Grounding for Single Switch?

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  #1  
Old 03-27-06, 08:14 PM
stuemke
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Grounding for Single Switch?

We just painted a small bedroom in our house (20 years old) and decided to update all the switches and outlets. First thing I did was killed the power to that room, so all the outlets and switches are dead.

As I took out one of the switches (single-pole) for a closet, I saw that there was no grounding wire attached. Instead there was two black wires connected in the push-pin areas on the back. (I'll be screwing them on the sides instead of in the back.) The ground wire wasn't attached, though.

Instead, the three (I'm assuming) copper ground wires are wound together and they were shoved in the back of the box behind the other coated black wires. So here are my questions:

1) Is this legal? I know nothing of electrical codes... just to put it back as I saw it.
2) Do I need to run some type of coated copper wire from the spun copper wires in the back to the green ground screw on the switch?

Thanks in advance for the help!

-stuemke
 
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  #2  
Old 03-27-06, 08:30 PM
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Since you are removing the switches, purchase newer switches with grounding lugs on them, attach the bare wire to the green grounding lug and install it in the box. I have seen this many times, and cannot figure why anyone would go to all the trouble to run the wires, twist them together, and then fail to put them on the switch. The reason I suggest purchasing new switches, is for wear factor. Years of use can take its toll on them, and since you have them out now, why not go ahead and change them?
 
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Old 03-27-06, 09:03 PM
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If the switch is in a properly grounded metal box, you do not have to attach a separate ground wire to the switch.
 
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Old 03-28-06, 04:19 AM
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The ones I see aren't. The grounding wire is just twisted and pushed back in the box, metal or plastic. On the metal boxes, they don't even use a grounding screw. Just for info.
 
  #5  
Old 03-28-06, 04:41 AM
stuemke
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I think the scenario chandler is describing is right on the money. The three wires are spun together and then just shoved into the back of the recepticle box... and they're not attached anywhere to the box.

We did purchase new switches and outlets in 10-packs from a local store, but none came with a green wire to connect from the ground screw on the switch to the spun wires in the box. (These are the 10-packs of barebones switches and outlets. We're buying the recepticle covers separately.) Can you tell me what type of wire I need to get to put there? Is it 12 gauge or 14 gauge or something else? Does it need to be pure copper?

Thanks for the help. With any luck, we'll get the power back on in that bedroom tonight!

-stuemke
 
  #6  
Old 03-28-06, 06:45 AM
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You can use 14 gage wire for the ground. It needs to be either bare copper or with green insulation. Figure 8 or 10 inches per box and get that amount of #14 THHN green solid wire. If you are going to ground the metal boxes also, add 6" per box. You might want to get some extra large wire nuts (often gray in color) because you will be putting more wires under the wire nut. For plastic boxes, you need to run a ground wire to every switch (and of course outlet).
 
  #7  
Old 03-28-06, 06:47 AM
assemblage
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I'm not an electrician, but have done some rewiring of my 50's ranch.

Chances are that your lights are 14/2 NM cable. You want to match your wire with the size of wire that's there, which should be matched with the circuit. 14 AWG (guage) cable is for 15 amp circuits and 12 AWG is for 20A circuits. Many wire strippers have a wire gauge on them... also if you try to strip a 14AWG with a 12AWG stripper, it won't work. Also, you may want to get a Klein brand stripper. I got a $20 stripper that does 12/2, 14/2, 12 and 14 AWG wires and it works so much better than the $7 multipurpose cheapo.

Once you figured out what size is there, you can buy the wire. They sell bare copper wire for ground. I use scraps of my NM cable and pull the bare copper ground wire out of the scrap. You might be able to dumpster dive and new home construction sites to get scrap. That would be fun and save money. Since the pieces you need for the pigtail probably wouldn't be more than 4" (although I believe according to code you need 6" of wire from where it enters the box to tip, so be careful snipping the old wire), you could get coated wire and strip the insulation off. That would be a bit of a pain though. While it may be ok to use purple insulated wire for the ground, I think most people will recognize a bare copper wire as the ground. The wire has to be copper.

