Replacing 2 prong with grounded receptacles


  #1  
Old 01-15-17, 07:38 PM
P
Member
Thread Starter
Join Date: Jan 2017
Location: United States
Posts: 1
Upvotes: 0
Received 0 Upvotes on 0 Posts
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?
 
  #2  
Old 01-15-17, 07:47 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 64,939
Received 3,952 Upvotes on 3,545 Posts
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.
 
  #3  
Old 01-16-17, 02:23 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 13,976
Received 194 Upvotes on 170 Posts
You can install 3 prong receptacles if they are gfi protected and labeled as no equipment ground.

What is the wiring method?
 
  #4  
Old 01-16-17, 08:32 AM
I
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 9,785
Upvotes: 0
Received 45 Upvotes on 43 Posts
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.
 
  #5  
Old 01-16-17, 08:35 AM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 29,711
Upvotes: 0
Received 15 Upvotes on 13 Posts
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.
 
  #6  
Old 03-24-17, 09:30 AM
T
Member
Join Date: Mar 2017
Location: USA
Posts: 1
Upvotes: 0
Received 0 Upvotes on 0 Posts
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!
 
  #7  
Old 03-24-17, 09:47 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 13,976
Received 194 Upvotes on 170 Posts
They are included in the package with a gfi receptacle .
 
  #8  
Old 03-24-17, 10:03 AM
O
Member
Join Date: Mar 2017
Location: Canada
Posts: 10
Upvotes: 0
Received 0 Upvotes on 0 Posts
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
 
  #9  
Old 03-24-17, 10:50 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 13,976
Received 194 Upvotes on 170 Posts
Knob and tube should not be used in insulated areas. If it is you have additional issues.
 
  #10  
Old 03-24-17, 12:14 PM
O
Member
Join Date: Mar 2017
Location: Canada
Posts: 10
Upvotes: 0
Received 0 Upvotes on 0 Posts
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
 
  #11  
Old 03-25-17, 10:46 AM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: United States
Posts: 9,871
Received 185 Upvotes on 166 Posts
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.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: