Protection Type Reference Chart

Reference Chart

Protection Type

Breaker Type


Thermal-Magnetic Common Breaker A standard thermal-magnetic breaker protects a circuit from an overcurrent failure. Overcurrent failures can occur when the total amp draw of all devices currently running on a circuit is more than the circuit can safely supply.
Thermal-Magnetic + Ground Fault Ground Fault Interrupter (GFI) / Ground Fault Circuit Interrupter (GFCI) A ground fault circuit interrupter adds protection against ground faults to overcurrent protection. In order to safely control the flow of electricity the path to ground needs to be predictable. A GFCI breaker detects when the path becomes unpredictable by a variance of 5mA or greater.
Thermal-Magnetic + Combination Arc Fault Combination Arc Fault Interrupter (CAFI) A combination arc fault interrupter adds protection against parallel and series arc faults to overcurrent protection. Arc faults occur when the hot lead of a circuit either arcs to another hot lead (parallel) or arcs across an air gap in the same lead (series). 
Thermal-Magnetic + Ground Fault + Combination Arc Fault Dual-Function (DF) A dual function breaker combines overcurrent, ground fault and combination arc fault protection in one device.

Other Designations Found on Circuit Breakers

Switching Duty Switching Duty Rated (SWD) Switching Duty Rated breakers designed to be used to regularly switch a circuit on/off. Only single pole, 277VAC or below, 20A or 15A breaker can be designated as switching duty rated. These breakers are most commonly used in lighting circuits.
Heating, Air-conditioning, Refrigeration HACR Listed HACR listed breakers are confirmed by an independent testing laboratory to be suitable for HACR applications. Even though these breakers are HACR listed this is usually not their most common application. HACR listed breakers are not prohibited from other applications.