Use GFCI for No Ground Outlets?

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  #1  
Old 12-14-04, 12:16 PM
hth
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Use GFCI for No Ground Outlets?

My house built in 1961. All outlets have 3 prongs but except the ones in bathrooms and kitchen (GFCI), all others are open ground when I tested. For my computer room, can I just replace the outlets with GFCIs and it will protect my computers as well? Thx.
 
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Old 12-14-04, 02:32 PM
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Sounds like someone incorrectly replaced the old two prong receptacles with three prong ones. Whoever did this violated code and created an unsafe situation.

My recommendation is as follows. Do one of the following for each incorrect receptacle.

Replace the receptacle with a new two prong receptacle. You can still buy them in most states.

Provide a proper ground for the receptacle. This can be done by either rewiring with new wire or adding a ground wire.

Use a GFCI breaker or receptacle receptacle to provide GFCI protection for the receptacle. Mark each receptacle, including any downstream ones you protect, with a sticker that says "No Equipment Ground".


As for your computers and any other electronic equipment that has three prongs, you will want to properly ground these devices. Electronic equipment that has three prongs on the plug needs a good ground.
 
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Old 12-14-04, 05:11 PM
hth
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to add a groud wire, can I just simple run an extra wire to the ground terminal at the receptacle and tie the other end to a water pipe? Rewiring sound expensive but I will try to have a quote. Thx.
 
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Old 12-14-04, 06:02 PM
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NO! NO! NO! Do not under any circumstances attach a wire to a water pipe and use it to ground anything.

The only place you should attach such a wire is back at the main electrical panel where the ground wires are attached.
 
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Old 12-14-04, 08:19 PM
hth
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Thumbs up

thank you for your help.
 
  #6  
Old 12-15-04, 02:45 PM
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Originally Posted by racraft
NO! NO! NO! Do not under any circumstances attach a wire to a water pipe and use it to ground anything.

The only place you should attach such a wire is back at the main electrical panel where the ground wires are attached.
Why not? The grounding electrode conductor is connected to the water pipe.

Read NEC 2002 Article 250.130(C).
 
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Old 12-15-04, 03:09 PM
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This issue has been dealt with at length in this forum, but I will address it again.

Under normal operating conditions the ground wire does not carry any current. Some devices use the ground wire for reference, but again it does not carry any current.

The ground wire is used by many surge supressors as a path through which to dissipate the excess power that a power surge presents.

For appliances and other devices that use the ground wire, it's purpose is to provide a route back to the source for an accidental short. An example is the metal case of a washing machine. Should a hot wire come loose (say while the washer is spinning), and contact the metal shell of the washer, the circuit breaker will trip because the case is grounded back to the panel via the ground wire.

A problem arises when you use a portion of the plumbing as the return path for this current. The problem is that somebody touching the plumbing (and that means the pipes, the fictures, the water coming from a fixture) may be subject to an accidental shock.
 
  #8  
Old 12-15-04, 03:30 PM
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You may ground an outlet to a water pipe if and only if (1) you attach that grounding wire within 5 feet of where the water pipe enters your house, (2) the water pipe is metallic and in contact with the earth for at least ten feet outside your house, and (3) if the panel grounding electrode conductor is also connected in that same five feet of pipe. These conditions are so specific and prone to misunderstanding that we usually don't offer it as an alternative for the DIYer. But it's okay to do it if you understand the conditions.
 
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