Square D 9421LR1 400 Amp Circuit Breaker Operating Mechanism

Product Description

The SQUARE D 9421LR1 is a 400-amp circuit breaker operating mechanism designed for use with Q4L, LAL, and LHL series molded-case circuit breakers. This accessory provides the mechanical means to manually operate, trip, or reset a large-frame breaker from outside an enclosure or switchboard panel. It is built for high-amperage distribution applications where direct hand operation of the breaker is not practical or safe. Licensed electricians and panel technicians install this component as part of a complete breaker assembly. The mechanism weighs 5.87 pounds and measures 11.8 inches in length, 5.5 inches in width, and 8.3 inches in height.

This operating mechanism is suited for commercial and industrial electrical distribution systems where Q4L, LAL, or LHL frame circuit breakers are installed in switchboards, motor control centers, or large panelboards. It allows the breaker to be operated without direct contact with the breaker handle, a common requirement in high-amperage distribution gear. Typical applications include main service equipment, feeder circuits, and industrial power distribution panels where 400-amp overcurrent protection is required.

Key Features

• Rated for use with 400-amp Q4L, LAL, and LHL series circuit breakers
• Provides remote manual operation and reset of the breaker assembly
• Compact form factor at 11.8 x 5.5 x 8.3 inches for switchboard integration
• Weighs 5.87 pounds for straightforward panel installation
• OEM accessory type ensures proper mechanical fit with supported breaker frames

Compatibility

Designed for use with SQUARE D Q4L, LAL, and LHL series molded-case circuit breakers as specified by the manufacturer.

Installation Notes

Installation should be performed by a licensed electrician in accordance with NFPA 70 (NEC) requirements for service equipment and distribution panels. De-energize and lock out the affected circuit or main service before mounting or connecting the operating mechanism. Verify that the breaker frame series matches the supported types before installation. Follow the manufacturer's installation instructions for mechanical alignment and fastener engagement.