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My knowledge of electric is minimal. Obviously.

I am trying to replace an old two prong outlet in the bathroom with a GFCI outlet. The panel has been upgraded at some point, and the metal outlet box in the bathroom is grounded. This was confirmed by an electrician and my multimeter. I'm assuming the outlet is grounded via metal conduit that I can't see, as there are no ground wires present in the box.

Coming into the box from the top is a black and white wire. I'm assuming this is the Line. Going out the side of the box is another black and white wire which should be the Load.

So I wired the top black and white wires to the corresponding black and white Line screws on the GFCI. And I wired the other black and white wires accordingly to the Load screws.

And then I ran a 12g pigtail from the ground screw on the GFCI outlet and screwed the other end into the back of the metal electrical box.

Then I turned on the breaker but no love. I pushed the test and reset buttons on the GFCI but still nothing.

Where did I go wrong? And obviously I should have had an electrician do this but here we are.

My GFIC outlet is brand new btw.

Please and thank you!
 
FYI-
A GFCI receptacle works on the principle of tripping from a voltage imbalance between the "hot" (any color but white or green) and the neutral (white) wire which is the return path to the service panel hence the term, "Ground Fault Circuit Interruptor". Also, a ground wire is not required for it to operate properly, but is desirable if available.

It sounds like you may need to swap the wires and put the wires coming from the top onto the load terminals (brass = hot wire to outgoing load), silver= neutral wire to outgoing load), and the wires coming from the side onto the line terminals (black = hot from panel, silver = neutral from panel).

Concerning electricity, DON'T ASSUME! The best way to tell is to use a multi-meter and see which black wire is "hot" (set your meter to 120vac and put a test lead on each of the pairs to see which one shows 110-120vac). Also, do NOT short the black and white wires together while the breaker is on!

Hope that helps!
 
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A GFCI requires a ground wire. If there is no ground the GFCI (ground fault circuit interrupter) will detect a ground fault and interrupt the circuit... i.e. trip immediately.

You will need to figure out some way to run a ground wire to the outlet... and every subsequent outlet on the circuit. Without a ground wire to every outlet on the circuit a GFCI is useless... it wouldn't be giving any protection even if you did get it to not trip.

You can look up the current codes but I am pretty sure metal conduit can no longer be used for grounding outlets. If there is metal conduit from the box to the panel you might be able to tie a string to the current cable, pull the current cable out then use the string to pull a 3 conductor cable with a proper integrated ground. If there is conduit end to end you can pull 3 THHN wires (black, white, green) instead of a cable (Romex) if you prefer... individual wires are usually much easier to pull through conduit than a cable (Romex).
 
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GFCI's don't require a ground. They're a code acceptable replacement for a two pronged (ungrounded) receptacle.

Did you test the existing wires to see which ones are hot with the power on?
 
If you don't know where the outgoing wires lead to, I would just wire up the GFIC as line only and not load protecting the outgoing lines.
I was once asked to figure out why half of the interior lights were not working in the house next door to me.
Seems the previous clueless owner had wired a GFIC outlet outside behind the garage, which had tripped somehow.
Half the interior lights were hitched to that GFIC and the bush planted next to it had covered it up.
It took a couple of hours tracking it down.
 
Make sure all the smoke detectors are working and ready for serious protection.do your research using reputal knowledge and practices. Don't let joe biden burn your house down..
 
A GFCI requires a ground wire. If there is no ground the GFCI (ground fault circuit interrupter) will detect a ground fault and interrupt the circuit... i.e. trip immediately.
This is both untrue and a significant misunderstanding of how a GFCI outlet works and why it trips.

(The term "GFCI" can be misleading. Imo, the technology is better understood by its other name, that's more commonly in use outside the US: RCD, or Residual Current Device. Because what it's actually detecting is, essentially, current that hasn't reached its intended destination.)

A GFCI trips when the current across the hot and neutral terminals is not equal in both directions, which indicates a leakage of current. Leakage to ground will trip it, certainly, but so will leakage into a person. That is to say, the underlying problem that caused current to leak might not (and typically does not) have anything to do with any fault in the ground connection. And the fact that a GFCI will trip in response to something other than current leakage to ground is why, as pointed out above, a GFCI can be installed in a receptable that doesn't have a ground connection.

