3 Pole Fuse Switch Disconnector 690V Knife Type

The ZHENGRONG HR6 knife-type fuse switch disconnector is a classic open-type switch-disconnector widely used in low-voltage power distribution. It combines two functions in one device: the knife-switch mechanism enables manual make/break of the circuit, while the integrated fuses provide short-circuit and overload protection — eliminating the need for a separate fuse holder.

The unit is a 3-pole design for three-phase systems, with six terminals (one incoming and one outgoing per phase) for easy and secure wiring. It is rated for operational voltage up to 660V at 50Hz, covering standard industrial and commercial supply networks.

Design & Operation

The switch is operated by a handle on top of the unit, allowing frequent or infrequent manual switching of the circuit. When opened, the knife contacts create a clear visible break — a key safety feature that guarantees isolation during maintenance and prevents accidental re-energization.

The internal contacts are silver-plated copper for low contact resistance and stable conductivity, ensuring reliable performance and low temperature rise even under continuous load.

Construction & InstallationThe 

housing is molded from light-grey flame-retardant engineering plastic with high mechanical strength and insulation performance. The translucent blue cover allows inspection of contact and fuse status without opening the unit. The base is equipped with mounting holes for screw fixing directly onto the mounting plate of distribution cabinets or control boxes.

Features

Knife switch + fuse protection in one unit — circuit switching, isolation and short-circuit protection combined, saving space and installation cost.

Clear visible break — open-type knife contacts provide an obvious disconnection point, ensuring maintenance safety.

3-pole three-phase design — simultaneous protection of all three phases with 6 terminals (in/out per phase) for easy wiring.

Silver-plated copper contacts — low contact resistance, low temperature rise and stable conductivity for long service life.

Translucent blue inspection cover — contact and fuse status visible at a glance without opening the unit.

Flame-retardant housing — high-strength engineering plastic with excellent insulation, impact and heat resistance.

Simple screw mounting — base mounting holes allow fast fixing on cabinet mounting plates.

Manual operation with visible indication — handle design supports frequent or infrequent switching with clear status indication.

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

Low-voltage distribution cabinets and control boxes

Main switch or branch-circuit switch in industrial distribution systems

Motor branch protection and isolation

Commercial and industrial power distribution

Power supply isolation for machinery and production equipment

Maintenance isolation points requiring visible break

Panel builders, electrical contractors and plant maintenance teams