Circuit breaker Legrand 403402, 3-pole, 16 A, 400 V

Three-pole circuit breaker Legrand 403402 rated for 16 A and 400 V. Designed to protect three-phase electrical circuits from overloads and short circuits, this compact modular device is intended for installation in distribution boards in residential, commercial or light industrial electrical systems. The breaker interrupts fault currents to protect wiring and connected equipment while enabling straightforward mounting and connection within standard DIN-rail enclosures.

Advantages

The three-pole configuration ensures simultaneous disconnection of all phases for balanced protection of three-phase loads. A 16 A rated trip threshold and 400 V insulation rating match common low-voltage three-phase installations. The modular form factor saves panel space and facilitates combination with adjacent protective and switching devices. Construction and materials provide consistent thermal and magnetic tripping characteristics for reliable operation under overload and short-circuit conditions.

Suitable for

• Protection of three-phase supply lines for motors and pumps
• Distribution boards in small commercial premises
• Residential three-phase panels and apartment buildings
• Light industrial control circuits and branch circuits

Key specifications

• Poles: 3-pole for simultaneous phase disconnection
• Current rating: 16 A
• Rated voltage: 400 V (AC)
• Type: Thermal-magnetic circuit breaker (overload and short-circuit protection)
• Mounting: DIN-rail modular format for distribution boards
• Connection: Screw terminals for phase conductors and neutral/earth as required
• Application environment: Indoor electrical distribution panels

How to use

Install the breaker on a compatible DIN-rail inside the distribution board and secure it according to the enclosure manufacturer’s instructions. Connect the incoming three-phase supply conductors to the line terminals and the load conductors to the load terminals, observing correct phase sequence and tightening torque for the screw terminals. Ensure the panel is de-energized before installation or maintenance. After wiring, restore power and verify correct operation by switching the breaker on and off and confirming protection behavior under expected load conditions.

Usage recommendations

Choose the breaker as part of a coordinated protection scheme: verify conductor sizing, upstream and downstream device characteristics, and short-circuit current levels in the installation. Periodically inspect terminal tightness and signs of overheating, and replace the device if it shows mechanical damage or degraded performance.