GFI problem


Old 06-28-08, 01:58 PM
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GFI problem

Helping a friend out who was installing a GFI receptacle in kitchen. Thought he mapped out wires correctly but on installation GFI trips. Here is what I found. Box has outlet and 1 switch
3 sets of wires entering box
2 on right --black is hot
2 in middle I believe is for switch to light
2 on left, both have piece of black tape I though was an outlet downstream

Here is what I have found.

1) When 2 on right installed in GFI as Line and 2 on left installed on load, GFI trips

2) With meter when hot on right and that white are tested I get 120V

3) When hot on right and either wire on left are tested I get 120V. So they are both grounds?

4) When hot on right and either wire in middle is tested I do not get 120V

Any advice is appreciated. I assume the black tape on both wire on left means something?

Thanks in advance
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Old 06-28-08, 03:07 PM
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The black tape is indicative of a switch loop. It is not a neutral, but a break in the hot wire to a fixture. It should be attached to a switch controlling a light. What configuration were they hooked up to in the first place? What would the switch control? Were any of the wires nutted together in the box?
Old 06-28-08, 03:43 PM
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OK that makes sense. Then most likely the 2 in the middle are for the load (outlet downstream) and the 2 with tape go to the switch. No nuts in there but I believe he said one of the hot terminals on the original outlet were doubled up so that would be to the switch (line).
Old 06-28-08, 04:43 PM
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You should see if the 120v leads can light a bulb. Meters read phantom voltages (voltages with source impedances way higher than 1/4 ohm).
Old 06-29-08, 10:47 AM
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I tried 2 middle wires to load on GFI thinking was to downstream outlet, ran a hot jumper to black wire on right with tape and connected to bottom of switch and white wire with tape to top of switch. Still tripped GFI but light fixture came on telling me middle black wire is fixture wire as it became hot.

Now I am thinking to have hot wire from load on on GFi to bottom of switch and black wire from middle to top of switch, white from middle to neutral on load on GFI, this will still leave to wires to right with the black tape and an outlet downstream not working.

Am I making sense?


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