Wiring in a 2-gang box with switch and receptacle

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Old 09-14-06, 12:06 PM
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Wiring in a 2-gang box with switch and receptacle

I've got a 2-gang box in my garage that contains a receptacle on the left and a switch on the right. The switch controls a fluorescent light fixture in the garage, and the receptacle is independent of the switch (i.e., always hot). All the cable coming into the box is NM 12/2, and the circuit is 15 A.

I'd like to replace the existing receptacle with a GFCI receptacle. But there's a type of connection in the box that I've never seen before. I've got a poorly drawn diagram of it at http://www.jimkelly.be/wiring.jpg (which I'm sure doesn't follow convention, but hopefully it makes sense). Red = hot, black = neutral, and the gray arrows show the direction of current flow in the hot wires.

The confusing connection is on the top right (hot) terminal of the receptacle. The wire leading from the bottom terminal of the switch is continuous, but attached to the receptacle before continuing out to the light fixture. That is, it's not pigtailed to that terminal, but stripped midway along its length and attached.

My question is this: Can I cut that wire, attach the two resulting ends to a pigtail, and then attach that pigtail and the other hot wire (the one currently connected to the bottom terminal of the receptacle) into the two backwire holes on the "LINE" side of the GFCI (assuming I want the GFCI only to protect itself)?

Thanks!!!
 
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Old 09-14-06, 01:05 PM
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Where does the set of wires go that are drawn to the top right of the switch? If they are part of another circuit, then you have a serious problem that has a simple fix.

Also is the marked "LIGHT" always on?
 
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Old 09-14-06, 01:13 PM
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Everything in the diagram is on the same circuit. The set of wires coming in above the light switch come from some earlier point in the circuit I guess; that cable emerges from the wall that the garage shares with the spare room of the house, which is also on that circuit, so it probably comes out of one of the receptacles in there.

The light fixture is not always on; it's controlled by the switch in question.

Thanks again, and I apologize for any other inadequecies in the diagram!


Joe R.
 
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Old 09-14-06, 01:42 PM
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It looks as if one half of the receptacle is hot all the time and the top half is switch controlled. Is that correct? If that is the case you will have to correct that prior to installing a GFCI receptacle. If it all works, why not install a GFCI breaker?
 
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Old 09-14-06, 01:50 PM
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I'm sorry, I meant to point out originally that the entire receptacle is always hot (i.e., the tab isn't broken). My understanding is that the entire receptacle receives power via the wire on its bottom right terminal, and the wire on its top right terminal is just kind of "passing through" on its way from the switch to the light fixture. But I've never seen this arrangement before (but I'm no electrician, so maybe it's common, I don't know).

Yeah, GFCI breaker's a possibility, but I already have a few unused GFCI receptacles sitting around that I may as well use up.


Joe R.
 
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Old 09-14-06, 01:53 PM
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double check the feed. looks to me like the light would be the 2- wires on the right Above the sw.. 2- wire on the left bottom (rec) is the feed and on the top is the feed thru (gfci protected) to other rec.
Any case, the neutral should not be pig tailed like this.
Line (feed) and load neutral must be seperate.
The line neutral can share with the light.
Identify the feed wire. Assuming this is a GFCI rec.

On 2nd thought, Just re-read.. no GFCI now.
Is there one some where else on this ckt?
More than likely there is. check the basement or outside.
How old is your home?
 
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Old 09-14-06, 02:01 PM
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Nope, this would be the first GFCI on this circuit. The house was built in 1971, but from the looks of it, this box and the fluorescent light fixture in the drawing were added subsequently.

To clarify the drawing a bit, the cable feeding the light switch (top right) emerges from the wall the garage shares with the spare room. The cable feeding the receptacle (bottom left) leads to an exterior light fixture that I believe (but haven't confirmed) is the end of the run. As far as I can tell, the original configuration in 1971 was like this:

last receptacle in spare room -> cable through garage -> exterior light fixture

Sometime thereafter, the branch with the receptacle and the switch that controls the light fixture was inserted. I may be wrong, but that's how it looks to my untrained eye.


Joe R.
 
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Old 09-14-06, 02:38 PM
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What you are discribing doesnt quite jive with the wiring diagram.

double check that you have it all correct.
 
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Old 09-14-06, 03:03 PM
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jwhite,

Yep, you're correct. I've got it wrong. I've just gone over the whole arrangement in detail and I think I've got it figured out now. I'll put a new diagram up as soon as I finish drawing it.


Joe R.
 
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Old 09-14-06, 03:31 PM
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Okay, I've uploaded my revised drawing (which I did by hand this time, so I hope it's legible). I included the entire section of this circuit that's in the garage; as I assumed earlier, the circuit does enter the garage from the spare room.

In the drawing, the stuff that seems to be original to the house is the junction box, the exterior light fixture, and the garage door opener's receptacle (all the cables for those are clearly older, black insulated). The newer stuff is the 2-gang box in question (where I want to install the GFCI), the light switch above it, and the security light and fluorescent light fixtures (much newer looking cables, white insulated). Someone tapped off the junction box to add those extra lights and receptacle.

I hope this drawing makes sense to actual electricians! (And thanks for pointing out that my previous one was wrong.) I didn't include the other stuff (junction box, security light) in the previous drawing because I didn't think it was necessary, but clearly it was.

Anyhow, the original question was about what to do with that connection on the top right terminal of the receptacle. So you don't have scroll up: Can I cut that wire, connect the two ends together with a pigtail, and then insert that pigtail and the other hot wire serving that receptacle into the two backwire holes on the LINE side of the GFCI receptacle?


Thanks!
Joe R.
 
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Old 09-14-06, 03:44 PM
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It was commonplace years ago to make connections in the manner you are describing this one. It's not done this way now.

Yes, install a wirenut and pigtail the hot connections.

Make all your connections on the LINE terminals of the GFCI receptacle.
 
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Old 09-14-06, 03:52 PM
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FROM your drawing. The 2 conductor cable from the J-box is your feed.
If this is the case in the sw/rec box the "hots can be cut, spliced and pig tailed, as well as the neutrals.
This should leave you 1-black and 1-white (off the pigtails)for the GFCI, wich should be installed on the "LINE" side of the GFCI. Leaving the lights and door opener non GFCI protected.
Make sure all grounds (bare) are connected to the sw, GFCI and box (if metal).

I think thats all. If I missed something others will expand.
 
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Old 09-14-06, 04:16 PM
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Ah. Thanks everybody. I figured that might be a somewhat outdated (or just plain wrong) way of doing things, since I'd never seen it before. Good to know I can just pigtail all the hot wires.


Thanks!
Joe R.
 
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Old 09-14-06, 04:21 PM
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Make sure the power is OFF! When done plug something in and hit the test button.
 
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