FN7-12DR Indoor 12kV 3-Phase High Voltage AC Load Break Switch with Fuse and Earthing Switch

High-Voltage Indoor Load Break Switch Series (FN18 & FN7)

1. Product Overview

Our high-voltage indoor load break switch series includes the FN18 and FN7-12DR types, designed for reliable performance in medium-voltage distribution systems. These switches are essential building blocks for metal-enclosed and pad-mounted switchgear applications, particularly in city network construction, high-rise buildings, and transformer protection.

2. FN18 Series: Advanced Arc-Extinguishing Technology

The FN18 series is a three-pole, air-insulated switch that combines two proven technologies: compressed-air and gas-produced arc extinguishing.

• Integrated Protection: When combined with a fuse, it combines the advantages of a load switch and a fuse to break load currents and short-circuit currents effectively.

• Robust Construction: Built with a heavy-duty steel frame, stand-off insulators, and a puffer-type arc extinguishing system.

• Standard Features: Includes blade-type interrupters with cast hinges and jaw connectors for high reliability and fast breaking speed.

• Optional Accessories: Available with motor operators, auxiliary switches, shunt trip devices, and mechanical interlocking systems.

3. FN7-12DR Series: Compact and Efficient

The FN7-12DR type is an indoor AC off-voltage load break switch applicable to 50Hz, 12kV three-phase power systems.

• Premium Materials: Adopts high-quality brand-new raw materials with full oblique seams.

• Short-Circuit Resilience: Equipped with a grounding switch capable of withstanding short-circuit currents.

• Enhanced Durability: Features a thickened stainless steel shell for superior protection.

4. Technical Specifications

5. Usage Environment Requirements

To ensure optimal performance and longevity, the switches must be operated within the following conditions:

• Ambient Temperature:

  • Maximum: +40°C.

  • 24-hour Average: +35°C.

  • Minimum: -15°C (according to “minus 5 indoor class”).

• Humidity:

  • Daily Average Relative Humidity: ≤ 95%.

  • Monthly Average: ≤ 90%.

• Atmospheric Pressure:

  • Daily Saturated Vapor Pressure: ≤ $2.2 \times 10^{-3}$ MPa.

  • Monthly Average: ≤ $1.8 \times 10^{-3}$ MPa.

• Altitude: Maximum site altitude is 1000m above sea level.