Square D 9421LL1 400A Circuit Breaker Operating Mechanism

Product Description

The SQUARE D 9421LL1 is an operating mechanism accessory designed for 400-amp molded-case circuit breakers. It provides the mechanical linkage that allows external operation of the breaker, enabling the breaker to be opened or closed from outside an enclosure without direct manual contact with the breaker itself. This component is installed by licensed electricians during panel and switchgear assembly or retrofit work where remote or external breaker operation is required. Key attributes include a 400-amp rating and compatibility with specific SQUARE D breaker families. Packaged as a single unit, it is a direct replacement or field-add accessory for qualifying circuit breaker assemblies.

This operating mechanism is intended for use with SQUARE D Q4L, LAL, and LHL series molded-case circuit breakers in commercial and industrial electrical distribution applications. Typical installation scenarios include motor control centers, switchboards, and panelboards where safe external operation of a 400-amp breaker is required. It is suited for both new installation and retrofit applications where an existing breaker requires an operating mechanism added after initial installation.

Key Features

• Rated for 400-amp circuit breaker applications
• Accessory type: operating mechanism for external breaker actuation
• Compatible with Q4L, LAL, and LHL SQUARE D circuit breaker frames
• Packaged as a single unit for direct field installation
• Dimensions of 11.5 inches length, 5.5 inches width, and 8 inches height allow fitment in standard enclosure configurations

Compatibility

Designed for use with SQUARE D Q4L, LAL, and LHL series molded-case circuit breakers rated at 400 amps.

Installation Notes

Installation must be performed by a qualified electrician in accordance with the National Electrical Code (NEC) and all applicable local codes. The circuit must be fully de-energized and locked out per OSHA lockout/tagout procedures before installing or servicing any circuit breaker accessory. Verify breaker frame compatibility before mounting the mechanism. Consult the manufacturer installation instructions for proper attachment sequence and hardware requirements.