I have a bank — circuit? — of outlets in the kitchen that have stopped working. One of these outlets is a GFCI but it is not tripped. The breakers for all the kitchen outlets have not tripped but I tried resetting them anyway. I took the outlets apart and tested to see if the outlets themselves were bad or if they weren't getting power. One of the outlets, the GFCI, has two wires leading into it that show they have power. The other two wires show they have no power.
How can two of these wires have power and two of them not? How do I know what is broken and how to fix it? Should I simply call an electrician?
Updated details:
The GFCI outlet, I just discovered, was the victim of water leaking across it while we were recently on vacation for thanksgiving. I suspect that has something to do with it.
There are three total outlets. One on the outside of the counter (the snack bar part of the counter) and two on the kitchen side, flanking the sink. To the left of the sink is the GFCI, and it is "upstream" from the other two outlets. Both plugs on the other two outlets are dead. On the GFCI outlet, both plugs are dead but upon taking the outlet out of the wall there is one combination of black /white wire that will produce a light on the 110VAC indicator with my voltmeter. I did not keep close enough track when removing the wires unfortunately so I don't know if this "hot combination" were paired on a single outlet or if they were one wire from either outlet. I'm not 100% sure if it's always this way, but the back panel of my GFCI plug says that the black wires are hot wires and the white wires are simply "white".
Best Answer
Ground-fault circuit interruption (GFCI) receptacles, are not wired the same as regular duplex receptacles. In a standard duplex receptacle, both receptacles and all terminals are directly connected together (Unless modified). If one half of the receptacle is powered, then the other half is as well. With a GFCI receptacle there are LINE side terminals and LOAD side terminals, which are separated by an internal switching mechanism.
The wires feeding the circuit are connected to the LINE terminals, which supplies power to the device. If everything is wired correctly, there are not ground-faults, and the device is not tripped, then electricity is allowed to flow to the receptacles on the device and to the LOAD terminals. So if everything is functioning as it should, there should be be power at both the LINE and LOAD terminals. However, if the GFCI device is tripped, there will only be power at the LINE terminals.
Resetting the GFCI
If the GFCI has tripped, it can usually be reset simply by pressing the RESET button. If you press the RESET button and don't feel/hear a click and/or the button doesn't stay in, it means there is a problem and the internal mechanism is not allowing the GFCI to be reset. You can try pressing the TEST button, then pressing the RESET button again making sure you press the RESET button all the way in. If the device still will not reset, you'll have to try and determine the reason.
Why won't a GFCI device reset?
There are three reasons a GFCI device will not reset.
Wiring is wrong
If the GFCI device is not wired properly (LINE and LOAD reversed, hot and neutral reversed, etc.), the device will not allow a reset.
There is a ground-fault
Obviously, if there is a ground fault, the device will trip as soon as you try to reset it.
There is a problem with the device
If the device has gone bad, it will (should) not reset. Some devices will continue to hold, even if there is something wrong internally. However once they trip, they cannot be reset. Other devices will trip as soon as something internal dies, and will not reset. This is why monthly testing is suggested. If you press the TEST button, and then are unable to reset the device. You'll be made aware of a problem sooner, and can have it repaired (hopefully) before any damage is done.
Rewiring a new device
Before you begin, turn off the power at the fuse/breaker box and make sure it's off.
Locate the supply wire pair
There should be an ungrounded (hot) and grounded (neutral) conductor pair (likely as part of a cable assembly), that supplies power to the circuit. As it sounds like you've already located these, I won't go into detail as to how to locate them here (there are many other answers on the site that explain this procedure).
Terminate the supply wire pair
Terminate load side wires
If there are devices downstream that require GFCI protection, you'll have to connect the wires feeding those devices to the LOAD side terminals on the device.
Set the device
Once all the wires are connected, install the device in the box using the mounting screws. Install the face plate, and turn the power back on.