"Back Feeding" Of Moulded Case Circuit Breakers And Panelboards
Bulletin 14-5-0
Rule 14-418 (page 84)
The following does not apply to a panelboard used in service entrance applications as Canadian Standards
Association Standard C22.2 No. 86 requires a barriered main disconnecting device.
It is a common field practice to wire an individually mounted circuit breaker with the top as line side and the bottom
as load side. In an effort to reduce installation cost as an alternative when it is not otherwise practicable to provide a
main disconnect there has been an increase in the practice of "back-feeding" circuit breakers, i.e., terminating the line
conductors on the "Load" side of the breaker and the load conductors on the "Line" side.
The following are
guidelines to be followed before approving such an installation:
1. The circuit breaker must be certified and must not have any marking identifying line and/or load terminals,
e.g., most GFCI circuit breakers must not be back-fed as there are definite line and load terminals.
2. The circuit breaker must be of the non-interchangeable thermal magnetic trip or factory sealed
interchangeable trip type or constructed with a solid state trip circuit.
3. The breaker must be permanently marked to identify the actual line and load connections and the circuit
directory card marked in a permanent and legible manner as the main breaker. Interchangeable trip circuit
breakers must be factory sealed against inadvertent cover removal. A suitable number of cover screws
epoxied over, or other similar method of ensuring against inadvertent cover removal, are acceptable.
As an extension of this, a branch circuit breaker in a panelboard is often back-fed and thus utilized as the main
breaker for the panel board. This practice may be accepted provided that, in addition to the above requirements, the
circuit breaker is also identified on the panelboard trim, breaker and on the circuit directory card as the main breaker.
The preceding does not apply to a panelboard used in service entrance applications as Canadian Standards
Association Standard C22.2 No. 86 requires a barriered main disconnecting device.
Tony Moscioni
Electrical Inspector
© Electrical Safety Authority - 2002
