New Switch Ground

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  #1  
Old 08-26-12, 02:34 PM
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New Switch Ground

Hello again everyone. I'm in the process of replacing some flakey old 10Amp switches with new 15 amp ones. I'm into a double gang box that is housing two switches. There is one #16 grounding wire entering the box wrapped around a cable clamp screw with another few inches hanging loose. The previous switches were not grounded.
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Both of my new switches have grounding terminals - should I ground these switches to the existing grounding wire? Or should I secure the grounding wire to the metal box and run grounding pigtails to the box from each switch? Or do I leave the switches ungrounded?

If it's anything like that #16 wire I found in my receptacle box, it's not really doing anything... (See previous thread on ungrounded receptacles)

Thanks!
 
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  #2  
Old 08-26-12, 02:43 PM
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Have you tested for voltage from hot to neutral, to the ground wire and to the box in this location?

I would bond the ground wire to the box with an approved ground screw, add two pigtails to the end of it, and bond each switch.
 
  #3  
Old 08-26-12, 02:53 PM
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Most of the switches in the home are of a similar setup. When I test hot to the ground wire I get about 12-14 volts. Doesn't seem to matter which switch I test, they're all testing the same.

Why would I only be getting 12-14 volts to ground?
 
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Old 08-26-12, 02:56 PM
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Switches connected to a grounded metal box are not required to have a separate ground attached to them. You still may do it if you want. Follow Nashkat's post.

Why would I only be getting 12-14 volts to ground?
Likely the ground wire is not grounded. If this is the case, you will need to address this.
 
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Old 08-26-12, 03:49 PM
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Why would I only be getting 12-14 volts to ground?
This may indicate a problem with your EGC (Equipment Grounding Conductor) system, including, possibly, your GEC (Grounding Electrode Conductor).

Do you feel secure in doing some tests inside your panel?
 
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Old 08-26-12, 04:39 PM
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I don't have any issues with running test in the panel. It's odd though, as there are many receptacles and other items in the home that are properly grounded.

What should I be checking?
 
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Old 08-26-12, 07:12 PM
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I was going to suggest tests that would help you determine whether you had an adequate grounding electrode. But given that you say that
there are many receptacles and other items in the home that are properly grounded.
here's what I'd look for now:
  • Does your main distribution panel have a main breaker in it, or is that between the meter and the panel?
  • Are there separate ground and neutral bars, or are the grounds and neutrals all landed on the same bar(s)?
  • Are the neutrals each terminated under a separate screw?
  • Are there no more than two grounds under any screw?
  • Are all of the ground and neutral screws properly torqued (there should be terminal torgue values listed on the label inside the panel door)?
 
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Old 08-26-12, 10:12 PM
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The main panel does have a main breaker - 100 amp.
There are not separate neutral/ground bars. Many are combined. I will include a picture below.
Most of the neutrals are under a separate screw, however I believe there are a couple that are combined.
There are a few screws that have numerous grounds.
Not sure on the torque - I would have to check that.

Somewhat random - I did find one ground the was led close to the bar, but not actually attached. This is not on any of the circuits we've been discussing but certainly is a show of the quality of the previous owner when he ran a new circuit. That particular circuit is modern yellow 12/2 NM.

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  #9  
Old 08-26-12, 10:52 PM
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Many errors in the panel. You have many places where you have both ground and neutral in the same hole. You can not have a ground and neutral in the same hole and only one neutral per hole with no more then two grounds per hole. I was trying to find the number of correct connections on the ground and neutral bars but only saw two and those may just look right because of the angle of the camera shot.
 
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Old 08-27-12, 06:23 AM
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Yeah - may be time for a phone call to an electrician to have that stuff sorted out.
 
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Old 08-27-12, 06:37 AM
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An add-in ground bar can be added to give you enough spaces for the grounds. I don't know why part of the right neutral bar was removed.
 
  #12  
Old 08-27-12, 09:40 AM
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What is the make and model of your panel? Is it a Square D QO Loadcenter? If so, finding an add-in ground bar and a replacement for the missing neutral bar section which pcboss pointed out may be fairly easy. I would check with the local supply house that distributes Square D products.
 
  #13  
Old 08-27-12, 02:20 PM
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Thanks everyone. From the research I did, the panel did not come with that segment from the factory. Below is a link to my recent post to discuss that issue.

http://www.doityourself.com/forum/el...utral-bar.html
 
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Old 08-27-12, 02:32 PM
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I thought this panel looked familiar!

From the research I did, the panel did not come with that segment from the factory.
Doesn't matter - there's clearly a place already made there to add one if you need it. You may not need it after you get all the grounds moved to a separate bar.

Or you could just install the add-on bar and sort everything out there. But that's only going to give you 36 terminal locations at the most, if I'm reading the panel correctly. While there's no need to separate the grounds and neutrals in this panel, 36 positions is only enough for 24 120V branch circuits. Dropping below 24 will free up a terminal for a pair of grounds. Is that going to be enough for you?
 
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