What this neutral disconnector does in the panel
The ABB 2CCS400900R0011 is a neutral disconnector rated for 400 V, with a 9 mm width per pole. It sits in the Circuit Breaker Accessories family and is used alongside miniature circuit breakers or residual current devices to provide a means of isolating the neutral conductor during maintenance or testing — a standard requirement in distribution boards where the neutral must be switched, not just the phases.
Why the 9 mm width matters for panel layout
At 9 mm wide, this disconnector takes up one standard modular DIN-rail slot. That means it fits into the same enclosure footprint as a single-pole MCB, so you can add neutral isolation without widening the panel or re-spacing the existing devices. For a 24-way distribution board, every 9 mm slot counts — this part keeps the neutral switching function from eating into phase circuit capacity.