HR18 Series Fuse Isolating Switch Manufacturer

HR18 Fuse Switch Disconnectors

The HR18 series fuse isolating switches are designed for AC 50/60Hz power distribution networks with rated voltages up to 660V. These units provide integrated load-breaking, circuit isolation, and short-circuit protection, serving as critical components in low-voltage switchgear, cable distribution boxes, and industrial motor control centers (MCC).

Description

Scope of Application

The heavy-duty HR18 series fuse isolating switches are professionally designed and optimized for low-voltage AC 50/60Hz power distribution networks with rated operational voltages up to 660V. These rugged units provide highly integrated load-breaking capabilities, secure circuit isolation, and robust short-circuit protection, serving as critical components in industrial low-voltage switchgear, outdoor cable power distribution boxes, and specialized motor control centers (MCC). By accommodating various fuse link sizes, they ensure precise overcurrent safeguarding across high-demand electrical grids.

In commercial and industrial sectors, the HR18 fuse isolating switch is specifically tailored for high-reliability environments such as mission-critical data centers, advanced healthcare facilities, and heavy manufacturing plants. It is particularly effective in modern renewable energy power distribution systems, specifically within photovoltaic combiner boxes and wind power distribution frames where long-term thermal stability and minimal power loss are paramount. The specialized housing materials offer superior heat dissipation, preventing degradation during continuous, full-load operations.

A primary safety feature of the HR18 fuse isolating switch is its prominent, highly intuitive visible physical isolation gap, which effectively ensures total physical disconnection from the live busbar system during routine onsite maintenance to completely prevent hazardous arc-flash incidents. Interlocking mechanisms prevent accidental opening under load, protecting maintenance personnel from severe injury. Furthermore, its versatile and compact architecture seamlessly supports both main incoming supply configuration and downstream feeder short-circuit protection across diverse international power distribution systems. This adaptable design facilitates rapid DIN-rail or panel mounting, maximizing panel space while dramatically reducing installation time and long-term operational costs.

Normal working conditions

Ambient Temperature: Operations are rated for -5°C to +40°C, with a 24-hour average not exceeding +35°C. The unit maintains mechanical integrity during storage down to -25°C.

Altitude: Standard installation is rated up to 2,000 meters; de-rating factors apply for higher altitudes to account for reduced dielectric air strength.

Atmospheric Stability: Relative humidity should not exceed 50% at a peak temperature of +40°C. At lower temperatures (e.g., +20°C), humidity up to 90% is permissible. The housing design incorporates ventilation clearance to manage potential condensation.

Environmental Class: Rated for Pollution Degree 3, the fuse isolating switch is resistant to conductive dust and non-corrosive vapors in heavy industrial zones, ensuring reliable short-circuit protection.

Structural features

The HR18 series stands out for its modular, front-operated architecture which prioritizes operational safety and space efficiency in the power distribution cabinet. The fuse isolating switch body is constructed from high-strength, flame-retardant materials, featuring a transparent protective cover that allows for instant visual verification of the fuse links.

Internally, the fuse isolating switch utilizes reinforced silver-plated copper contacts and an advanced arc-extinguishing system to minimize power loss and ensure a high breaking capacity for ultimate short-circuit protection. The design is highly versatile, offering both fixed and hanging (busbar-mounted) installation options to suit different busbar system and cabinet layouts. Furthermore, the unit can be equipped with an optional electronic fusing signal module, enabling remote monitoring of fuse status—a critical feature for modern smart power distribution grids. Its compact, vertical configuration is specifically optimized for high-density busbar systems, significantly reducing the footprint within the power distribution board.

Product Model and Its Meaning
HR18 Fuse Switch Disconnectors

Technical Parameters

The HR18 range is a comprehensive series catering to diverse industrial requirements, featuring rated heating currents of 160A, 250A, 400A, and 630A.

Voltage & Dielectric Strength: Designed for rated operating voltages (Ue) of AC 400V and 660V, the series boasts a rated insulation voltage (Ui) of 800V and a rated impulse withstand voltage (Uimp) of 8kV. This ensures the switch can withstand significant transient overvoltages common in industrial power grids.

Load Switching Capability: Compliant with the AC-23B utilization category, the HR18 is capable of switching highly inductive motor loads or mixed loads with frequent operation. Its mechanical durability exceeds 3,000 cycles, while the electrical life under full load remains industry-leading.

Short-Circuit Coordination: When paired with high-quality HRC fuse links, the HR18 can handle prospective short-circuit currents up to 100kA at 400V. This high level of "back-up protection" ensures that the switch remains functional even after clearing a major fault.

Global Compliance: Every unit is manufactured and tested in strict accordance with the IEC 60947-3 and GB/T 14048.3 standards. The design also takes into account electromagnetic compatibility (EMC), ensuring that the switch does not interfere with sensitive electronic control systems nearby.

External appearance and installation dimensions

Model	External Dimension and Installation Dimension							Fuse-link
Model	A	B	C	D	E	F	G	Fuse-link
HR18-160	184	105	88	160	43	73	25	NT00
HR18-250	268	184	116	230	66	115	50	NT1
HR18-400	285	210	129	256	81	140	50	NT2
HR18-630	328	250	138	315	86	150	50	NT3