Help! Yet another open ground mystery.

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  #1  
Old 01-24-13, 07:45 AM
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Help! Yet another open ground mystery.

I'm hoping you guys can help me out because I'm at a loss and I really can't afford an electrician. Hell, even my brother in law who is an apprentice electrician can't figure this out (or he doesn't want to).

My house was built in 1979 and the electrical is up to date, at least according to my inspection back in 2008. In my living room I have 6 duplex receptacles. 1 is on a separate breaker, but receptacles 2, 3, 4, 5, and 6 (I'll call this the end of the run since the box only has one romex run going into it) are all on the same breaker. None of these are GFIs and my breaker box only has one GFI breaker, and that's for the bathroom or kitchen (sorry, can't remember off the top of my head and I don't have my chart handy).

A few weeks ago I plug in my vacuum into #6, turn on the vacuum and the vacuum is running for a bit and then it shuts off. This happens on occasion and it's only ever the breaker that gets tripped. I go down to the basement to the breaker box, and no breakers are tripped. I go back upstairs, try to start the vacuum again, and nothing happens. I try receptacles 6, 5, 4, 3, and 2 to no avail. I try receptacle 1, and the vacuum works fine. Back to the breaker box then and I throw each breaker individually. Go back upstairs, still no activity from 6, 5, 4, 3, or 2. The vacuum won't work and even a little table lamp wouldn't work. I get my 3 prong tester and they're all showing Open Ground.

I figure it's a good time to replace all of the receptacles with childproof ones and so I buy a pack of childproof duplex receptacles. I turn the breaker off so I don't electrocute myself. As I'm replacing receptacles 2 through 6, I notice that whoever put the old ones in used the backstab holes, but none of them were loose and there were no charred wires, so no evidence of arcing. For the new receptacles, I've wired them to the screws on the side. I flip the breaker back on and still no dice. I also noticed that the ground wires for 2 through 5 were clamped together with a metal clip (plastic boxes were used so there is no ground wire screw in the box). I clipped the ground wires and used a ground wire nut instead. Flip the breaker back on and 2 and 3 now show that they're wired correctly, but 4 through 6 still show Open Ground.

I re-check all of the wiring and everything is solid. I even tighten everything for good measure. Same result, 4 through 6 are still Open Ground and you still can't even use anything as small as a table lamp with those outlets.

Time for the multimeter. For 2 and 3, the receptacles that now work, neutral/ground show 0 while hot/ground and neutral/hot show 124. 4 through 6 show 0 for neutral/ground, but only 40 for hot/ground and neutral/hot.

There are no switches connected to these receptacles and there's only 2 switches to begin with in this room that are on a separate breaker for the outside lights. Does anyone have any ideas? Do receptacles 2 through 5, the ones with 2 romex lines with 3 wires each, all need to have the 2 neutral and 2 hot wires terminated on the same screw for each receptacle? That's one place where I may have flipped the top and bottom positions of the neutral or hot wires, but in everything I've read, it shouldn't matter so long as you have the neutral and hot on the correct sides of the receptacle.

There's another electrical oddity with my house two, involving my three bathrooms. We have a bathroom on our lower level, an upstairs hallway bathroom, and a bathroom in our upstairs bedroom. Whenever my wife uses her blow dryer in the upstairs hallway bathroom, the GFIs in all the bathrooms trip, and they're frozen for a day, or two days, or three days, or an hour, etc. It's really random. And this is regardless of us switching the breaker off and back on. I've switched out each GFI in the bathrooms, they're all wired correctly, but that issue keeps happening. I believe the same thing happens if you use the blow dryer in any of the bathrooms. Anyway, just wanted to throw that one out there as well.
 
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  #2  
Old 01-24-13, 08:36 AM
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Welcome to the forums!

If the receptacles are wired in the order you believe they are, re-check the connections at #3. Use pigtails to connect the hots together and to the receptacle, and do the same for the neutrals.

See Troubleshooting a dead receptacle or light, Basic Terminology & Other info

Ground is an emergency conductor. It is nor needed for the receptacle to work. Sounds like a poor hot connection.
 
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Old 01-24-13, 10:07 AM
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The open ground will not affect the ability to power a table lamp or any other load. It is only used in the event of a fault.

Try the troubleshooting sticky in the reply above and let us know what you find. I too suspect your problem is at #2 or #3.

Only one wire per screw head.
 
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Old 01-24-13, 11:46 AM
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Just to clear up any potential confusion, but I do only have one wire per screw.

To make sure, when I do this troubleshooting, should I start with #2 with pigtailing the neutral and hot wires, check to see if the issue has been fixed, and if it's not, should I then undo the pigtailing to then try the same at #3?

