3 Pole Fuse Switch Disconnector 400A 690V

The ZHENGRONG HR17-400 fuse switch disconnector is a heavy-duty unit designed for high-current low-voltage three-phase distribution. It combines the functions of a load switch, isolating switch and short-circuit protection in one device, protecting cables, motors and other electrical equipment from overload and short-circuit damage.The 3-pole design protects all three phases simultaneously, with three independent fuse positions and contact assemblies visible through the front window. Rated 400A at 660/690V AC, 50/60Hz, it is suited for main circuits and heavy branch circuits in industrial plants and commercial buildings.

Design & Operation

A wide lifting-handle on top provides comfortable manual operation for make/break switching. The distinctive three-arc translucent blue window allows operators to inspect the status of all three poles at a glance without opening the unit — speeding up routine inspection and blown-fuse detection.

When opened, the disconnector forms a clear visible break, ensuring safe isolation during maintenance and emergency shutdown. The internal fuse bases and contact assemblies are built for reliable high-current performance.

The housing is molded from off-white/light-grey flame-retardant engineering plastic (high-strength polyamide/nylon or reinforced grade) offering excellent insulation, heat resistance and mechanical strength. The modular, compact design integrates easily into distribution panels.

Installation is base-fixed: mounting holes on both sides of the base allow secure fixing onto busbars or the cabinet mounting plate — suitable for high-current applications in power distribution cabinets.

High-current capacity

● — rated 400A for main circuits and heavy branch circuits.

Switch + isolation + fuse protection in one unit

● — load switching, isolation and short-circuit protection combined, saving space and cost.

3-pole three-phase protection

● — simultaneous protection of all three phases.

Triple-arc blue window

● — fuse status of all three poles visible at a glance without opening the unit.

Wide lifting handle

● — comfortable, reliable manual make/break operation.

Visible break isolation

● — clear disconnection point when open, ensuring maintenance safety.

Flame-retardant housing

● — high-strength engineering plastic with excellent insulation, impact and heat resistance.

Robust base fixing

● — mounting holes for secure installation on busbars or mounting plates.

50/60Hz compatibility

● — suitable for global supply networks.

Quality certified

● — ISO9000, CCC and CE certified for domestic and export markets.

Application

● Factory power distribution boxes and control cabinets

● Main and branch circuits in commercial building distribution systems

● Protection of cables, motors and electrical equipment from overload and short-circuit

● High-current low-voltage distribution systems

● Motor control centers 

● Maintenance isolation with visible break

● Panel builders, electrical contractors and plant maintenance teams