480Y/277V Main Breaker Kit

The ABB MB423 is a main breaker kit designed for 480Y/277V lighting and distribution panelboards. It enables installation of a main disconnect or sub-feed breaker in A-Series II and ReliaGear panelboard systems.

This model is specifically designed for use with TEY frame breakers and is commonly applied in higher voltage commercial and industrial lighting systems.

Key Features

• 480Y/277V, 3-phase configuration
• Designed for TEY frame bolt-on breakers
• Typical amp range: 100–125A
• 14 kAIC interrupt rating
• Compatible with A-Series II and ReliaGear panelboards
• Includes mounting hardware and lugs
• Breaker sold separately

Typical Applications

Ideal for commercial lighting panelboards, industrial distribution systems, and 480/277V building infrastructure. Commonly used for lighting loads, HVAC systems, and panelboard main disconnect applications.

Construction Details

Includes all necessary components for secure installation, including mounting brackets, bus connections, and load-side lugs. Designed for precise fitment with TEY breakers and compatible panel interiors.

Important Notes

Not interchangeable with 208/120V breaker kits such as MB612 or MB613.

Verify fault current rating and panel compatibility before installation.