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How does a GFCI receptacle work?

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Answered 2010-02-08 15:14:50

GFCI (Ground Fault Circuit Interruptor)

A GFCI receptacle is designed to prevent electrical shock. This device constantly monitors the current flow in the hot and neutral conductors.

The current in the hot and neutral conductors should match. If the current flow doesn't match, the device disconnects itself and any receptacles it protects from the electrical source.

Because the device does not actually check the ground current, it can be installed without a ground wire. A GFCI wired in this manner, or any receptacles protected by it, is required to be marked "NO EQUIPMENT GROUND" and is an allowable method of changing two-wire ungrounded receptacles to three-wire grounding receptacles.

If you do this work yourself, always turn off the power

at the breaker box/fuse panel BEFORE you attempt to do any work AND

always use an electricians test meter having metal-tipped probes

(not a simple proximity voltage indicator)

to insure the circuit is, in fact, de-energized.




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Related Questions

Can I install a GFCI receptacle from an existing receptacle in the basement?

Yes, there is no reason why this can not be done. In fact a benefit of this is that every receptacle downstream from this new receptacle will also be protected by the GFCI receptacle.

What might happen if the line and load connetions of a feedthrough gfci receptacle were reversed?

Most probably the receptacles downstream from the GFCI would not be protected by the GFCI receptacle.

Do you need a gfci outlet if you have a gfci breaker?

Not if the GFCI breaker is supplying the circuit you are wanting to put the GFCI receptacle into.

What is a GFCI receptacle?

A GFCI receptacle is a ground fault circuit interruptor.For more information see the answer to the Related Question shown below.

If your wall receptacle has tripped but not at the circuit breaker how can this problem be repaired?

If it's a GFCI receptacle and the button is not resetting then change the GFCI outlet.

How do you install multiple GFCI receptacles?

A GFCI receptacle can extend its protection to regular receptacles connected to the output side of the GFCI. Each actual GFCI receptacle should be directly connected to a breaker in electric panel.

What is the weight of a GFCI receptacle?

8 ozs. and will vary by mfr. for an in-wall receptacle.

Can a gfci breaker be used with a gfci outlet?

Yes but it's redundant and may cause unnecessary "tripping" of the circuit. The GFCI circuit breaker is intended to protect an entire receptacle circuit whereas a GFCI receptacle is designed to protect only that receptacle and any which are provided power from its load side. (downstream)

If I have 20 amp GFCI receptacle and would like to add another receptacle to the GFCI Does the new plug also need to be 20 amps?


How many miliamps to trip out a GFCI?

GFCI receptacle are designed to trip on 5 milliamps.

How far do you put a GFCI from water?

How far do u put a GFCI receptacle from water

Will another electrical outlet that is in line with a GFCI outlet cause it to kick off?

A down stream receptacle that is connected to the upstream GFCI will be protected. If the downstream receptacle senses a fault the upstream GFCI will trip.

What does the term GFCI receptacle stands for?

The term GFCI stands for Ground Fault Circuit Interrupter.

How do you reset a GFCI outlet?

Push the reset button in the center of the receptacle. When you first power up a GFCI receptacle is will automatically trip, just reset and you will be good to go.

What is the function of ground fault circuit interupter?

The function of a GFCI is any fault to ground will automatically trip the circuit. For example, if a hairdryer is plugged into a GFCI receptacle and it is dropped into a sink of water, the GFCI will shut down power to the receptacle.

Can you install an electrical switch before a gfci?

Yes! you can install an switch a head of a GFCI receptacle. This installation is common in some applications to turn on an outside receptacle to control Christmas lights.

What is wrong if you installed a gfci in the bathroom according to instructions and when the test button is pushed the lamp plugged into the adjacent bedroom socket goes off?

