I removed an old light fitting & there are 5 wires: Red, Black, Earth & 2 grey. My new fitting has space for 3

Question

I removed an old light fitting in my 1980's house porch. As far as I know there is 1 switch that operates one light. There are 5 wires. 1 Black, 1 Red, 1 Earth and 2 grey.
My new light fitting has space for 3 (live, neutral and earth?). What do I need to do with the spare 2 wires? Which wires are which? Does my house need rewiring?

Answer 1

I doubt your house needs re-wiring being only 20-something years old.

I prefer to run my power to my lights, by running power to the switch first, and from there, to the light, but not all folks do this. Some run the power to the light first, and then a couple of extra wires to the switch. (one to carry the power to the switch, one to bring it back)

Most single switch wiring is run with a black, and a white wire, with ground (usually bare copper)... and this is all in the same 'wrap' (like "Romex"), but this could be a case where someone just went out and bought 'X' number of feet of individually coated wire. Or, it could have originally been wired for two switches.

You NEED a volt-meter!
You can check which wires go where, by testing them with the power on. (Lol, of course, be careful not to touch the bare wires!!) I can normally test the wiring, safely, with all of them bare, but you may want to cap off all of them except the one you are going to test, and the ground. (This would keep you from touching one by accident)

Now with the volt-meter set to detect live voltage at up to 220v, you want to test each wire, by holding the meter lead wire to one of the coated wires, and the other against the ground wire. (Hopefully, you will only have 1 wire with power to it, but test EVERY wire! Do NOT stop testing when you find electricity in one...check them ALL)
If you have 1 wire with power (probably the black, or red wire) then that means that power was run to the fixture first....and those grey wires probably run to the switch. IF this is the case, then the next step, is to attach the 'hot' wire, to one of the grey wires. (Turn the circuit OFF before touching any bare wires! lol )
Now, with the 'hot' wire attached to one of the grey wires, and the switch turned ON, you should have power coming from the other grey wire, when you test it against the ground. (NOTE - check the wire, with the switch in BOTH positions....one will be on, one will be off... MOST light switches are set to flip 'up' to be ON, and 'down' to be off....if your switch is in the OFF position, and you have power across the grey wires, then that means you have the wrong grey wire attached to the 'hot' wire.)
Once you have the 'hot' wire attached to the correct grey wire (assuming those are for the switch), you can go ahead and wire nut, and tape those wires. (I like to use wire nuts, twisted onto the wires, and then electrical tape around the wire nut, to the wires themselves....I know the nut isnt going to fall off later, when pushing the wires back into the hole, hehehe)
Next you can run the other grey wire (which is now 'hot', when the light switch is on, and the circuit is on) to the white wire of your light fixture.
Attach the light fixture's black wire to the 'neutral' wire (If the black was the 'hot' then the red will be neutral, and if the red was 'hot', then the black should be neutral) and finish up by attaching the light fixture's ground wire to the house's ground wire.

So -- if that is what you find, then this is the way it will look when finished:
Black (or Red, whichever was 'hot') House to Grey House 1
Grey House 2 to Light fixture White
House Ground to Light fixture Ground
House Neutral to Light fixture Black

Now --- If you come up with more than 1 wire 'hot'...then youve got TWO power sources to the light. That could be because someone screwed up, lol... or there is a switch you havent found yet. You COULD just wire nut and tape it off.... but I have never liked the idea of leaving a 'hot' wire with no place to go.... It is better to go back to its source and unhook it. You can leave the wire in the wall...you just don't want any electricity running to it, if it's not being used.

Ok.... ONE other possibility here --- Youve got another light, or outlet, running off of the light fixture supply. If you do not see another light, or notice an outlet not working, then just cap off the unused wires.
If, when you were testing the wires.... and found that only 1 wire was 'hot' ONLY when the light switch was on.... then that means that power was run to the switch first, and the extra wires probably run to another light fixture box, or outlet (probably an outside outlet)

Ok, why would you have a red wire? -- well, it could be someone went out and bought individual strands, as I said earlier... and if that someone had worked on say, a car's wiring, they would have expected them to be black and red, not black and white. Or maybe they just liked red better than white, heheh. If both, the black and red wires have electricity, then it's actually a 220v circuit... and you probably do not need that on a light fixture (Im assuming you are in the U.S.) You NEED to find the source of that second hot wire, and disconnect it.

Remember:
Never touch, or hold, a bare wire....
Never go to twist wires together with the circuit on...
Always use a meter!

=) Be Safe!

Answer 2

I would not cut any wires off.The two that are not being used just cap off.you only need 3 wires the ground the neutral and the feed or switch leg which is the hot

Answer 3

the wires are suitable for a double-throw type of switch common on porches so you can turn it on coming in and off going out ( 2 switches)
BUT since they did not use 2 switches you simply can cut off and ignore the extra ones. look at the switch to see what ones are in use and cut off the extra ones.( turn power off first )