SIEMENS ECQML12 Mechanical Interlock Circuit Breaker

Siemens ECQML12 Mechanical Interlock

The Siemens ECQML12 is a mechanical interlock accessory designed for BQ series circuit breakers. It provides a physical barrier that prevents two adjacent breakers from being switched on simultaneously. This component is intended for electricians and facility managers who need to enforce safe changeover or load-shedding arrangements in residential or light-commercial panels. It fits single-pole devices and helps meet code requirements for interlocking.

Installation fits standard BQ breaker frames

The interlock snaps onto the toggle area of two neighbouring single-pole breakers, linking their movement mechanically. Most installers complete the job in minutes using only a screwdriver to secure the mounting hardware. The main issue arises when the panel interior is crowded; limited space between breakers or existing accessories can block the interlock from seating correctly. Verify that the adjacent poles are standard BQ models before starting.

Check that your panel uses Siemens BQ single-pole

The ECQML12 is built exclusively for that breaker family and will not fit other brands or frame sizes. Confirm you have exactly two adjacent single-pole positions available for the interlocked pair. Ensure the panel cover can close over the added height of the interlock assembly. No other electrical ratings or pole configurations are supported by this accessory.