GFIs: What are they Good For?
A GFI Plug
The top button is the 'reset' button and the bottom button is the 'test' button
GFIs are those receptacles with the buttons on them. You usually find them in bathrooms and by kitchen counters. These devices exist to save human lives. Yes, that is correct: their only function in this world is to save you from experiencing electrical current flowing through your body.
The NEC requires GFIs in the following locations:
1) Kitchen counters
2) Any outdoor location
3) Any unfinished basement areas
4) Garages
5) Crawl spaces
6) Bathrooms
7) Laundry circuit
A GFI will "trip" when it detects a very slight imbalance of current between the hot and return lines of the receptacle (the two flat blades of the plug). A/C current is normally equal on the hot and return lines. When the current is not the same, it means there is current flowing somewhere else (maybe through you!). So the GFI will automatically trip, disconnecting the power from the outlet. The GFI can detect a very small amount of current imbalance, specifically 6 one-thousandths of an amp (6/1000). Since this is a very small amount, you may not even feel it.
The GFI-required locations are in areas where there may be a water source (very conductive to earth) or bare or concrete-covered earth, which are also potentially conductive. These areas set the stage for the possible shock hazard if you touch a faulty appliance while standing on or touching a good "ground." As soon as a very small amount of current leaks from the faulty appliance through you, the GFI trips, saving your life. Say thank you GFI.
TJ Electric can test and install GFIs for you. These items are often cited as deficient (missing or non-functioning) during home inspections.
Written by Terri Howard of TJ Electric
Phone: (973) 663-1587
www.electriciansnetworks.com/electricians/T_J_Electric/11/973/
