Is there a difference between Earthing Switch and Earthing Knife Switch?

Zhejiang SanGao Electric Co., Ltd., a pioneer in China’s power transmission and distribution sector, specializes in high-voltage solutions with integrated R&D, design, and manufacturing. Our earthing switches are engineered to match the dielectric insulation and fault-current capacity of associated disconnectors while ensuring safety in substations and transmission lines. This article clarifies the technical distinctions between earthing switches and earthing knife switches, highlighting SanGao’s industry-leading specifications.

Core Differences Explained

Earthing Switch: A robust system for grounding de-energized circuits, designed to handle electrostatic/electromagnetic induction currents. Typically interlocked with disconnectors to prevent live operation.

Earthing Knife Switch: A subtype emphasizing a visible blade mechanism. Focuses on manual operation for localized grounding, common in lower-voltage applications.

Key Functional Contrasts

SanGao Earthing Switch Product Specifications

Performance Parameters

Dielectric Strength: 230 kV power frequency withstand voltage (1 min)

Short-Time Current: 63 kA for 3 seconds

Inductive Current Switching: 2.5 kA (electromagnetic), 1.25 kA (electrostatic)

Mechanical Life: 10,000 operations

Ambient Suitability: -40°C to +55°C; 95% humidity

Design Advantages

Interlock System: Prevents closure on live circuits via mechanical/electrical safeguards.

Modular Construction: Compatible with disconnectors for unified substation layouts.

Corrosion Resistance: Epoxy-coated blades + stainless steel rods.

Line-Switching Capability: Isolates induced currents in parallel transmission lines.