I have red blue black white and copper(ground) coming out of my bathroom ceiling. I'm hooking up a fan light combo with 2 black 2 white and two green wires. I need to know which wires go to which?

  • 2
    You need to specify what part of the world you're in. Colors are used to mean different things in different places. – Tim B Feb 5 '17 at 20:07
  • How are they grouped? To which I mean, the wires arrive either in one or more sheaths (wrappers) or a conduit hole. Which wires are in which sheaths/holes? If they're all in one sheath, you have the almost mythical 14/4 or 12/4 cable. Cool. – Harper - Reinstate Monica Feb 5 '17 at 20:28
  • So is this an exhaust fan and light combo? How many switches are there on the wall 2 or 3? Did the original unit that you are replacing have three devices in it: (1) a regular light, (2) an exhaust fan and (3) a heat lamp w/ or w/o a fan blowing over it? Leaving aside the ground wire you have 4 wires coming out of the ceiling, one question is are two hot and two neutral or are three hot and one neutral. – Jim Stewart Feb 5 '17 at 22:29
  • Can you post photos of the inside of the light/fan box and the switch box that controls it please? – ThreePhaseEel Feb 5 '17 at 23:10
  • Does your instruction manual provide a wiring diagram? Typically, you can find the wiring instructions by looking for the model online. If you post a diagram, we can help interpret it. – Hari Ganti Feb 6 '17 at 21:15

A bathroom overhead light position commonly has 3 separate loads in it:

  • Overhead light
  • Fan
  • Heat lamp or air blast heater

A perfect cable

enter image description here source

The electrician who installed this did an excellent job future-proofing, going out of his way to use the rarely-seen 12/4 or 14/4 cable. This is perfect for a bathroom overhead light, because it provides all the wires you'll ever need, in one cable: black, red and blue are "hot" wires for all 3 of the above loads. White is a shared neutral, and ground is ground of course.

You can choose colors as you please, or as the bathroom switches are already wired. You can tighten the wire-nut not-so-tight to hold wires together for testing, or pop the cover off the bathroom switch and see how that's wired.

One of your wires will not be used; if it's not already capped, just put a wire-nut on top of it and tape the wire-nut onto the wire so it doesn't fall off (as they're prone to with only one wire).

All the neutrals get tied together.

Why does the fixture give two white wires?

They are both neutral. One is the neutral for the lamp, and the other is the neutral for the fan. This gives you the flexibility to feed the lamp and fan from separate circuits (in that case the neutrals would need to be separated.)

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I'd use a voltage tester to find out if any of the black, blue & red in the ceiling is permanently hot or is turned off by a switch somewhere nearby.

Then I'd wire the appropriate wires depending on which switch I wanted to control the fan and which the light

enter image description here

Some (many? most?) fan and light combos have a pull-switch on the unit or a wireless remote control, I suspect that might not be the case here as you have two complete sets of wires. If it is the case and you want that switch/remote to solely control whatever it controls, you need to connect the relevant black to a permanent hot wire (which would also be black in a rational world but I'd check with a voltage tester).

Using the type of connector pictured below makes it easier to try out connections to see which black is fan and which light (or some other funky combo - see instructions for fan/light unit). Otherwise you might be having to make and remake connections with wire nuts - which I suspect is annoying.

enter image description here

I don't live in a part of the world that uses those wiring colours or which has much use for ceiling fans, so take my advice with a pinch of salt.

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