Abb mb331wb Main Breaker Kit 400A 3-pole 65kaic

Product Description

The ABB mb331wb is a main breaker kit rated for 400 amps at 240 volts AC and 208Y/120 volts AC, designed for use with AQU1 and AQU3 panelboards. The kit includes a breaker and provides a 3-pole main disconnect solution with an interrupting rating of 65 kAIC. It serves as the primary overcurrent protection device at the service entrance of a panelboard, isolating all downstream branch circuits when tripped or manually switched off. Licensed electricians install this component as part of new panelboard builds or service upgrades where a main breaker is required by code.

This kit is suited for commercial and light industrial electrical distribution applications where a 400-amp, 3-pole main breaker is required. It is compatible with AQU1 and AQU3 series panelboards and supports both 208Y/120-volt three-phase and 240-volt AC systems. It is appropriate for use in multi-tenant commercial buildings, industrial facilities, and other installations requiring high-capacity service entrance protection.

Key Features

• 400-amp continuous current rating for high-capacity service entrance applications
• 3-pole configuration supports three-phase distribution systems
• Dual voltage rating: 240 volts AC and 208Y/120 volts AC
• 65 kAIC interrupting rating for use in high fault-current environments
• Includes breaker — complete kit ready for panelboard installation
• Designed for AQU1 and AQU3 series panelboards

Compatibility

Designed for use with ABB AQU1 and AQU3 series panelboards operating at 240 volts AC or 208Y/120 volts AC.

Installation Notes

Installation must be performed by a licensed electrician in accordance with the National Electrical Code (NEC) and all applicable local codes. De-energize and lock out the utility service before beginning any panelboard work. Verify the panelboard bus rating and service entrance conductors are rated to match the 400-amp breaker before installation. Do not exceed the 65 kAIC interrupting rating of the breaker for the available fault current at the point of installation.