Proper Wire Sizing and Protection of the Circuit

Fuse A one time use device that protects the circuit from overloading. If the circuit is overloaded the fuse will “blow” (the filament in the fuse will melt in two) The size of fuse used will depend on the size of wire that is being used in the circuit

Circuit Breaker Device that is used to keep the circuit from becoming overloaded. Overloaded circuits become hot and can catch fire. Will “trip” if overloaded The size of breaker depends on the size wire that is being used on the circuit.

Wire Size and Breaker Size Wire SizeBreaker Size

Wire sizes AWG = American Wire Gauge – a standard for designating the size of electrical wire The larger the number, the smaller the diameter of the wire. The smaller number, the larger the diameter of the wire

House Wiring Most circuits in houses are either size 14 or 12. Larger appliances such as dryers and ranges use larger wire (10 or 8)

Wire Size Labeling NEC state that all electrical conductors have the following info stamped on the wire AWG Size Voltage Rating Insulation TypeTesting Agency Number of Conductors

Example of Commmon Wires  12/2  12/2 wg  12/3 wg  14/2  12/2 wg  14/3 wg