Switch loop with two fixtures


  #1  
Old 12-29-03, 09:39 AM
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Question Switch loop with two fixtures

Long time, no 'see' y'all. I hope everyone had a wonderful Christmas. Happy New Year!

I searched the forums (thankfully using the OLD search that is much better than this new [to me] search) to see if my question had already been answered. It was *almost* answered in a thread started by snovosel back in April.

Short version: I want to wire a switch loop with two fixtures.

Long version w/explanation: I have an existing non-switched light fixture. I want to switch it and add a new fixture to the same switch. An existing junction box is immediately next to the existing fixture. The run I have to make is somewhat long, so instead of having to double-back I was planning to run a switch loop. I completely understand a switch loop with a single fixture. I wasn't so sure of multiple fixtures. Since I couldn't find any info specifically regarding a switch loop with multiple fixtures, I came up with the following:

Legend:
* JB=junction box from which to 'tap' into circuit for continuous power
* L1=first light (next to JB)
* L2=second light
* SW=switch

At L1 connect:
- WHITE from JB to WHITE from L1
- BLACK from JB to WHITE running between L1 & L2
- BLACK from L1 to BLACK running between L1 & L2

At L2 connect:
- WHITE running between L1 & L2 to BLACK from SW
- BLACK from L1 to WHITE from L2
- BLACK from L2 to WHITE from SW

At SW connect:
- WHITE from L2 to SW
- BLACK from L2 to SW

Here is a link to a crude Word drawing of what I just described:

www.geocities.com/rcmoonpie47/
- click on Switch Loop with Two Fixtures

All seemed fine and dandy until someone pointed out that the lights would be in series (since, I assume, you can't pigtail on a switch loop) and if one light blew the other wouldn't work. I was thinking (WATCH OUT!) that there was continuity in the metal parts of a bulb and that as long a bulb was in the socket--even if the filament blew--the circuit would not be broken and the other light would burn (as long as the switch was on of course!).

So here are my three questions:
1) Can you safely & legally wire a switch loop with two fixtures?
2) If so, is the way I described OK?
3) If so, will one light continue burning if the other light blows?

Thanks so much!
 
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Old 12-29-03, 10:04 AM
P
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All you need is a 3-wire cable from the existing fixture to the new switch outlet-box, and a 2-wire cable from the switch outlet-box to the new, additional fixture outlet.

This suggestion presumes you have a "feed" cable at the existing fixture, and that the new fixture is closer to the switch than it is to the existing fixture.

Good Luck & Enjoy the Experience!!!!
 
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Old 12-29-03, 10:45 AM
R
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There are several ways you can go, and the best way is whatever is easier for you, based on the layout of the house, and where you want the new ficture and the switch.

First, the junstion box you mention is superflous information. If you have constant power to the light fixture then you do not need to find s source of power.

Basically, what you need to do is to add a switch loop to control the existing ficture. Then you simply connect the new fixture in parallel with the existing ficture.

As Pas suggested, you can run 14-3 from the existing fixture to the switch and then 14-2 to the new fixture, or you can run 14-2 from the existing fixture to the switch and 14-2 from the existing fixture to the new fixture.

Make a determination which will be easier to wire and then let us know. We can help you with the exact wiring from there.
 
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Old 12-29-03, 12:38 PM
J
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As Bob says, you have lots of choices. I generally don't recommend switch loops for the DIYer, simply because they can lead to a variety of mistakes, one of which is the mistake you made.

Here are a few options (where "-" is 14/2 and "=" is 14/3):[list=1][*]JB-L1=L2-SW[*]JB-SW-L1-L2[*]JB-L1-SW, and L1-L2[*]JB-L1=SW-L2[/list=1]Take your pick. Note that JB-L1-L2-SW (what you drew) is not on the list.
 
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Old 12-30-03, 07:16 AM
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Thanks all 3 of y'all for responding.

Due to the physical locations of the existing JB & light, and where the new switch and light will go, either #1 or #4 of John's options would be the most feasible (the new switch and new light will be in close proximity to each other).

If I wouldn't have to 'double-back' so far, I would have chosen #2 to begin with which I have no problem with. But it's a pretty long run and I'd prefer to conserve the cable.

So, if y'all don't mind, could you detail the connections of either #1 or #4? I played around with my 'schematic' for a while and couldn't figure out what exactly to do.

Thanks!
 
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Old 12-30-03, 07:31 AM
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For #1:

At L1:
  • 14/2 black to 14/3 black.
  • 14/3 red to L1 black
  • 14/2 white to 14/3 white to L1 white.
  • Both grounds together, pigtailed to L1 ground.
At L2:
  • 14/3 black to 14/2 white (remarked black).
  • 14/3 white to L1 white.
  • 14/2 black to L1 black to 14/3 red.
  • Both grounds together, pigtailed to L1 ground.
At SW:
  • Ground to green screw.
  • Black and white to other two screws. Remark the white.
Or for #4:

At L1:
  • 14/2 black to 14/3 black.
  • 14/3 red to L1 black
  • 14/2 white to 14/3 white to L1 white.
  • Both grounds together, pigtailed to L1 ground.
At SW:
  • Ground to green screw.
  • 14/3 black to one of the other screws.
  • 14/2 black to 14/3 red, pigtailed to the remaining screw.
  • 14/3 white to 14/2 white.
At L2:
  • 14/2 black to L2 black.
  • 14/2 white to L2 white.
  • 14/2 ground to L2 ground.
 
  #7  
Old 12-30-03, 08:48 AM
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John:

Thank you so much!

I added to my Word drawing that I linked to above in case anyone wants to look at it. After 'drawing' the connections you described, I had an 'Eureka!' moment and easily saw it then.

I don't know why I couldn't logically figure it out when I was earlier pondering how to use the 14/3. I see now how the lights will no longer be in series this way, yet both included in the switch loop.

Thanks again!
 
 

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