Grounding an outlet

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  #1  
Old 02-07-07, 12:04 PM
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Question Grounding an outlet

Our house is about 45 years old an most of the outlets are not gounded. An electrician said a non-gounded box can be replaced with a grounded box. When we asked the Home Deopt guy about this, he said he never heard of a grounded box but said we could ground our outlet by connecting it with copper wire to a copper cold water pipe. What do you think?
 
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  #2  
Old 02-07-07, 12:49 PM
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> An electrician said a non-gounded box can be replaced with a grounded
> box.

Sometimes your existing electrical boxes can be grounded by replacing the wires that feed them, but this is a costly endeavor. I recommend that you only add grounding to receptacles where it is necessary such as those feeding microwave ovens, refrigerators, and computers. If you survey the appliances in your home, you'll find that the majority only have 2-prong plugs. Only those appliances with 3-prong plugs would benefit from grounded receptacles.

A much less costly option is to provide GFCI protection for the ungrounded circuits. This is a legal way of improving the safety of ungrounded circuits which also would allow you to replace the old 2-prong receptacles with 3-prong receptacles.

> When we asked the Home Deopt guy about this, he said he never heard of
> a grounded box but said we could ground our outlet by connecting it with
> copper wire to a copper cold water pipe. What do you think?

Never, ever get electrical advice from Home Depot; the employees have no training and very often give unsafe and illegal advice.

Grounding receptacles to copper pipes is illegal in the U.S. The only way to provide grounding to ungrounded receptacles is to add a green copper ground wire from the receptacle back to the circuit panel box. This is usually more work than simply installing new, grounded circuits to the appliances where grounding is needed.
 
  #3  
Old 02-07-07, 01:11 PM
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Thanks

We don't have any extra places in our service panel for new circuits and we're not in a position to have it replaced right now. I guess we'll just stick with the little adapter screwed into the outlet for plugging in grounded plugs.
 
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Old 02-07-07, 02:03 PM
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A word of caution regarding the screw-in adapter....this WILL allow you to plug in 3-prong plugs, but WILL NOT provide ground protection unless the circuit is wired in metal armored cable, with all metal junction boxes. Basically, the cover screw used to attach the adapter screws to the body of the receptacle and its metal strap. However, if the metal strap isn't ITSELF grounded to metal in any way, such as a metal outlet box, and has no fault-return path back to the panel <armored cable>, then it's not grounded at all. I understand the need to sometimes use these types of adapters, but I think they should outlaw them based on potential safety issues.
 
  #5  
Old 02-07-07, 03:10 PM
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You can easily test to see if one of those 2-3 prong adapters will do any good. Take a neon tester ($2 tester with 2 probes that lights when it has power). Plug one probe into the hot blade of the plug (should be the smaller blade), and then touch the other probe to the metal screw that holds the plate on.

If the tester lights, it means the box is actually grounded (via armored cable most likely), and the adapter will provide a ground.

But then again, if you do this test and the tester lights, you can pretty simply replace the receptacle with a new grounded one, and take a ground wire and screw it into the metal box (using a green grounding screw). After a bit of work you'll have a properly grounded receptacle, that's just as good as rewiring the whole thing.

(There are other posts here that go into more detail - or you can ask)

Of course be sure to shut off the breaker before replacing the receptacle!
 
  #6  
Old 02-07-07, 03:28 PM
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Many houses in the age group you describe have grounded wiring. The ground conductor is smaller that what is current code, but it is there. The accepted procedure then was to pull the ground wire and wrap it around the cable, then clamp the cable and ground wire with the box clamp. What I have done, and I am not saying it is legal, but it does provide a continuous ground if done everywhere in the house. CAREFULLY, (with power off) unwrap the ground from around the cable, pull it into the box and ground it to a screw(not a clamp screw), then connect all grounds together, and add a pigtail to the strap device. Make sure the cable end in the service panel is grounded.
 
  #7  
Old 02-07-07, 04:28 PM
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Originally Posted by Just Bill View Post
Many houses in the age group you describe have grounded wiring. The ground conductor is smaller that what is current code, but it is there. The accepted procedure then was to pull the ground wire and wrap it around the cable, then clamp the cable and ground wire with the box clamp. What I have done, and I am not saying it is legal, but it does provide a continuous ground if done everywhere in the house. CAREFULLY, (with power off) unwrap the ground from around the cable, pull it into the box and ground it to a screw(not a clamp screw), then connect all grounds together, and add a pigtail to the strap device. Make sure the cable end in the service panel is grounded.

There is nothing wrong with this approach. You have a ground wire and you can use it.

If the ground is not there then installing a GFCI receptacle is a much safer than using the adapter. It is also code compliant if you stick the little sticker saying ungrounded receptacle on the front surface.
 

Last edited by joed; 02-07-07 at 07:15 PM.
  #8  
Old 02-07-07, 06:19 PM
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Just Bill. This is the best aproach, and code compliant. If it is there..Use it.
 
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