Specification

and QOB Miniature Circuit Breakers

Special Application Circuit Breakers

07/2008

QO-HM and QOB-HM High Magnetic Circuit Breakers

QO-HM and QOB-HM high-magnetic circuit breakers are recommended for area lighting (such as

athletic fields, parking lots, and outdoor signs), when using lamps of inherent high inrush current,

individual dimmer applications or other applications where high inrush currents exceed standard

tripping conditions. These circuit breakers are available in one-pole 15 and 20 A ratings only. QO-HM

and QOB-HM circuit breakers are physically interchangeable with standard QO and QOB circuit

breakers and accommodate the complete range of QO accessories.

QO-HM and QOB-HM circuit breakers are manufactured with the magnetic trip point calibrated at a

much higher level than standard QO and QOB circuit beakers, as shown in Table 3.

QO-HID and QOB-HID High Intensity Discharge Circuit Breakers

QO-HID and QOB-HID circuit breakers are for use in high intensity discharge (HID) lighting systems,

such as systems using mercury vapor, metal halide or high-pressure sodium lighting units. These

circuit breakers are designed to handle the high inductive loads, harmonic currents and cycling which

are inherent in HID lighting systems. QO-HID and QOB-HID circuit breakers are physically

interchangeable with standard QO circuit breakers and accommodate the complete range of QO

accessories.

QO-HID and QOB-HID circuit breakers are manufactured with larger contacts than standard QO and

QOB circuit breakers to allow switching of high inductive loads. They also have magnetic

characteristics similar to QO-HM and QOB-HM high-magnetic circuit breakers to allow the circuit

breaker to hold in against the high starting inrush currents which are typical in HID lighting systems.

QO and QOB Miniature Switches

Miniature switches are intended for use as disconnecting devices only. They provide no overcurrent

protection. QO and QOB switches are UL Certified for use on circuits capable of delivering not more

than 10 kA when protected by an equivalent rated circuit breaker or fuse. These switches are available

in 60 and 100 A rating.

QO and QOB switches are available with auxiliary switches only. (Shunt trip and bell alarm electrical

accessories are not available on QO and QOB miniature switches.) QO and QOB switches are

available with the complete range of handle accessories.

QOK and QOBK Key-Operated Circuit Breakers

Key-operated QOK and QOBK circuit breakers provide an alternative means for turning a circuit

breaker ON or OFF, as well as for resetting a tripped circuit breaker. The circuit breaker is turned on,

off or reset with a special key included with the circuit breaker. Key-operated circuit breakers are

available in one-pole construction only and can be mounted in any one-pole space which will accept a

standard QO circuit breaker. These circuit breakers are available in 10–30 A ratings, with interrupting

ratings of 10 kA at 120 Vac.

Replacement keys are available separately. Factory-installed or field-installable accessories are not

available on key-operated circuit breakers.

Table 3: QO-HM and QOB-HM Circuit Breaker Magnetic Hold Levels

Continuous Current Rating Maximum Full Cycle Magnetic Hold Level

15 A 315–525 A

20 A 322–537 A

07303099

1P QOK

Circuit Breaker