GFCI Question


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Old 06-22-24, 03:15 PM
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GFCI Question

I am installing a 20a Leviton GFCI outlet the plan is to connect 7 outlets downstream. I wired in the GFCI and 2 downstream outlets. I plugged in devices all 3 outlets work, I then trip the GFCI and the devices all loose power. Seems good, I then use my volt meter and realize the downstream has 70-80v. I understand that the breaker is still on, but since the gfci is tripped shouldn't all the outlets downstream have no power?

I used plastic boxes so I pigtailed the grounds,
 
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Old 06-22-24, 03:24 PM
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It's a meaningless measurement. You can plug something in and confirm there's no power.
 
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Old 06-22-24, 04:55 PM
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Welcome to the forums.

Keep in mind.... a ground fault at any receptacle will cause the GFI receptacle to trip requiring you to remove the plugs from every receptacle to see where the ground fault is. If these receptacles are outside... water in any box will trip the circuit.
 
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Old 06-22-24, 05:12 PM
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These are inside and no water its in a new finished basement, I trip it manually, thye don't trip on there own. I ordered a gfci tester on amazon that I will use tomorrow. It works I want to do it correct, there should be no volts when the gfci outlet is tripped.
 
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Old 06-22-24, 06:03 PM
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I then use my volt meter and realize the downstream has 70-80v
Luke mentioned it, but your digital volt meter is reading 'phantom voltage'. It's techncially induced voltage with basically zero current. But it's an anomaly that most digital meters have.

Either use an analog meter, or add a load (lamp for example), and you'll see it not only doesn't illuminate, but the voltmeter will drop to zero volts.
 
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Old 06-22-24, 06:10 PM
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It's very possible to get a voltage reading using a digital voltmeter due to the meter's high sensitivity.
However.... you mentioned you had to manually trip the GFI receptacle.
Not quite sure what that means.

You don't need a special GFI tester. Connect any load between the hot slot and ground.
I use an old two wire (Wiggy) voltage tester to test GFI's.
I touch one probe to the hot slot and one to the plate screw.
You can use an electricians chandler with any sized bulb as a tester.


Are you wiring the add-on receptacles correctly ?
Incoming power goes to LINE and additional receptacles connect to LOAD.
 
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Old 06-22-24, 06:30 PM
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It's def wired correctly! When I say manually tripped I just mean the test button on the gfci outlet. I may be a idiot, ive done wiring before but I have never put in a GFCI outlet. If i have anything plugged into one of the 3 outlets and trip the outlet via test button voltage is zero. If I unplug the device then I get the partial voltage. HAHAHAHHA electrician chandelier, I have 10 of them as i removed them and put in hi hats from the basement.
 
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Old 06-23-24, 05:28 AM
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Sounds like ghost voltage to me.
FYI: A live AC wire gives off an electromagnetic field. If another wire is placed beside it this field generates a voltage in it. This is how a transformer works but it has a lot of wire length.
So you get a voltage but since the two wires are not beside each other for very long it does not generate any real current. That is why as soon as you plug something into the ghost voltage wire the voltage disappears.
 
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Old 06-23-24, 03:01 PM
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Welp the GFCI randomly stopped working. It was new got a replacement and guess what no phantom voltage at all! It was a Leviton never have problems with there stuff,
 
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Old 06-23-24, 05:18 PM
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Some have LED's that come on when tripped.
That could possibly allow for a ghost voltage.
 
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Old 06-23-24, 10:17 PM
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This is why the real oldies prefer the analogue meter, the ghost voltage does not look so clearly
If you have a lamp or another load at on one of the outlets the reading may be different. No problem to have a modern meter :-) In worst case the ghost voltage has to be killed by putting in a resistor between live and ground, but I do not know the values of that to be within NEC. That solution will also let the make the GFCI trip faster. Just for testing try 56 000 ohms. That will give a load close to 1/4W
 
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