Three lights connected together, but separate switches?

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Old 07-03-16, 03:34 PM
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Three lights connected together, but separate switches?

Good evening. We're tackling a downstairs bathroom project (new ceiling, light, fan, paint, etc...) during our long holiday weekend. I've replaced numerous fixtures around the house, but haven't run into anything like this. I imagine it is fialry common, just something I haven't seen. I'm hoping someone can give me a heads up on this wiring. There are three ceiling fixtures (each with a single switch) and one wall outlet on the circuit. So each switch powers one and only one ceiling fixture, each fixture is controlled by only one switch, and the wall outlet is always hot. I tore out the existing ceiling in the bathroom, so I have the wiring exposed to the old fixtures. Here is where I am confused. Each fixture has the romex with ground going to it's switch. The fixtures are also connected to each other (I haven't tested each wire, so I'm going based only on color now):

Vanity fixture-
1) Romex from switch to fixture.
2) Romex from fixture out to ventilation fan fixture.
The two hot wires are connected just to each other. One neutral is connected to the fixture hot; and one neutral is connected to the fixture netural. Grounds are connected to each other.

Venitlation fan-
1) Romex from switch to fan.
2) Romex in from vanity fixture.
3) Romex out to light fixture in adjacent hall.
The three hot wires are connected just to each other. The three ground wires are connected to each other. The neutral wire from the light switch is connected to the fan's hot wire. The other two neutral wires are connected to the fan's neutral.

Adjacent hall fixture-
I haven't checked it since it is in a different room with the ceiling intact. My gut tells me if I take it down it will be wired similar to the vanity light... with Romex to the light switch and the Romex in from the ventilation fan.

I guess I'm confused as to why the fixtures are connected to each other since they each have a dedicated switch. I've seen it where a line of lights is connected by a single switch, so power has to go from one to the next and so on. Why would these be connected to each other? When I hang the new fixtures should I wire it the same way? That is a ton if wiring to squeeze into the ventilation fan since it is already a dual fan/light that I'll be running off the single switch.

Thanks in advance for any input. And have a great holiday weekend!
 
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Old 07-03-16, 05:02 PM
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There are two basic ways to wire a switch/light combination. In one case, the power source comes into the light fixture box. In the other case, the power source comes into the switch box. You have the power source coming into the light fixture box. The romex from there to the switch is commonly called a switch loop.

I've attached diagrams of each setup below to help you understand how it works. Your situation is a little more complicated in that you have 3 combinations involved, which means you have additional romex cables to carry the power source from the first fixture box to the second, and from there to the third.

On a switch loop, the white wire is not a neutral, but a switched hot wire. It is supposed to be marked with black or red tape or paint to make it clear it is not serving as a neutral.

Review the diagrams and if you have more questions, fire away!

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Old 07-03-16, 05:38 PM
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That is a ton if wiring to squeeze into the ventilation fan since it is already a dual fan/light that I'll be running off the single switch.
You are correct, you don't want your source power coming into the fan. The source should be moved to the switch box, and new three conductor cable ran from switch box to fan/light combo.

This method not only gets rid of all the wires that would be in the fan, it also allows you to switch the fan and the light separately.
 
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Old 07-03-16, 05:39 PM
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Thanks for the fast reply! I'd seen that term in my searching, but wasn't sure if that was what I was seeing. So I should be good wiring the new fixtures in the same was as the old ones then. I'd already taped the switched hot at the vanity fixture so I wouldn't lose track of it. I haven't messed with the old fan yet. Do you see a problem with adding a junction box next to the exhaust fan? I'm just trying to figure the best way to enclose all the wiring at that one fixture. I'm thinking connect the three black hot wires together in the junction box. I'd pigtail from the two true neutral wires in that box out to the neutral in the fixture box. I'd pigtail from the switched hot wire out to the hot wire in the fixture box. And then I guess connect the grounds together in the junction box and pigtail out to the fixture? Thanks again for the quick reply.
 
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Old 07-03-16, 06:52 PM
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The switch loop shown is no longer code compliant when using cable. When using cable you must have a neutral at the switch box even if not needed so you need to use a 3-conductor cable not a 2-conductor cable. Any new lights must meet current code.

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Old 07-04-16, 09:12 AM
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What do you wish to perform or accomplish?

Historically you had:

Step 1. Power goes to one light fixture and daisy chains from or tees off from there to the next light fixture and so on. If that was all then all the lights would be on all of the time. Easy and straightforward.

Step 2. At each light fixture wiring was run down to a switch to make a switch loop. This results in each switch controlling one light independently of the other switches.

Treat it all as power going to the light first and then to the switch for each light.

You can replace any of the fixtures by connecting the new fixture to the same wires (black and white) that the previous fixture was connected to.
 
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