Confusing switch wiring

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Old 11-11-12, 02:05 PM
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Confusing switch wiring

I am trying to replace 2 single-pole switches that are in the same receptacle in my garage. One switch controls 2 indoor garage lights and I'd like to replace it with a motion sensor switch, and the other controls my 3 outdoor garage lights, and I'd like to replace it with a timer switch. They are all on the same 15A circuit, along with some kitchen lights. I'm a little confused by what I see when I look at how the switches are wired. Here is a description:
  • 4 cables are coming into the receptacle; 3 are 14/2, and one is 14/3.
  • All white wires are joined together in a single wire connector.
  • The black wires from the three 14/2 cables are joined together and feed the bottom terminals of each switch. Two of the black wires are labeled "feed" and one is labeled "HR."
  • The red wire of the 14/3 cable is labeled "inside lights" and is wired to the top terminal of the switch that controls the inside garage lights.
  • The black wire of the 14/3 cable is labeled "outside lights" and is wired to the top terminal of the switch that controls the lights outside the garage.
Am I correct that black wires are the "hot" side and the 14/3 red and black wires represent what would typically be the "load" side of the inside and outside lights resp.?

I guess what I find confusing is that if I am correct, it looks like that single 14/3 cable coming out the box must somehow then get split somewhere to the different lights, rather than having each light circuit come into the box with its own cable. Is this typical?
--Rob
 
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Old 11-11-12, 02:15 PM
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Welcome to the forums, Rob!

Am I correct that black wires are the "hot" side and the 14/3 red and black wires represent what would typically be the "load" side of the inside and outside lights resp.?
Yes, that's correct.

I guess what I find confusing is that if I am correct, it looks like that single 14/3 cable coming out the box must somehow then get split somewhere to the different lights, rather than having each light circuit come into the box with its own cable. Is this typical?
No, but it's not unusual either. It's completely in compliance with code. You can just replace the switches.

One word of caution on the motion sensor, though. It will only keep the lights on during the time if can see motion, plus whatever delay you set on it. So you need to make sure it is where it has a clear view of the garage, and then set a long-enough delay on it to cover yourself.
 
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Old 11-11-12, 02:36 PM
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Thanks

Thanks for the welcome and speedy reply. Not having done much house wiring before, aside from the occasional intallation of recessed lights and changing switches, I had a hard time envisioning why the electricians who wired the house would have done it this way.

It looks like the motion sensor switch doesn't require a neutral but the timer switch does for some reason, so I will connect its white wire to the common white connector.

An additional question: the black feed to one switch is actually "jumped" from the ower terminal of one switch to the lower terminal of the other switch (ie, they removed a short stretch of insulation and wound that stretch of wire around the terminal nut, then continued to the other terminal). Is this done to avoid connecting another short stretch of wire to the common black wire nut? Is it to save time? Should I just replicate it, using the same wire? Is it to code?
-Rob
 
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Old 11-11-12, 03:09 PM
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Not having done much house wiring before, aside from the occasional intallation of recessed lights and changing switches, I had a hard time envisioning why the electricians who wired the house would have done it this way.
It saved them a second run of 2-conductor cable and one neutral in the neutral splice. Plus it may have made a neater-looking installation.

the black feed to one switch is actually "jumped" from the ower terminal of one switch to the lower terminal of the other switch (ie, they removed a short stretch of insulation and wound that stretch of wire around the terminal nut, then continued to the other terminal). Is this done to avoid connecting another short stretch of wire to the common black wire nut? Is it to save time? Should I just replicate it, using the same wire? Is it to code?
Yes. Some installers like to do that to save adding another pigtail into the splice or to save a little room in the box. I never thought it was worth it unless I had three or more switches to power up, but others do.

That jumper complies with the code requirements so long as the insulation ends right next to the screw terminal in every case. You can use it for your two new switches so long as it reaches the needed terminals without stretching and the insulation stays where it needs to be.
 
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Old 11-11-12, 03:19 PM
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OK, thanks. I'll have to think a bit more about your comment re saving them a 2nd run of two-conductor cable. Still having a hard time picturing all the connections, but I appreciate your feedback and now feel more comfortable replacing the switches.
 
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Old 11-11-12, 03:26 PM
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Still having a hard time picturing all the connections,
Maybe this will help: Somewhere down the line, probably at the first inside light, a 2-conductor cable branches off to feed the second set of lights. It is connected to one of the hot wires and the shared neutral. The first set of lights is connected to the other hot wire and the shared neutral. Both light strings are then extended with 2-conductor cable.
 
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Old 11-11-12, 06:07 PM
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Trying to see if I'm following you...
Perhaps easier to simplify and assume one indoor light and one outdoor light. So is this what you're saying:
  • 2-conductor power supply cable coming into switch box with black feeding both switches.
  • 3-conductor cable connections in switch box: red wire to inside light switch, black to outside light switch, white to other white wires.
  • 3-conductor cable comes out of switch box and goes to a junction box at/near inside light.
  • In junction box near inside light:
    [*=1]red wire from 3-cond cable connected to black wire of inside light
    [*=1]black wire from 3-cond cable to black of a 2-conductor cable going to outside light
    [*=1]white of that 2-cond cable to white's inside jcn box, and then at other end, to white at outside light
If that's correct, I see how you now have fewer cables going into the switch box. But then I can't figure out what the other two 14/2 cables are doing in the switch box. They each have black wire connected to the blacks and white wire connected to the whites. What would they be connected to? Could they be going to the kitchen lights that are on that circuit?
 
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Old 11-11-12, 07:35 PM
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In junction box near inside light:
  • red wire from 3-cond cable connected to black wire of inside light
  • black wire from 3-cond cable to black of a 2-conductor cable going to outside light
  • white of that 2-cond cable to white's inside jcn box, and then at other end, to white at outside light
We may be saying the same thing in different ways, but I would say
In junction box near inside light:
  • red wire from 3-cond cable connected to black wire of inside light
  • black wire from 3-cond cable to black of a 2-conductor cable going to outside light
  • white wire from 3-cond cable to white wire of inside light, and to white of a 2-conductor cable going to outside light

I can't figure out what the other two 14/2 cables are doing in the switch box. They each have black wire connected to the blacks and white wire connected to the whites. What would they be connected to? Could they be going to the kitchen lights that are on that circuit?
Are there three 14-2/G cables entering the switch box? OK, then, as you surmise, one is power in and two are power out. They could be feeding the kitchen lights or receptacles in the garage or the garage door opener or outside receptacles or... who knows. You would have to map your circuitry AND trace wire runs with continuity tests and/or tone generation equipment to find out for sure. But yes, one in and two out.
 
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Old 11-11-12, 08:37 PM
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Yes, I agree with your edit of my description--that's a better description of what I was imagining (which I had to draw on a piece of paper).
Thanks so much for helping me along with this--the setup makes much more sense to me now. I hadn't realized that there might be two power cables coming out of that box that were not exactly related to the lights controlled by the two switches, but instead could be feeding other lights in the circuit (likely kitchen lights since they went out when I shut the breaker). This was a good learning experience for me.

One final small question: two of the black wires from the 14/2 cable are labeled "feed" and the black wire from the third 14/2 is labeled "HR." Not sure if this is standard shorthand, but any idea what HR might stand for?
-Rob
 
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Old 11-11-12, 08:52 PM
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any idea what HR might stand for?
Home Run. That's the cable from the panel. The two marked "feed" are the hot wires for the other loads fed out of this box.
 
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