Where fiber optic communication devices are fitted, these should not be viewed directly. Optical power meters should be used to determine the operation or signal level of the device.
QO-EPD and QOB-EPD circuit breakers are one- and two-pole thermal-magnetic circuit breakers with
integral equipment ground-fault protection. These circuit breakers are rated for use on 120/240 Vac
and 120/208 Vac electrical systems to provide overcurrent protection, short-circuit protections and
equipment ground-fault protection.
EPD circuit breakers are built in accordance with UL Standard 489. QO-EPD and QOB-EPD circuit
breakers are not designed to protect people from the hazards of electrical shock. The ground-fault
protection level is 30 milliamperes to protect electrical equipment such as heat trace tape.
QO-EPD and QOB-EPD circuit breakers include a self-contained means of testing the ground-fault
circuitry. If the circuit breaker is connected correctly, with the pigtail connected to the neutral assembly
in the load center or panelboard, pressing the test button will trip the circuit breaker and show a trip
indication. EPD circuit breakers must be operational at 85% of the rated voltage.
EPD circuit breakers provide the same branch circuit protection as standard QO and QOB circuit
breakers. They are longer than standard QO circuit breakers, and thus require more gutter space. All
QO electrical accessories except shunt trip and all QO mechanical accessories are available for QOEPD and QOB-EPD circuit breakers.
QO-SWN and QOB-SWN Switch Neutral Circuit Breakers
The QO-SWN and QOB-SWN switch neutral circuit breakers are designed to protect gas pump
assemblies.These circuit breakers have provisions for switching the grounded conductor as outlined in
the National Electrical Code.
The QO-SWN and QOB-SWN circuit breakers are designed to simultaneously open all grounded and
ungrounded conductors. All branch circuit wiring is terminated on the load side of the circuit breaker.
The panel neutral connection is made using the pigtail lead built into the circuit breaker. Two-wire
circuit breakers require two pole spaces; three-wire circuit breaker require three pole spaces.
QO-SWN and QOB-SWN circuit breakers are available with the complete range of QO accessories.
QOT Tandem Circuit Breakers
QOT tandem circuit breakers are manufactured so two one-pole, thermal-magnetic circuit breakers
occupy only one QO pole space. They are used in applications where circuit loading is light and/or
noncontinuous, as in residential applications. QOT circuit breakers are available in 15/15 ampere,
15/20 ampere and 20/20 ampere construction.
QOT circuit breakers have a mounting cam to limit their installation in QO load centers to only those
positions having a mounting rail slot. This physically limits the total number of circuit beakers permitted
in the panelboard for safe operation.
Each one-pole QOT circuit breaker provides individual switching and tripping action. Individual trip,
two-pole circuit with common switching may be assembled by using a handle tie (kit QOTHT) between
two adjacent QOT circuit breakers.
