Switch w/ multiple lights

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  #1  
Old 03-11-03, 08:39 AM
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Switch w/ multiple lights

I've recently re-wired my home, and am hitting a snag I can't figure out. I had three old pull-chain light fixtures in my basement. I am re-wiring them so they all work off a switch. The power comes to the fixtures first, then ends at the switch. I understand that I need to bypass the fixtures by making the incoming hot black wire connect to the white, which is now marked black. I continue this hot wire, bypassing the next two fixtures, all connected to white wires, so it connects to the switch without hitting a fixture. The return is black, and now hits each light fixture. The switch works; however, when I do it this way, the lights are very dim. If I remove one light and make a connection (just to eliminate one light), the remaining two get brighter, but still not fully bright. By making it just one light in the series, it then has full power. I have a voltage tester, and it reads 110 volts at each fixture, so I am thinking the problem is with the amperage (as the brightness, which I am reading as wattage, is not as high as it should be when all three lights are in the series).

What am I doing wrong?

There are a few more mitigating circumstances to this. One of the lines in this run is an old BX wire - it was already run from light 1 to light 2, and I thought I could save some time. Is that somehow reducing the power?

Before the power comes to the first fixture, I have two outlets that precede it, and before that it is a direct line to the circuit breaker box. I've tested the two outlets, and they appear fine. Coould the source of the problem be there?

One last thing - I am still using the old light fixtures that were there. Could they be the source of the problem?

I've attached an illustration of what I am doing.
 
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  #2  
Old 03-11-03, 08:46 AM
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Switch w/ multiple lights

I am re-wiring three old pull-chain light fixtures so they all work off a switch. The power comes to the fixtures first, then ends at the switch. I've bypassed the first fixture by making the inital incoming hot black wire connect to the white. I continue this hot wire, bypassing the next two fixtures, all connected to white wires, so it connects to the switch without hitting a fixture. The return is black, and now hits each light fixture. The switch works; however, when I do it this way, the lights are very dim. If I remove one light and make a connection (just to eliminate one light), the remaining two get brighter, but still not fully bright. By making it just one light in the series, it then has full power. I have a voltage tester, and it reads 110 volts at each fixture, so I am thinking the problem is with the amperage (as the brightness, which I am reading as wattage, is not as high as it should be when all three lights are in the series).

What am I doing wrong?

I'm re-using some old BX cable that was already there, bewteen lights 2 and 3 - could that be an issue?

I'm also re-using the original light fixtures, which must be at least 20 years old - could that be a source of the problem?

I've attached a diagram of my wiring.
 
  #3  
Old 03-11-03, 08:51 AM
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Please ignore this 1st attempt to post - correct post is above.
 
  #4  
Old 03-11-03, 09:34 AM
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You have wired the lights in series. You need to change the cabling between the lights and the switch.
You need to run the switch cable to the first light. Or you need to run a x/3 between the light 1, 2 and 3 then regular x/2 to the switch.
Tell me which method you have and I will tell how to connect it.
 
  #5  
Old 03-11-03, 09:52 AM
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Not sure what x/3 and x/2 are - attached is the diagram of what I have done.

Would this have worked if there was only one light? If so, why can't I run more than one this way?
 
  #6  
Old 03-11-03, 10:01 AM
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The existing "feed-in" cable that has "constant" 120 volts across the Black & White wires at one of the fixture-boxes connects directly to the Black and White wires of a new 2-wire "feed-out" cable that goes directly to the switch-box. At the switch-box the new 2-wire "feed-out" cable from the existing fixture-box becomes the "feed-in" cable and the existing 2-wire cable between the switch-box and the fixture-box becomes the "feed-out" cable. At the switch-box the 2 Whites Wire-Nut together and the 2 Blacks connect to the single-pole switch.Operating the switch will connect the 120 volts across the Black & White wires of the "feed-in" cable to the Black & White wires of the "feed-out" cable to the fixtures.

At the fixture where the Black and White wires of the "feed-out" cable from the switch terminate, the Black and White cable wires connect to the Black & White fixture-leads and to the Black and White wires of the "feed-out" cables to other fixtures.At the fixtures all Blacks connect together and all Whites connect together----Good Luck!!!!!
 
  #7  
Old 03-11-03, 10:05 AM
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Originally posted by MarcReyn
Not sure what x/3 and x/2 are - attached is the diagram of what I have done.

Would this have worked if there was only one light? If so, why can't I run more than one this way?
x/3 x/2 is 14/3 or 12/3 depending on if you have 20 a or 15 circuit breaker. I can't see a diagram.
It would work with only one light. It won't work with 2 or more because you don't have a neutral for the return. You need to be able to connect each light to the black wore from the siwtch. If you coninue the black wire though to the other light then you don't have a neutral except at the last light where the power came in.
 
  #8  
Old 03-11-03, 11:10 AM
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Ok, I think I get it - then I can only have a switch with one line (source->fixture->switch) if I have it control only one light. If the switch controls more than one light, I need a "feed-in" and a "feed-out". In other words, I CAN'T do source->fixture->fixture->fixture->switch. It must be source->switch->fixture->fixture->fixture.

Is this correct?
 
  #9  
Old 03-11-03, 12:23 PM
jlbos83
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You can, but you have to use 3 conductor cable between the fixtures. To try to summarize....
You need an unbroken white from the source to each fixture. You need an unbroken hot (in this case black, and then white marked as black, would be fine) from the source to the switch (it can run past the fixtures, but is not hooked to them in any way). Then you run the switched power back to the fixtures, in the black from the switch, and then the reds between fixtures.
 
  #10  
Old 03-11-03, 12:46 PM
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Ahhhh, I got it now - the black brings the power to each fixture from the switch, and the red returns the power from each fixture back to the source white.

Thanks a bunch to everyone who replied!!
 
  #11  
Old 03-11-03, 01:04 PM
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Actually, you use the white not the red to return the power. Instead of coloring the white wire with black tape to feed the switch you just use the red wire.
 

Last edited by joed; 03-11-03 at 05:21 PM.
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