Replacing 2 prong with grounded receptacles

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Old 01-15-17, 08:38 PM
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Replacing 2 prong with grounded receptacles

Currently have some 2 prong outlets in house.
I have metal boxes, but not conduit.
Can I install a 3 prong outlet and ground it to the metal box?
 
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Old 01-15-17, 08:47 PM
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Welcome to the forums.

That could only be done if the proper BX was run. If you have two wire NM cable there would be no ground at the box.

Do you have an analog test meter or voltage tester ?
Check from both blades of the receptacle to the metal box to see if ground is present.
 
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Old 01-16-17, 03:23 AM
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You can install 3 prong receptacles if they are gfi protected and labeled as no equipment ground.

What is the wiring method?
 
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Old 01-16-17, 09:32 AM
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Are you sure there's no ground wire? Often with old NM cable there is an undersized ground cut off short and wrapped around the box clamp screw. Sometimes these are good enough if you carefully unwrap them and join them up with a wago connector or a crimp and sink a new box ground screw. Careful with the undersized wires as they can be fragile.
 
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Old 01-16-17, 09:35 AM
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To add about the old undersized grounds pull the cover on your breaker box. If you see multiple bare #16 wires going to the neutral bar then you probably have the type of ground Ben wrote about.
 
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Old 03-24-17, 10:30 AM
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Hello,

Do you know where I can obtain the "no equipment ground" stickers? I have a very old house with old two prong plugs.

Thanks!
 
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Old 03-24-17, 10:47 AM
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They are included in the package with a gfi receptacle .
 
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Old 03-24-17, 11:03 AM
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It's also possible that you have what's known as "knob-and-tube" wiring in your house, rather than NM (non-metallic sheathed) cable. This type of wiring uses parallel individual conductors (hot and neutral) on porcelain insulators. There is no bond (ground) wire.

Your options in this case are

1 - Make sure that the knob-and-tube circuit does not use a common neutral with other circuits. If it does, go to option 3.

2 - Install a GFCI breaker in the main panel for the circuit in question. Replace the 2-prong receptacles with modern 3-prong receptacles. Don't connect anything to the receptacle ground screw.

3 - Replace the 2-prong receptacles with GFCI receptacles that are rated to be used with no equipment "ground" (bond). Be careful that the volume of the GFCI receptacle (plus wiring) isn't too much for the old outlet box. If it is, you'll need to change the box. Depending on how many receptacles you have to change, it may be cheaper to pull in new cables and abandon the old wiring.

Be aware that a lot of older homes use Zonolite (vermiculite) insulation in the attic. This is a granular expanded-mica product which is contaminated with asbestos. If that's the case you'll need to call in a licensed asbestos abatement company to make it safe for you to work in the attic. Google "W.R. Grace" and "Libby Montana" to read the horror story.

Cheers,
Brian
 
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Old 03-24-17, 11:50 AM
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Knob and tube should not be used in insulated areas. If it is you have additional issues.
 
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Old 03-24-17, 01:14 PM
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Agree that knob-and-tube should not be in direct contact with thermal insulation. I was thinking of the scenario where the insulation is between the ceiling joists and the knobs are attached to the upper face of the joists, clear of the insulation.

Best regards,
Brian
 
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Old 03-25-17, 11:46 AM
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Do you know where I can obtain the "no equipment ground" stickers?
A new GFCI receptacle will have a few stickers included, but rarely enough for your needs. I believe Hubbell GFCI receptacles include two stickers. I have heard the question, "where I can obtain the "no equipment ground" stickers?," many times and have never heard a definite answer. Seems to me like a company such as Ideal or Gardner-Bender should sell these, but I have never seen them. I think most people end up buying a label making device and make their own.
 
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