Since you say the wires are just twisted together in back, it reminds me of how my wires were done. Twisted together and covered in electrical tape, which is now brittle and falls off. Wire nuts work much better and they are required by code. So for the ground, you screw the wires with the short piece of bare wire(pigtail), curl the end of the pigtail, and screw it on the ground. Wire nuts are sized for the guage of wire and how many of that guage you are screwing together (it's on the package).

Also metal boxes must be grounded with grounding screws. Those are the overpriced green ones in the elctrical section. I don't know about the grounding of switches and recepticles in metal boxes. I cut mine out because they were undersized and replaced them with deeper plastic "old work" boxes.

I may be missing something, but the screwing the wires on the side of the switches is more difficult than pushing them in the holes in the back. To push in the back, you just use the strip guide on the switch/recepticle, strip and push in. No curling or screwing. Why would you opt for screwing on the sides?
 
  #8  
Old 03-28-06, 07:06 AM
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The NEC is explicit that wire used for grounding can only be bare copper or green insulated and no other color.

The reason that it is better to screw the wire to the screw rather than push it in the back is because the back connection relies on the spring tension of metal, which can fatigue. I have pulled a lot of "back stabbed" outlets and switches and the wires usually twist out quite easily. Look at all of the posts to this forum about a circuit that all of a sudden doesn't work, but the breaker is not tripped. The usual cause is a loose wire. I guess that maybe half of those incidents are caused by back stabbed wires, and the rest by loose wires under a wire nut. I have also pulled devices with a problem, to find that the wire was poorly attached to the screw. The wire should go clockwise around the screw (tightening the screw pulls the wire in rather than squeeze it out) for at least 2/3 of the way. An exception is many GFCI outlets and some specialty switches that use a grip the wire when it is back stabbed. Tightening the screw squeezes the wire in a clamp.
BTW, newer outlets and switches will only allow 14 gage wire to be back stabbed, not 12 gage.

All outlets must have a ground wire. Switches do not need a ground wire to the switch if they are in a properly grounded metal box.
 
  #9  
Old 03-28-06, 07:32 AM
assemblage
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Thanks that's good info about connecting the wires.
 
  #10  
Old 03-30-06, 06:02 PM
stuemke
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Problem Solved!!!!!

Here's a quick recap: we painted a small bedroom, replaced all the outlets and switches with new and uniform outlets and switches. I hooked up the electrical when the painting was done, and I had no power coming through to the room.

A few days later and a LOT of frustration later and I finally saw the problem.

Inside one of the wall switches, there were three wires piggy-tailed together with a wire screw. While removing the old switch and installing the new one, one of the wires inside the wire screw snapped off, but the wire housing (ie. insulation) stayed hidden inside the wire screw. Because it looked the same as the rest, I assumed it was okay.

Only tonight, when I took off all the wire screws in every outlet and every switch, did I notice that the numbers didn't add up. I did some deeper checking and that's when I found the break in the wire. It turns out that the one that broke was the hot wire coming from the parallel box in the living room. That's why everything in the living room still worked but the bedroom went dead.

Frustrating... but FIXED!

Thanks, everyone, for your help.

-stuemke
 
  #11  
Old 03-30-06, 06:18 PM
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a case for heavier copper

> one of the wires inside the wire nut snapped off

#14 copper or #12 copper-clad aluminum?


With #14 you need to watch if you make and unmake the connection a few times, the wirenut cuts grooves in the wire and weakens it.

Copper can only take so much bending until it breaks.
 
  #12  
Old 03-30-06, 06:55 PM
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stuemke,

I'm glad you found your problem. Thanks for posting back with the problem.

I combined your posts, as we don't need a new thread for your results, they can stay in the original thread.
 
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