Grounded systems in older homes

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  #1  
Old 05-12-01, 11:13 AM
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In the houses built in the 30s/40s/50s where two wires were used and you want to add another outlet, how do you ground the new box. Also what does the term open ground actually mean?
 
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Old 05-12-01, 09:11 PM
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If you have metal conduit and boxes, it's possible that the ground path is through those, as it was a not uncommon practice. If you look in a box with the receptical or switch removed, you may well find a ground wire twisted together and tucked into the back of the box. Check your breaker/fuse panel to see if there are ground conductors there.


If any of these things are true, you can likely convert the two prong to grounded recepticals with minimum fuss. If not, then it can get a bit more involved, with pulling new cables and conductors.

If you mean "open ground" as stated on one of the little plug tester gadgets, it means that that there is no ground path for the ground prong on that outlet.
 
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Old 05-14-01, 10:45 AM
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FYI - Ifyyou would like to change out a 2-prong receptacle to a 3-prong, you must install a GFCI receptacle and label it "No equipment ground". Little stickers saying this come in the package, usually. This is the only way to convert a 2-prong to a 3-prong which is acceptable to the NEC without actually running a new ground wire from your panel to the outlet box.

Juice
 
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Old 05-15-01, 02:49 PM
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juicehead:
would that apply to ALL 2 prong outlets or just the first one in that circuit?
can you not install the GFCI in the first outlet serviced by that circuit and leave the other outlets as is?
thanks
shireesh
 
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Old 05-18-01, 11:55 AM
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You're right, so long as the downstream receptacles are fed through that GFCI. Then all the protected receptacles can be 3-prong, but will require the sticker to be in compliance with the Code. Also, I believe you can only go up to 6 non-GFCIs protected by the first one.

Good question shireesh.

Juice
 
  #6  
Old 05-18-01, 02:27 PM
Wgoodrich
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juice, considering receptacles in a dwelling there is no limit as to how many receptacles are protected by that GFI installed on the first receptacle of the circuit. Also no grounding conductors are allowed on the load side of that GFI so 2 prong or three prong would not matter.

One word of warning considering older wiring styles. You normally can't find the first receptacle on a circuit in that older dwelling unless you install one under the panel, run the wires from the breaker panel through that GFI receptacle then to the branch circuit it protects. This is becuase normal wiring style in older homes were to run from the panel to a light fixture then octopus out to the receptacles. Therefore there is usually no first receptacle on that circuit that exists.

Hope this helps

Wg
 
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Old 05-18-01, 02:42 PM
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For this reason I made sure to advise that "as long as the downstream receps are fed through the GFCI". I should have said "as long as YOU ARE SURE" they are fed through the GFCI. And I know I read somewhere that the maximum recommendation is 6 receptacles. Maybe it was on a cereal box or something, but it stuck with me somehow.

You have mentioned hanging a GFCI below the main panel and connecting a whole general purpose lighting/recep circuit to it in past posts, and I may not have mentioned I think that's a really groovy solution to a common situation. So for the record, I think that's a really groovy solution to a common situation.

Have a nice day.

Juice
 
  #8  
Old 05-30-01, 03:07 AM
Nagoy
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What about running new grounding wire from the breaker panel to ungrounded receptacles? Are there any particular requirements for this?

eg should you run bare wire alongside the existing circuits? Or could you, in theory, take a single length of bare wire and run it all around your house in the crawlspace/attic/or wherever?

More practically, what about if you just added a new grounded circuit near to an existing ungrounded one - could you just run a bare wire between the receptacles?

Mark
 
  #9  
Old 05-30-01, 10:31 AM
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Hi Mark,

There is an interesting discussion on this very topic in a post called "Determining Neutral vs. Ground", where some Code requirements were discussed.

Juice
 
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