The Square D 400A MAIN BREAKER I-LINE PANELBOARD 208Y/120V 3Ø 4W 18 CIR 12-4915773B0 is a circuit protection device from Square D. It provides overcurrent protection, breaking the circuit automatically if current exceeds a safe level. Key specifications noted on this listing include 400A. It is commonly in control panels, switchgear, and machine electrical systems.
