Ground Fault Circuit Interrupter

The National Electrical Code (NEC) requires that any receptacle that is located in a kitchen, a bathroom, on the exterior of the building, or in a garage or unfinished basement, be Ground Fault Protected. The very first question that comes to your mind is: What is Ground Fault Protected?

Before I can answer that question, you have to understand a basic electrical principal, that current needs a complete path, or circuit, from the source of power, through the device (like a light bulb) that is plugged in to it and back to the source. The lamp switch that you use to turn the light on and off is the circuit interrupter, which disconnects the electricity (breaks the circuit) in the cord to the lamp itself. Therefore, with two conductors in the lamp cord, the amount of electricity, or current, that flows through one conductor or blade of the plug, on through the lamp and back through to the other conductor or blade of the plug is equal throughout the circuit. So, under normal circumstances, and due to the laws of alternating current too complex to discuss here, the current flow is equal in both conductors, even though some of the power would be consumed by the light bulb.

It is that current flow in equal quantities in each conductor that is being monitored by a Ground Fault Circuit (GFI) breaker or a Ground Fault Circuit Interrupter (GFCI) receptacle. A GFI is a circuit breaker that responds in the same way as the receptacle, as it too monitors the current flow in both conductors. If either of these two devices sense this difference in current flow, either the GFI circuit breaker trips in the circuit breaker or panel, or the GFCI receptacle trips wherever the GFCI receptacle is located, each cutting the power to the device output. Both have test and reset buttons and are prominently marked as to their use, and both should be tested for proper operation at least once a year. More on that later...

Why should the current in each conductor be monitored? Because if the amounts are different in each conductor, and the electric current is leaking to ground, there is a good possibility the current is being carried by something other that the conductor that brought it to your lamp, or appliance, or whatever. Live conductors in any situation, especially where they are leaking power to ground are always a threat to humans and animals alike. So, if this current was leaking into ground, why would that be problem? It is not initially, except that you are paying money on your electric bill to push electrical current into the ground. But this leak to ground, in and of itself poses a dangerous situation for a person or animal to encounter, possibly resulting in electrical shock, electrocution, and death.

Now suppose that you come across a badly worn extension cord, with frayed insulation, or bare conductors, you pick it up and accidently touch the bare, exposed conductor. If you were standing barefoot on the ground, on your garage or basement floor, in the bath tub, or had your hand on a water faucet, there is the liklihood that you would get an electrical shock. The current would flow through your fingers, up your arm, down your leg to your foot, or whatever was in contact with the ground and then into the ground, onto the garage or basement floor, or back through the water pipe to ground. If you were fortunate, and the current went from your hand, up your left arm, and down your left leg, you would suffer a bad shock. In the alternative, if your right hand came in contact with the live conductor and the current flowed across your chest, through your heart to your left leg, you could have been electrocuted!

So, you ask, what does the GFI or GFCI do to protect you? Remember that the input and output current flow is being monitored, and any current flow in one conductor, not returning to the source, triggers the device to trip. Therefore, if the current is flowing out on one of the monitored conductors, through yourself as described previously, the GFCI receptacle, or GFI circuit breaker would trip out, cutting power and current flow, saving your life. If the device sensed a fault to ground, say an extension cord fell into a puddle, whilst plugged into the GFCI, the device would trip automatically.

That said, a Ground Fault Circuit Interrupter receptacle, or receptacles are now required to be installed in your kitchens, bathrooms, and especially exterior locations, to replace the standard receptacles that are currently installed. If your house was built after 1978 or so, you already have some of these devices in your home.

Back in the days, the only Ground Fault Interrupter product on the market was the GFI circuit breaker, which installed in the circuit breaker panel, in the place of a normal circuit breaker, in those early days just the bathroom receptacles and only the kitchen receptacles within six feet of a water source, or sink, as well as exterior receptacles, such as those on your deck, were required to have GFI protection. We used a loop system then, with a single circuit from the panel to the first bathroom and on to the second bath, and the one required exterior weather-resistant outlet. If the circuit was tripped due to a ground fault, and the circuit breaker had to be reset, and if you have this system in your home now, you know the down side first hand.

Eventually this GFI coverage was extended to cover all of the kitchen receptacles serving the counter top area, even wet bars and other places where receptacles were required that you could come in contact with water pipes, earth or concrete-on-earth, such as basements and garages.

If your home is equipped with normal three prong u-grounded receptacles, see photograph, and you want to safeguard your family and provide Ground Fault protection in these areas, there are a few rules that you must follow........

SAFETY IS RULE NUMBER ONE
UNSCREW THE FUSES
TURN OFF THE CIRCUIT BREAKER
TELL EVERYONE WHAT YOU’RE DOING
EVERY TIME YOU DO ELECTRICAL WORK
IF YOU DON’T KNOW WHAT YOU’RE DOING - CEASE DOING

Never, ever work on live circuits in your home, find your electrical panelboard, locate and either pull the fuse or turn off the circuit breaker for that circuit. If another person can access the panelboard, who might turn the circuit(s) back on, or reinsert the fuse(s), you must post a warning sign that someone is working on the circuit and that the breakers should be left off, and not tampered with.

Sometimes one tenant’s electrical circuits may pass through the other tenants space, and there may be some circuits that are common with another tenants unit. If you do live in a two family home, where another tenant can access these areas, you should contact them directly and tell them what you are doing, ask them to abide and not re-energize any circuits you may be working on. The circuits that you are turning off may appear as blown circuits if the neighbors lights go out without them knowing what you are doing.

Also, if you are working on an electrical box that has more than one device in it, such as 2, 3, or more switches or other devices, or a series of electrical boxes, under one cover plate, beware! There may be more than one circuit in that electrical box. Meaning that you could have one switch with no power, and the one right next to it, for another light somewhere else, would be still energized. If you encounter this situation, and/or if you are not sure, flip every switch under that plate to a different position until you recognize the fixture that is controlled. Once you have determined what is being controlled, leave the controlled lights on and proceed with turning off every circuit breaker necessary until all of the lights go out that are switched from that location. There may be times when you encounter conductors in an electrical box that have nothing to do with the function of that particular switch or other device. This is rare, but always proceed with caution, as if the circuit were energized.