GFCI's - What do they do?

Home Inspector with Another Look Inspections, LLC

What is a Ground Fault Circuit Interrupter? 

If you've had an inspection in the recent past you've probably heard the term GFCI.  What is that?  GFCI is short for Ground Fault Circuit Interrupter.  In simple terms this a safety device that is recommended as an industry standard.  This device detects the amount of electrons (electrons are what make up electricity) flowing through a magnetic field. These devices sense as little as 4-5 milliamps of current and trip in about 1/30 of a second. Very little current escaping the circuit can cause the device to trip.

How does a (GFCI) work?

Here's an example of how the device works:  Let's say that you're in a hurry and have to wash your hands.  Someone has left the hair dryer plugged in and on the edge of the sink.  You accidentally bump the dryer at it falls under the water.  Your reaction is to grab the dryer...whoops.  Having a working properly wired GFCI device in place will have just saved you from serious injury or worse.  In far less time that it would take you to realize that you are being shocked, the GFCI device has safely shut off the current to the dryer.

As a rule of thumb, GFCI protection devices should be placed within 6 feet of water dispensing areas (all sinks, bath tubs, etc.), and at all exterior locations including decks, near pools and garages.  If there is a question as to where they need to be placed, ask your electrician as they know the code for your municipality.


Most manufacturers recommend that you test your GFCI devices once every 30 days.  To test to see if the device is operative press the "test" button.  This should make the device activate.  Then simply press the "reset" button and you're back in business.  All is fine provided the device is properly wired within the electrical circuit.

How can I check if it's wired correctly? 

A qualified person such as a home inspector can test the receptacle to make a general evaluation.  A licensed electrician is the person that would analyze, troubleshoot and correct problems with electrical circuits and devices.

Recall information:

Go to the Consumer Product Safety Commission web site regarding Murry/Siemans recall.





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All rights reserved. Another Look Inspections, LLC. 2005
Last updated 5/29/2005

Comments (4)

Armando Rodriguez
Orlando Homes 4 Sale, Real Estate Broker-GRI
They're usually in the wet areas of a home. Bathrooms, kitchens etc. I think they short out much quicker than a circuit breaker.
Jul 16, 2007 04:05 AM
Donna Harris
Donna Homes, powered by JPAR - - Austin, TX
Realtor,Mediator,Ombudsman,Property Tax Arbitrator
What I find interesting is how they decide which outlets are tied together.  Many times, a guest bath is tied to the reset button in the master bath.  Most times in my area, the outlets at the front and back doors have a reset button in the garage... why can't these reset buttons be closer!  I love it when the reset button for an upstairs bathroom is in a bathroom downstairs.  How did they get the wires to move in just directions... doesn't the cost of wires add up?
Jul 16, 2007 04:26 AM
Sam Vladova
Another Look Inspections, LLC - Wentzville, MO

Electricians are tradesmen and with that I can only say there is not a standard way to set these receptacles up for convenience.  Electricians get paid on speed that they can do a job and we all expect it to be safe job.  The perferred method in more affluent homes in my area is to have the GFCI reset in the same room where the outlet is needed to controlled.  Unless the muncipal building authority says otherwise, the electrician can allocate GFCI devices up to the manufacture's instructed amount of down stream outlets protected with a single device.  This mease that you may have the GFCI device in the garage controlling the upstairs hall bath counter outlet. 

I agree that wire costs and labor add up quickly and personally I think if the electricians really put a pencil to it they would find a cost saving by adding a $12 -$15 dollar device rather than taking the time and effort to back wire these circuits.  Unfortunately this is not the world we live in and expect to hunt in your home for the tripped GFCI until things change.

Jul 16, 2007 07:20 AM
Fred Griffin Florida Real Estate
Fred Griffin Real Estate - Tallahassee, FL
Licensed Florida Real Estate Broker

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