Circuit-Breaker Failure Protection 3+1n Molded Case Circuit Breaker

3P breakers control three live wires (L1, L2, L3) for three-phase three-wire circuits, suitable for balanced loads like motors. 4P breakers add a neutral wire, suitable for three-phase four-wire systems, allowing simultaneous cutoff of phase and neutral wires to prevent abnormal neutral current.

1. Strictly connect three-phase live wires according to L1, L2, L3 marks to ensure correct phase sequence and prevent motor reversal. 2. Use copper wires or bars with cross-sectional areas matching the rated current to ensure good contact and avoid heating from excessive resistance.

Common reasons include: 1. Tripping mechanism failure, such as worn or stuck springs/locks in one pole. 2. Poor contact of contacts due to oxidation, ablation, or loose wiring in a specific phase, causing abnormal current and inconsistent protection actions.

We conduct comprehensive tests including electrical performance testing, mechanical performance testing, appearance inspection, and temperature rise tests to ensure product quality meets standards.

We use carton, cardboard box, and wooden box packaging, all complying with international export standards, to ensure products are not damaged during transportation.