Square D FH36090 Molded Case Circuit Breaker

This breaker is designed exclusively for use in Square D I-Line panelboards and switchboards. It utilizes a plug-on line connection that mounts directly to the internal bus system.

Both are legacy F-frame molded case circuit breakers with identical physical dimensions, but the FH series features a higher interrupting capacity. For example, the FH36090 is rated for 25kA at 480VAC, whereas the equivalent FA breaker is rated for 18kA at 480VAC.

The FH36090 is a legacy F-frame breaker that has been phased out by Schneider Electric. For modern upgrades or replacements in I-Line panels, it is typically replaced by the newer PowerPact B-frame or H-frame circuit breakers.

The breaker features plug-on phase connections on the line side that snap directly onto the I-Line panelboard bus. A retaining screw secures the breaker to the backpan, while the load side utilizes standard mechanical lugs for wire connections.

The standard load-side lugs on this 90A breaker accept copper or aluminum wire ranging from 14 AWG to 1/0 AWG. Ensure proper torque specifications are followed during installation to prevent thermal issues.

Yes, this thermal-magnetic breaker is rated for use in DC applications. It has a maximum voltage rating of 250VDC with an interrupting capacity of 10kA, making it suitable for specific industrial DC control circuits.

LI indicates that the thermal-magnetic trip unit provides Long-Time (L) protection for sustained overloads and Instantaneous (I) protection for short circuits. Both the thermal and magnetic trip points are factory fixed on this model and cannot be adjusted in the field.

Installation should only be performed by a qualified electrician. Ensure the panelboard is fully de-energized, verify power is off using a properly rated voltage tester, and follow all appropriate lockout/tagout (LOTO) procedures before seating the breaker onto the bus.