Also, if the issue is potentially at 2 or 3, how come those receptacles work without issue?
 
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Old 01-24-13, 01:16 PM
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The second one could work if the connections are tight. The third might not work if the connections are loose at the second one.

If you pigtail there is no reason to remove them. Leave them in place connected to the receptacles. Many see this a a more reliable method than the screws on the sides of the device to make a connection.
 
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Old 01-25-13, 01:35 PM
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Well, I pigtailed the neutral and hot wires and receptacles 4 through 6 are still nearly dead. Continue with the pigtailing for the remaining receptacles?

Also, if, say I pigtail the wires at #4, and then 5 and 6 work, but they still show as Open Ground on my tester, how do I fix that particular issue?
 
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Old 01-27-13, 07:58 PM
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Well, I pigtailed the neutral and hot wires and receptacles 4 through 6 are still nearly dead. Continue with the pigtailing for the remaining receptacles?

Also, if, say I pigtail the wires at #4, and then 5 and 6 work, but they still show as Open Ground on my tester, how do I fix that particular issue?
In each receptacle box, the ground wires should be spliced (twisted) together, with one or two bare or green pigtails added - one to connect to the green screw on the receptacle and one to connect to the box, if the box is metal.

The white neutral wires should be spliced together with one white pigtail added to connect to one of the two silver screws on the receptacle; the black hot wires should be spliced together with one black pigtail added to connect to one of the two brass screws on the receptacle.

If something doesn't work as it should after you make these changes, tell us what it is and we'll help you fix it then.
 
  #8  
Old 01-28-13, 11:46 AM
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Yeah, that's exactly what I did for the two receptacles that are working, and no luck as of yet for the three non-working receptacles down the line. Unfortunately, I haven't had time to get to those, but I hope too soon.
 
  #9  
Old 01-29-13, 09:01 AM
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Ugh, wonderful. Pigtailed the wiring for non-working receptacles 4 and 5, and made sure everything at the last receptacle in the line was connected properly as well. Also, the boxes are plastic, so there are no ground screws in the box itself.

I'm beyond stumped. Could it be the breaker, and if it is, why would 2 out of the 5 receptacles work fine?
 
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Old 01-29-13, 09:56 AM
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One line going into 4 should read 120 volts. If neither does then the problem is at 3 assuming it has power or the cable between three and four.

To check the cable between three and four disconnect the wires at three. Determine which is a 120 volts and mark the other "to 4".

With the beaker turned off disconnect and separate the wires at 4 and 5. Connect white and black of the previously marked "to4" cable at 3.

With the multimeter set to resistance (ohms) check each cable at 4 for continuity (breaker must be off). One cable should show continuity. If not then there may be a bad cable between 3 and 4.

If you find indications of a bad cable we can do further testing to confirm that.
 
  #11  
Old 02-02-13, 03:46 PM
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I did as you suggested, almost, but I have some questions.

To start, I forgot to disconnect the cables coming into 4 to check the voltage on them. I'll have to get some time to do that.

I followed everything else though, figuring out which cable was running to 4, reconnecting that cable, and disconnecting the cables at 4 and 5. Where I ran into trouble was checking for continuity.

How would I check for continuity at 4? I used my multimeter to check for resistance, but I wasn't sure where to place the prongs. On both cables, when I had one prong touching the ground, and the other touching neutral, it showed continuity. I also switched to continuity mode and that gave off a tone. In checking the ground and hot, or neutral and hot, the multimeter showed infinity. Then I thought I needed to place a prong on one of the wires at 4, and then on the same wire at 3, but the receptacles were too far apart so I used an extension cord at 3. Checking the ground, neutral, or hot at 4 and then same holes on the female end of the extension cord showed no continuity. Could someone tell me how to check for continuity between these two receptacles?

In any event, I reconnected everything once again, flipped the breaker on, and still not enough power at 4, 5, and 6, but 2 and 3 are still good. The only difference this time was that when I checked for voltage at 4, 5, and 6, the multimeter showed 56 volts, instead of 40, which is what it showed in my first post. It seems like something changed, but I'm not sure what.

T
 
  #12  
Old 02-02-13, 07:34 PM
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To test the wires in the cable between 3 and 4 for continuity, find a piece of insulated wire long enough to stretch across the floor between the two boxes. Strip a bit of insulation off each end.

Kill the circuit and disconnect all of the wires in the connecting cable at both boxes. At one of the boxes, use a wire nut to temporarily connect your test wire to one of the insulated wires in the cable. You can then test for continuity at the other box between the wire you connected the test lead to and the loose end of the test lead. Repeat the test for the other insulated wire in the cable.
 
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