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Old 02-24-2012, 04:14 AM   #1
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Is this safe (GFCI in old home)

Ok so I have 4 wires in my box... 2 white 2 black. no ground but it is a metal box that I think is grounded. Anyways, I figured out which set was line and which set was load and hooked up the 4 wire but left ground alone(nothing hooked to the ground screw on the GFCI)

Am I getting any kind of actual protection? Am I gonna burn my house down? Anything else I need to know?


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Old 02-24-2012, 04:38 AM   #2
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That's the way to do it when no ground wire available.

Actually if you get the line and load mixed the GFI won't reset.
Make sure you test it with the button.

It will work as intended without the ground wire.
The problem is that any fault current doesn't have an easy path to ground. It will get there. Hopefully not hurting anything.


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Old 02-24-2012, 07:32 AM   #3
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There is no guarantee that the metal box is grounded. The wiring method would need to supply a grounding means before the box is grounded. Otherwise it would just be floating.
Answers based on the National Electrical Code. Local amendments may apply. Check with your local building officials.
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Old 02-24-2012, 07:38 AM   #4
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But it is the recommended way for some protection in a groundless
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Old 02-24-2012, 07:53 AM   #5
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Because there is no ground the gfci will protect you from electrocution but not shock. By that I mean if there was a ground wire installed and an effective ground fault path established any fault to ground would trip a breaker. This would protect you from both shock and electrocution as the branch circuit would be de-energized. If however no ground is present and only a gfci then the gfci would sense any milliamps of leakage current between the hot and neutral. So if a ground fault was present that would not clear due to the absence of a ground fault path .. and you touched any bonded metal that was energized you might receive a slight shock just before the gfci tripped. The important thing is you won't receive a fatal shock.

Just remember that a gfci breaker protects the entire circuit and a gfci receptacle only protects load side of the receptacle.
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Last edited by Stubbie; 02-24-2012 at 07:59 AM.
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