One of the most common deficiencies we find during home inspections, in fact, is the lack of GFCI receptacles where they're required. If you don't know what a GFCI receptacle is, it's the variety with the "Test" and "Reset" buttons. If functioning properly, these devices should protect people from serious shock or electrocution.
GFCI stands for ground-fault circuit interrupter. A ground fault occurs when a current-carrying wire comes in contact with ground. This can occur in a faulty appliance, such as if a loose interior wire touches the metal case and that case is grounded.
If you touch an appliance in this scenario, and you are also grounded - by standing barefoot on the floor, for example, or by also touching a grounded surface - you'll get zapped. You can be injured by even relatively small levels of current running through your body. It takes from 100 to 200 milliamps to kill you. A GFCI will trip at 4 to 6 milliamps, it offers tremendous protection. You might still get hurt, but you're not likely to be electrocuted.
GFCI receptacles work by measuring the current on the hot wire with current returning on the neutral wire. Under normal circumstances, the current is equal on both. When a ground-fault occurs, the current goes to ground via an alternate route and thus the current on the hot and neutral wires is no longer equal. GFCIs detect this and stop power to the receptacle and the appliance.
Today, GFCI protection is required for all receptacles:
•On kitchen countertops
Protection is also required in all laundry, utility and wet bar sink receptacles located within six feet of the outside edge of a laundry, utility or wet bar sink. Luckily, the devices are affordable and electricians can quickly install them. They can also install GFCI breakers in your electrical subpanel. These breakers protect all receptacles, switches and fixtures on a particular circuit. In this scenario, you don't need to replace each receptacle.
We inspect a great many homes in which the original two-wire system is in place. As opposed to new three-wire systems - which have a hot, neutral and ground wire - two-wire systems do not include a ground wire. If your home's receptacles are two-pronged, it's likely a two-wire system. GFCIs still work in a two-wire system. They don't need a ground wire to function. As noted, they measure current on the hot and neutral wires.
It is recommended you test your GFCI receptacles to ensure they're working OK. Simply plug a lamp into the receptacle, and push the "Test" button. You should hear a click and the lamp's light should turn off. Push "Reset" and the light should turn back on. If both don't happen, call your electrician.
GFCI's are cheap insurance for you, your family or your renters and there is simply no good excuse to live without them
Post courtesy of Brian Harley, Buyer's Choice Home Inspection. For more information contact Brian at 416 896 3643.