Square D NC36900 Molded Case Circuit Breaker

The NC36900 is an N-frame breaker with an I-Line plug-in connection. It is exclusively designed for Square D I-Line panelboards and switchboards that can accommodate its physical size and mounting requirements. It cannot be installed in standard QO or NQ panels.

This breaker utilizes an I-Line style plug-in connection. The line side features jaws that push directly onto the panelboard bus stack, while the load side is secured to the panel backpan with mounting screws.

The factory lugs accept up to three conductors per phase, ranging from 3/0 AWG to 500 kcmil. They are rated for both aluminum and copper wire. Always apply the manufacturer specified torque during termination.

While the thermal overload protection is fixed at 900A, the magnetic trip is adjustable. This allows electricians to fine-tune the instantaneous short-circuit response to coordinate with other breakers in the system and prevent nuisance tripping from motor inrush currents.

The 100kAIC rating specifies the maximum fault current the breaker can safely clear at 480VAC without sustaining internal damage. This high interrupting capacity makes it suitable for industrial facilities with substantial available short-circuit currents.

No. As a standard 3-pole I-Line circuit breaker, the NC36900 is supplied with an ABC phase jaw configuration. It connects directly to all three phases of the panelboard bus stack simultaneously, requiring no special phase designation when ordering.

The NC36900 is a legacy N-frame molded case circuit breaker. While it remains widely used and supported for existing I-Line installations, Square D typically utilizes the PowerPact P-frame series for new panelboard designs in this amperage range.

Always de-energize the panelboard or switchboard before installing or removing the NC36900. Verify that power is off using a properly rated voltage sensing device, and ensure the breaker toggle is in the OFF position before engaging the I-Line jaws with the bus stack.