In fact, it's a good idea to replace a two-prong outlet with a GFCI. It makes that outlet safer, since now you have a device that can stop current flow much more quickly than the breaker at your panel can. In a worst-case scenario, that can make all the difference between, "Argh, f**k, that hurt!" and ventricular fibrillation leading to death.
 
G round
F ault
C ircuit
I nterrupter

If the ground comes loose or the neutral comes loose, the gfci will trip.

That is my experience.
 
For those still reading this thread, Not all grounds are created equal.
In order for Breakers, GFI's to work properly for ones safety when something malfunctions,
The ground wire in an outlet or switch box must tie directly to the ground bus bar inside the breaker box. if instead, it is hooked to a separate ground stake, or a water pipe, it must be corrected or the circuit disabled.
I've seen several old two wire houses and knob and tube houses un knowledgeable home owners had added a ground to outlets by connecting them to the nearest pipe or adding a stake outside near by to hook them to. . NO! NO!
This supposed thrift is dangerous!
 
I had an issue where I was seeing low voltage on some of the outlets in our kitchen. I bought a GFCI tester that diagnoses common wiring problems. I just replaced one GFCI in our kitchen to get the outlets working again. I do have a voltage meter from Fluke that I bought when I was in college decades ago and it still works.

https://www.amazon.com/Receptacle-Tester-Klein-Tools-RT210/dp/B01AKX8L0M/ref=sr_1_5?sr=8-5

I bought my GFCI tester from either Home Depot or Lowes years ago.
 
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Coming into the box from the top is a black and white wire. I'm assuming this is the Line. Going out the side of the box is another black and white wire which should be the Load.
These are the two key sentences.
"Assuming" the top pair of wires are the line and the side pair of wires "should" be the load.
If the line/load are backwards your circuit won't work.
You must first ascertain which pair of wires are the "real" line.
And this sentence in post #11 is correct: "A GFCI trips when the current across the hot and neutral terminals is not equal in both directions".
The green/ground wire does not affect the operation of a GFCI, what it does do is provide a low resistance path back to the "source" where the grounds and neutrals are tied together.
 
A GFCI requires a ground wire. If there is no ground the GFCI (ground fault circuit interrupter) will detect a ground fault and interrupt the circuit... i.e. trip immediately.
False as others have stated. GFCIs are required for old 2 wire 120 volt circuits without a separate equipment ground wire.
What ever you do don not use the neutral as a ground!!
You can look up the current codes but I am pretty sure metal conduit can no longer be used for grounding outlets. If there is metal conduit from the box to the panel you might be able to tie a string to the current cable, pull the current cable out then use the string to pull a 3 conductor cable with a proper integrated ground. If there is conduit end to end you can pull 3 THHN wires (black, white, green) instead of a cable (Romex) if you prefer... individual wires are usually much easier to pull through conduit than a cable (Romex).
Not legal to put cable (Romex) in conduit. Mixing of 2 different wiring systems. Exceptions for short piece of
conduit used for physical protection. Conduit is acceptable as an equipment ground.
I think that if you give electrical advice you should have to put your BCD License # down. :D
Good point. Retired 40 years IBEW electrician. State of Oregon General Supervisor Electrician license and
Washington state General Master Electrician.
 
I think that if you give electrical advice you should have to put your BCD License # down. :D
However guns, medical/ first aid, automotive, plumbing, boating, religious, building construction, survival, child rearing, fiduciary advice, general gossip and opines on any other subject, are exempted.:rolleyes:
 
False as others have stated. GFCIs are required for old 2 wire 120 volt circuits without a separate equipment ground wire.
What ever you do don not use the neutral as a ground!!

Not legal to put cable (Romex) in conduit. Mixing of 2 different wiring systems. Exceptions for short piece of
conduit used for physical protection. Conduit is acceptable as an equipment ground.

Good point. Retired 40 years IBEW electrician. State of Oregon General Supervisor Electrician license and
Washington state General Master Electrician.
No argument. - what about running conduit in rooms where electrical wires cannot be installed in the wall. Is it OK to run romex through metal conduits in these cases. I know we did this when I was in the Navy as an electricians mate.
 

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