Article
Ground fault circuit interrupters (GFCIs for short … no pun intended) 
are nothing new. They first became a Code requirement in the 1970s, 
required for outdoor receptacles and around swimming pools. Actually, 
they were required for underwater pool lighting earlier than that.<br><br>Nowadays, they're required in a lot more places: kitchens, bathrooms, garages, and that dank, dark basement of yours.

GFCI – Killing the Buzz Before It Kills You

Steve Maurer, IME
Ground fault circuit interrupters (GFCIs for short … no pun intended) are nothing new. They first became a Code requirement in the 1970s, required for outdoor receptacles and around swimming pools. Actually, they were required for underwater pool lighting earlier than that.

Nowadays, they're required in a lot more places: kitchens, bathrooms, garages, and that dank, dark basement of yours.

In fact, if the potential for moisture is prevalent, you can bet a GFCI will be required, if not now … in the future.

When I rewired this old house of ours, I installed GFCI breakers in the panel. Sure, it was a bit pricier than just a GFCI receptacle. But not all that much. My thinking was this: if a receptacle goes bad, will I be tempted to install a cheaper, non-GFCI receptacle instead of the more expensive GFCI model?

I don’t need to worry … I'm covered.

Besides, everything on that branch circuit will be protected.

Everything.

So, what is a ground fault?
According to a Consumer Protection Safety Commission (CPSC) fact sheet:
"A ground fault is an unintentional electrical path between a power source and a grounded surface. Ground faults most often occur when equipment is damaged or defective, such that live electrical parts are no longer adequately protected from unintended contact. If your body provides a path to the ground for this current, you could be burned, severely shocked or electrocuted."

For example, let's say a wire came loose in your washing machine and contacted the metal case. It may not be enough to trip the breaker. But it could be more than enough to shock you when you touched the machine.

The GFCI prevents that shock by shutting off the receptacle, not the breaker.
It doesn't take much to trip the GFCI … somewhere around 5 milliamps. And it doesn't take long, either. In less than a blink of an eye, you've been protected from a potentially life-threatening shock.

How does a GFCI work?
The name is kind of misleading. The device isn't looking for a short to ground. Instead, it's looking for an imbalance of current between the circuit's ungrounded (hot) and grounded (neutral) conductors.
So it should trip long before a dead short happens.

It also means that GFCI receptacle can be used on old house 2-wire circuits and still do its job.
Remember, however, that it's measuring the internal load of the receptacle. If you short yourself out between the hot and neutral … you'll still get shocked.

Don't forget to test your GFCIs
Just like your smoke detector, you need to check your GFCI receptacles and breakers periodically.

(You are testing the smoke detector, right?)

That's what that little push-to-test button is for. It's not that hard to push it when you plug in something. I mean, it's right there. If it kills the power, just push reset.

And if it doesn't trip … it's time to replace it. They can go bad, just like anything else.
According to that same CPSC fact sheet, you should test your GFCIs:

  • After installing them
  • At least once a month
  • After a power failure (transient voltage can damage the internal components)
  • And of course, according to the manufacturer's instructions
By the way, if your outside outlets aren't GFCI protected, you might want to get a portable one to plug in first, then your extension cord. Whether it's an electric hedge trimmer, lawn mower, garden tiller, or party lights, GFCIs are good things to have.

Ground fault circuit interrupters. Use them.

Kill the buzz … before it kills you.
Photo courtesy of Molex®
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