For decades, ground fault circuit interrupters (GFCIs) have saved thousands of lives and have helped significantly reduce the number of home electrocutions by about fifty percent.
Intro to GFCI
Ground Fault Circuit Interrupters (GFCIs) were first introduced in Canada over 40 years ago. When these GFCI breakers detect an electrical current flowing through unintentional paths such as water or people, they shut off electricity to that outlet.
GFCI breakers monitor an imbalance of current between the grounded and ungrounded conductors of a circuit. If the current entering a GFCI is different than the current leaving the GFCI, the unit de-energizes the circuit. GFCI outlets are easily identified by the reset and test buttons located on the outlet.
How GFCI Works?
Usually a normal electrical outlet has two vertical slots and a round hole just below them. The larger “left slot” corresponds to “neutral and “right slot” is called “hot”. The third, round hole is the “ground”.
Normally, electricity flows from hot to neutral in the outlet. The GFCI works by measuring the current leaving the hot side of the power source and comparing it to the current returning to the neutral side.
If they are not equal, this means that some of the current is flowing along an unintended path possibly through water or through a person.
The GFCI detects imbalance in the current flowing from hot to neutral, imbalance in the current flowing from hot to neutral and quickly cuts off electricity, thus reducing the risk of electrical shock.
The sensor inside a GFCI detects the difference between the current flowing to the appliance and the current flowing from the appliance.
If the electricity flowing into the circuit differs by as small as 4 or 5 milliamps from that returning, a GFCI quickly turns off all power by tripping a relay within it within a few hundredths of a second, much before the user hardly feels the shock.
When the problem is corrected, GFCI’s can later be reset to restore power to the affected circuit.
If the problem still exists and GFCI continues to “sense” the difference in the amount of electricity flowing into the circuit to that flowing out, it will not reset.
When power outlets will be located near water or near the ground, the Electrical Building code recommends installing GFCI power outlets. This would include any power outlets in your home that are closer than 1.5 metres from your sink, and outdoor power outlets that are located within 2.5 metres of the ground or next to a water source such as a swimming pool or outdoor tap.
Consider having GFCI power outlets installed in any or all of the following locations in your home:
Underwater Pool Lighting
Wet Bar Sinks
Electrical Code Requirements for GFCI
The CEC & NEC Code Requirements for GFCIs are aimed at providing protection to anyone who plugs into an electrical system. As per the CEC & NEC Code, the installation of GFCIs is a must in following areas:• 210.8(A) Dwelling Units