The "TEST" button is there for you to check the GFCI is operating correctly. When you test the GFCI using its Test button it should trip to break the circuit. Then anything connected to that circuit will have no power. It sounds like the light in the other room is wired to the same circuit as the one you are working on, so, if the GFCI is tripped - such as when you press the Test button - no outlet in that circuit will be able to work until you reset the GFCI using its "RESET" button.If what happens is as was just described then your GFCI is working as it was designed to do. If you are talking about a GFCI receptacle, and wired the receptacle as it shows you how to on the instruction sheet, then everything down stream from the receptacle is protected, along with the actual receptacle that you just installed. The bottom set of terminals on the receptacle that states the word "load", is where the wires leaving the receptacle box should be connected to. Incoming power to the top terminals of the receptacle outgoing power to the next receptacle to the bottom terminals. This allows the GFCI receptacle to protect every other receptacle that is connected down stream on that circuit. If you check closely to the other receptacles that are connected, you will find that they also will be off when you push the test button. ----- As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed. Before you do any work yourself,on electrical circuits, equipment or appliances,always use a test meter to ensure the circuit is, in fact, de-energized. IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOBSAFELY AND COMPETENTLYREFER THIS WORK TO QUALIFIED PROFESSIONALS.

Why did the Gfci reset but still no power to outlet?

When power is first applied to a GFCI receptical they will trip the reset. This has to be reset to power the receptacle. If it was wired wrong then the breaker feeding the receptacle may have tripped. Check the source for the receptacle at the electrical panel to see if the breaker tripped the circuit.

May a GFCI receptacle be installed as a receptacle in an old installation where the 2-wire circuit has no equipment grounding conductor?

Actually, yes. The GFCI does not need any ground; it measures "leakage", i.e., an imbalance, regardless of whether there is "ground". The National Electrical Code permits installing a GFCI to replace a completely ungrounded receptacle. Others have said: No. The GFCI is designed to measure an unintended path to ground. Without a good ground reference this is not possible.

How do you check a ground fault interrupter?

Both GFCI breakers and receptacles have a button you can push to test it. You can also get receptacle testers with a GFCI tester on them.

Do you need a gfi plug for a spa if it is being plugged into a gfi circuit?

If your spa is connected with a GFCI circuit breaker you will not need the GFCI receptacle.

How do you test and reset a GFCI receptacle?

GFCI (Ground Fault Circuit Interruptor) A GFCI receptacle can be tested with the built-in test button, which will cause a small ground fault, tripping a properly working device. GFCI receptacles should be tested monthly. GFCI receptacles can also be tested with a plug-in type GFCI tester. This tester has a GFCI trip button on it which accomplishes the same thing as the built-in test button. Your local inspector will usually test with this method. If your receptacle is tripped, it should reset by pressing in the reset button. If it doesn't, the device is wired incorrectly, has a faulty load plugged into it, or is simply in need of replacement. ---- IF YOU'RE NOT ALREADY SURE YOU CAN DO THIS JOBSAFELY AND COMPETENTLYREFER THIS WORK TO QUALIFIED PROFESSIONALS.If you do this work yourself, always turn off the powerat the breaker box/fuse panel BEFORE you attempt to do any work AND always use a meter or voltage indicator to insure the circuit is, in fact, de-energized.

What is the proper way to test a receptacle?

The simplest way to test a receptacle is to use a plug-in type receptacle tester. This tester indicates either proper operation or common miswirings of the receptacle. If the receptacle is a GFCI, there is a special type of plug-in tester that has a GFCI trip button on top. This tester indicates the same things as the other one. In addition, you can press the test button to create a small ground fault, which will trip a properly operating GFCI. ---- IF YOU'RE NOT ALREADY SURE YOU CAN DO THIS JOBSAFELY AND COMPETENTLYREFER THIS WORK TO QUALIFIED PROFESSIONALS.If you do any work yourself, always turn off the power at the breaker box/fuse panel BEFORE you attempt to do any work and always use a meter or voltage indicator to insure the circuit is, in fact, de-energized.

What is the electrical symbol for a GFCI receptacle?

== == == == It's a receptacle symbol, usually with "GFCI", "G", or "GFI" written under it. To find out exactly which symbol is used on your prints, look at the electrical legend, which is normally page E-1, E-001, etc.

If a 20 amp receptacle mounted outside must be?

If a 20 amp receptacle is to mounted outside it must be enclosed in a waterproof box and cover and be of the GFCI type.