Legal Receptacle Grounding

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  #1  
Old 03-29-15, 11:33 AM
Gen
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Legal Receptacle Grounding

I'm seeing older outlets in metal boxes. They've got the incoming romex grounds tied to the box, (usually the cable clamp screw) and no jumper to the outlet itself. So via the metal box it does still show a grounded reading on a outlet tester. Is this still legal? Otherwise what is acceptable? Outlet ground screw to green screw to box threads? or to green clip on box edge? Thanks!
 
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Old 03-29-15, 11:46 AM
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As long as you are using self grounding receptacles/switches tying the grounding electrode to the box via a green screw in the threaded hole is acceptable. Older applications will see the green grounding clip, although I am not sure how universally accepted they are. Ideally, leaving a pigtail from the grounding screw to the switch/receptacle is the right way to go. Really, the wire was there, and the installer had to cut it off. Why?
 
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Old 03-29-15, 11:50 AM
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Why? because it was originally 2 prong UG outlet. But is it legal to just let the box be the ground bridge?
 
  #4  
Old 03-29-15, 11:50 AM
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Ground

Connect twp pigtails to the incoming Romex ground. Connect one pigtail under a green ground screw which is screwed into a threaded hole in the box. Connect the other pigtail to the ground screw on the receptacle.

Sorry, Larry and Gen. I type too slowly.
 
  #5  
Old 03-29-15, 01:44 PM
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Using the cable clamp screw is not legal , but commonly done. The ground screw does not have to be green either.
Geo
 

Last edited by pcboss; 03-29-15 at 03:28 PM.
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Old 03-30-15, 07:30 AM
Gen
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Thanks for all the replies. I do still however have the unanswered question: Is it legal for the box, as I described, to be the bridge to ground? --With no jumper from the outlet ground screw. This set-up does read as grounded.
 
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Old 03-30-15, 08:01 AM
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Chandler answered correctly in the first reply. The metal box is the legal ground. If you use self-grounding receptacles, then the mounting screw picks up the ground from the box. For regular receptacles, you need to run a pigtail from the ground screw on the receptacle to a ground screw on the box. Ideally the ground screw should be a tapped, 10-32, green, hex head screw. In older homes, most any screw in the box including the clamps was used as a ground screw.

self-grounding receptacle has copper clips on the mounting screw:
 
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Old 03-30-15, 11:42 AM
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Great thanks for clarifying Chandler's input!
 
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Old 03-30-15, 02:31 PM
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Yeah, thanks, Ben .....................
 
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Old 04-01-15, 07:16 PM
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Well....

OK so now I wonder if my actual question was answered correctly based on seeing
Chandler bang his head.......
 
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Old 04-01-15, 07:18 PM
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No, I just didn't think my comment needed clarification. All in jest. You're good.
 
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