40A B Curve 30mA A Type RCBO (NB3LEG-B40)

The Chint NB3LEG‑B40 40A B Curve 30mA A Type RCBO combines critical electrical protection and compact design in one essential safety device. Designed for use in single-phase circuits, this RCBO protects your wiring and appliances by detecting both overloads and earth leakage faults. Built to meet BS EN safety standards, it reliably safeguards electrical installations in homes, workshops, offices, and light commercial settings.

Engineered for modern electrical systems, this RCBO integrates over-current protection and residual current detection into a single module that fits neatly on a standard DIN rail. With a B Curve characteristic, it responds quickly to moderate surge currents without nuisance trips, making it suitable for general circuits such as lighting, sockets, and everyday appliances. Its Type A residual current detection senses both alternating and pulsating DC leakage, offering broader protection for circuits that include electronic loads such as LED drivers, appliances, or chargers.

The device has a rated current of 40 amps and a residual current trip threshold of 30mA, ideal for personal protection against electric shock and fire risk. The robust 6kA short-circuit breaking capacity ensures reliable disconnection during faults, helping prevent damage to equipment and wiring. Compact and lightweight, the RCBO mounts easily on a 35 mm DIN rail to make installation fast and straightforward.

Built for durability and performance, this unit includes a clear contact position indicator that shows at a glance whether the circuit is closed or open. Whether you are upgrading existing protection or specifying new installations, the NB3LEG‑B40 is a dependable choice for enhanced circuit safety and compliance.

40A B Curve 30mA A Type RCBO (NB3LEG-B40) – Data Sheet