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Old 05-28-2009, 09:31 PM   #1
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Defective Ground


Hey folks,
I completed the installation as described in this thread Help with 3way/4way and lights

And the switches work great Thanks TO Everyone! The one thing I did different is instead of running straight to 4 light fixtures I ran to 4 different boxes each with two 15amp duplex outlets so I could plug in the lights. Like I said the lights work and the switches work.

Here is the concern; When I test the outlets with a "plug in" type tester it indicates a "defective Ground". All the grounds are tied together and I physically handled them to see if they had any broken points.

Any help would be appreciated.

Thanks

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Old 05-28-2009, 11:45 PM   #2
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Defective Ground


Does the tester register correctly on other outlets in the house?

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Old 05-29-2009, 12:56 AM   #3
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Defective Ground


I didn't look at the other thread so bear with me if I ask something already answered over there.


Is there a ground wire in each box? Is there a ground wire coming from the panel to the first box? are all the ground screws connected to this wire?

bottom line: a defective ground means you do not have a ground path to the panel.
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Old 05-29-2009, 08:17 AM   #4
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Defective Ground


Quote:
Originally Posted by goose134 View Post
Does the tester register correctly on other outlets in the house?
Thank you for replying. Yes the tester does register correctly on other
outlets. This is in my new workshop.

Quote:
Originally Posted by nap View Post
I didn't look at the other thread so bear with me if I ask something already answered over there.


Is there a ground wire in each box? Is there a ground wire coming from the panel to the first box? are all the ground screws connected to this wire?

bottom line: a defective ground means you do not have a ground path to the panel.
Thanks for replying. Thats okay it (link) was only a quick history and probably and understandably an inconvenience. However, it does have a schematic of the way they are wired...thanks to the experts on this site.

Its a 3way switch - 4way - 4 jboxes with duplex - then the last 3way set up.

There is a ground wire running from the box through the switches through the boxes, connected to all switches and duplexs to the last swithc. All tied together. It is Romex not conduit by the way.

Funny thing is the switches show 120 on the probe tester when touching the ground wire with one and the hot conductor with the other. That does not happen with the outlets. In thinking that the ground may be broken along the cable between the switch and the first outlet I ran another ground wire from the outlet(s) to the ground connecting the switch and still received that red light on the plug in tester showing "defective ground".
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Old 05-29-2009, 08:22 AM   #5
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Defective Ground


Start at the beginning, in the panel, and work your way out, checking for ground at each point along the way. Eventually, you will come to the open spot.

Edit: For some reason, when I responded there were no messages except the first. Rig yourself a test light. If you have a ground at the switch and none at the first box, obviously there is an open in between. If you have ran a test ground, and it still says it's open, then either you don't have a ground to begin with, or the tester is broken.

I bet you used a digital meter at the switch, right? You may have read 120 as a phantom. Use a test light (carefully) to check between hot and ground. If there is no ground, the light will not light.

Last edited by InPhase277; 05-29-2009 at 08:29 AM.
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Old 05-29-2009, 08:35 AM   #6
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Defective Ground


Your ground wire has broken somewhere. Keep on looking, sooner or later, you'll find it.
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Old 05-29-2009, 10:18 AM   #7
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Defective Ground


Find a known good 120v socket.
Run an incand. lamp from the short slot of that socket to your grounds.
If the lamp doesn't light the ground is bad.

If you have a voltmeter, substitute a hair dryer for the lamp. The ground voltage should rise less than 3v with this 10A load when measured with respect to the panel ground.

Last edited by Yoyizit; 05-29-2009 at 10:32 AM.
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Old 05-29-2009, 10:22 AM   #8
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Quote:
Originally Posted by InPhase277 View Post
Start at the beginning, in the panel, and work your way out, checking for ground at each point along the way. Eventually, you will come to the open spot.

Edit: For some reason, when I responded there were no messages except the first. Rig yourself a test light. If you have a ground at the switch and none at the first box, obviously there is an open in between. If you have ran a test ground, and it still says it's open, then either you don't have a ground to begin with, or the tester is broken.

I bet you used a digital meter at the switch, right? You may have read 120 as a phantom. Use a test light (carefully) to check between hot and ground. If there is no ground, the light will not light.
Thanks. I used a test light for checking between hot and ground. The plug in tester is the one with different light indicators. It works on the existing outlets. I also tested as you described between the hot and the ground of each switch. It did show the 120 light at the breaker and first two switches. It thought it was between the last switch and the first box/duplex but running a test ground didnt show that to be true. However, I will redo this test agian to make sure.

I just wanted to make sure I was not missing something.

Thanks.

Thanks again.
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Old 05-29-2009, 10:30 AM   #9
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Quote:
Originally Posted by Yoyizit View Post
Find a known good 120v socket.
Run an incand. lamp from the short slot of that socket to your grounds.
If the lamp doesn't light the ground is bad.

If you have a voltmeter, substitute a hair dryer for the lamp. The ground voltage should rise less than 3v with this 10A load with respect to the panel ground.
I will run a incand. lamp test. Or some kind of rigged light test

Thanks.
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Old 05-29-2009, 10:34 AM   #10
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Defective Ground


I never bought one of those outlet testers. They test maybe 7 ways out of the 32 wrong ways to wire an outlet.
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Old 05-29-2009, 06:01 PM   #11
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Just for a follow up, I found the broken ground. It was actually between the first and second switch. Specificially about an inch from exiting the first switch. Apparently it would work and not work depending on when the box/switch was touched.

Alls good. Thanks to everyone
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Old 05-29-2009, 06:47 PM   #12
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Quote:
Originally Posted by Yoyizit View Post
I never bought one of those outlet testers. They test maybe 7 ways out of the 32 wrong ways to wire an outlet.
Hey Yo, how are you counting 32 ways to wire a receptacle? If there is only one cable with H, N, and G, and you land a wire on each set of screws, that gives a max of 6 possible ways to wire it. If you had two cables, where the grounds were tied together then pigtailed, you would have a max of 5! = 120 combinations. If you had two cables without the grounds tied, you'd have 6! = 720.
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Old 05-30-2009, 01:31 PM   #13
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Quote:
Originally Posted by InPhase277 View Post
Hey Yo, how are you counting 32 ways to wire a receptacle? If there is only one cable with H, N, and G, and you land a wire on each set of screws, that gives a max of 6 possible ways to wire it. If you had two cables, where the grounds were tied together then pigtailed, you would have a max of 5! = 120 combinations. If you had two cables without the grounds tied, you'd have 6! = 720.
I was also counting one wire missing or two wires missing or all three wires missing [the null set].
I can't find the post where some guy worked it out. Might have been on Holt's forum or a different one.
The first time I did it I somehow got 26 combinations.

Just call me yo-yo tits.

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