QO miniature circuit breakers and switches are available for surface-, flush-, or DIN rail mounted applications. QO miniature circuit breakers are used for overcurrent protection and switching on both ac and dc electrical systems. QO circuit breakers and switches measure 0.75 in. (19 mm) wide per pole. Two- and three-pole circuit breakers are both equipped with an internal crossbar for common tripping of all poles. Cases for QOU miniature circuit breakers and switches are constructed of a glass-reinforced insulating material that provides high dielectric strength. Current carrying components are isolated from the handle. The handle position indicates whether the circuit breaker is off, on or tripped.
Two-pole QO circuit breakers rated 120/240 Vac are UL Listed for use on 120/240 Vac single-phase, three-wire or 208Y/120 Vac three-phase, four-wire electrical systems. They cannot be used on 240 V delta systems. They can handle one #4-#2/0 AWG Cu or Al wire.
QO miniature circuit breakers are supplied with mounting brackets for both line and load side support. Mounting brackets are field installable and can be attached to the front or back of the circuit breaker molded case. All QO miniature circuit breakers also come equipped with slots in the molded case for DIN rail mounting. These miniature circuit breakers are designed for use with a standard 35 mm DIN mounting rail (DIN/EU 50 022, 0.30 x 1.38 in. [7.5 mm x 35 mm]).
2-pole construction