Panel-mounted motor protection with phase loss coverage
The GV4PE50B is a 50 A motor circuit breaker from the TeSys Deca range, built for three-phase motor protection. It combines a thermal-magnetic electronic trip with an 850 A magnetic short-circuit pickup and phase failure sensitivity per IEC 60947-4-1 — that means it will drop the load if one phase goes missing, not just overcurrent. The trip unit is electronic on top of the thermal-magnetic core, not just a bimetallic — you get tighter protection curves and better repeatability than a plain thermal breaker. At 50 A line rating, it covers motors from 11 kW at 400 V up to 45 kW at 690 V. Check your nameplate FLA against the 50 A fixed setting; this breaker is not adjustable.
Durability and environment
Mechanical durability is 40,000 cycles, electrical durability is 20,000 cycles at full load (AC-3, 440 V, In/2) and 10,000 cycles at rated current. That's a solid service life for a motor-only breaker that doesn't see daily switching. Fire resistance tested to 960 °C (IEC 60695-2-11) — important if the panel must meet thermal propagation requirements.
Termination and layout
Terminals are EverLink BTR screw type — the ones that clamp with a consistent torque regardless of wire stiffness. Top terminals accept 1.5–70 mm² solid or 1.5–50 mm² flexible; bottom terminals go up to 95 mm² solid and 70 mm² flexible. That's generous for a 50 A breaker, giving you headroom for paralleled feeds or larger cable if the run is long. Tightening torque is 9 N·m (79.7 lbf·in) for the main terminals, 5 N·m (44.3 lbf·in) for the smaller control wires. Stick to those numbers — under-torquing kills the short-circuit rating, over-torquing strips the threads. The breaker occupies a 3.2 in wide, 6.1 in tall, 4.6 in deep footprint. Panel-mount only; no DIN rail base. Mount in any position, but allow clearance for the toggle handle travel. Power dissipation is 4.6 W per pole at full load.
Breaking capacity is 50 kA at 240 V AC (IEC), 25 kA at 415 V, and 10 kA at 500 V. Under UL 60947, it is 35 kA at 240 V and 18 kA at 480Y/277 V. The utilisation category is A (IEC 60947-2) and AC-3 (IEC 60947-4-1), meaning it's designed for switching motors and has no deliberate time delay on short-circuit — it trips magnetically at 850 A (17x In). That's fast enough to protect the motor cable and contactor from let-through energy.