fan box, and then connect them to the fan wires inside the box as intended? Or, some other approach? Thanks!

Check the fan box over. Quite a few will have more than just one knock out hole to bring wires into it from different directions. — crip659, Jun 07 '22 at 18:41
Also look for slack in the run. That flex conduit may have a framing clamp that can be removed. — isherwood, Jun 07 '22 at 18:54
I'm curious about the wiring. Why are there four wires but none of them is green or bare? Did the old fan have three separate functions (eg, Fan, Light, Heater) ? I think that flex can be used as ground but only if it's a short tail, which would mean there is another actual junction box not far from this hole. I think if it goes all the way to the wall switch it's supposed to have a ground wire inside, which it apparently doesn't. Hopefully someone more knowledgeable can correct/comment on this. — jay613, Jun 07 '22 at 19:47
at the end all you want is to extend the wire to reach fan enclosure on the other side. So just extend the wires. Explained in detail in my answer. — Traveler, Jun 07 '22 at 21:32

score 3 · Answer 1 · answered Jun 07 '22 at 18:20

3

There are two primary strategies available. Which is best depends on the nuances of the situation.

Extend the conduit and pull new longer wires from the closest upstream junction box.
Add a junction box at the end of the conduit and extend with additional conduit and new wires from that box.

Note that any junction box must remain accessible, but this can include attic space with an access port.

answered Jun 07 '22 at 18:20

isherwood

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If the space is not accessible via an attic, the hidden junction box is exactly as accessible as the integral one in the new fan. The fan's box door can only be accessed by removing the fan, at which time the "hidden" additional junction box is there to behold. I'm no code expert, or even novice, but isn't that good enough? – jay613 Jun 07 '22 at 19:42
That's not true. Any fan I've worked with had interior access. – isherwood Jun 07 '22 at 19:46
Oh, now I have to climb up and look inside the one I just installed, from the outside, to see if there WAS access to the junction box from the inside. I don't remember seeing it .... but I wasn't looking for it. – jay613 Jun 07 '22 at 19:57

score 2 · Answer 2 · answered Jun 07 '22 at 18:59

What you have there is Flexible Metal Conduit, which terminates in a standard round knockout hole for 1/2" trade size pipe. (the hole being 7/8" diameter). In fact you can see a standard knockout on the side facing us in the photo. Now you see why it's called a "knockout".

You're saying "where is this knockout hole? I see an L-shaped metal plate."

The L-shaped plate is a "door", it is part of your old fan. It's provided as a convenience for assembly and replacement. Your new fan may have a door similar to it. I've seen installations where the door was identical (same manufacturer?) which worked out nicely for the installer lol.

If your new fan does not have that exact door, you will need to loosen the "conduit nut" from the old door. (it's not in view in the picture, but it's there.)

These things are meant to be turned by putting a flat screwdriver onto one of the "tangs" around the outside, and then bap the end of the screwdriver with the side of your pliers or a small mallet. However if you can get square-on to it with a pliers that should work too. They are not usually overly tight.

Extending wire from conduit to reach into new bathroom ceiling fan

2 Answers2