Square D 9421LT1 Circuit Breaker Operating Mechanism

Product Description

The SQUARE D 9421LT1 is a replacement operating mechanism designed for 800-amp molded-case circuit breakers. The operating mechanism is the mechanical assembly responsible for opening and closing the breaker contacts, providing manual operation and trip-reset capability within the breaker frame. This component is used in commercial and industrial electrical distribution systems where reliable switching and protection are critical. Installation is performed by licensed electricians during scheduled maintenance or breaker refurbishment work.

This operating mechanism is suited for use in commercial and industrial panel and switchboard applications where MEL, MXL, MAL, and MHL series molded-case circuit breakers are installed. It is a direct-fit replacement intended to restore or maintain the mechanical switching function of existing breaker frames without requiring full breaker replacement.

Key Features

• Rated for use with 800-amp molded-case circuit breaker frames
• Compatible with MEL, MXL, MAL, and MHL series breakers
• OEM-style replacement restores full mechanical operation of the breaker
• Supports manual open and close operation as well as trip-reset functionality
• Sold individually as a single-unit package

Compatibility

Designed for use with SQUARE D MEL, MXL, MAL, and MHL series molded-case circuit breakers.

Installation Notes

Installation should be performed by a qualified, licensed electrician in accordance with the National Electrical Code (NEC) and all applicable local codes. The circuit must be fully de-energized and locked out or tagged out before removing or installing any breaker component. Verify that the replacement mechanism is confirmed compatible with the specific breaker frame before beginning disassembly. Follow the manufacturer's service documentation for proper assembly sequence and mechanical engagement verification.