DNH51 DC Knife Switch 440v 690v PV System 125A PV Knife Switch GRL manufacture

Rated Operating Current Ie (A)：

32, 40, 63, 80, 100, 125

Rated Operating Voltage Ue (V)：

AC 400V/690V, DC 250V/440V

Rated Insulation Voltage Ui (V)：

800

Rated Impulse Withstand Voltage Uimp (V)：

Short-time Withstand Current (kA/s)：

Utilization Category ：

AC-20B, DC-PV0

Operation Mode：

Manual, Close

Mechanical Lifespan (times)：

10,000

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Description

DC Knife Switch Overview

The DNH51-125/4 DC Knife Switch by GRL Electric is a robust isolation switch designed for PV systems. It supports up to 690V AC (or 440V DC) and a rated impulse withstand voltage of 6kV. This switch ensures safe and reliable manual circuit switching and isolation in PV systems, offering enhanced operator protection by reducing the risk of electric shock during maintenance and operation.

This PV knife switch integrates seamlessly with other DC protection devices, such as the DNPVF DC Fuse Holder, PV Combiner Box, and RT18 PV Fuse Holder, providing comprehensive protection and circuit control for your PV installations.

What is the purpose of an isolation knife switch?

Isolating knife switches are mainly used in low-voltage complete sets of equipment. They are switch devices without arc extinguishing equipment. They are mainly used to disconnect the circuit of no-load current and isolate the power supply to ensure the safe maintenance of other electrical equipment.

DC Knife Switch Technical Parameters

Rated Operating Current Ie (A)	Rated Operating Voltage Ue (V)	Rated Insulation Voltage Ui (V)	Rated Insulation Voltage Ui (V)
32	AC 400V/690V, DC 250V/440V	800	4
40	AC 400V/690V, DC 250V/440V	800	4
63	AC 400V/690V, DC 250V/440V	800	4
80	AC 400V/690V, DC 250V/440V	800	4
100	AC 400V/690V, DC 250V/440V	800	4
125	AC 400V/690V, DC 250V/440V	800	4

DC Knife Switch Features

Multifunctional Mounting: Compatible with both DIN rail and screw installations, offering flexibility for various low-voltage switchgear setups.
Coverless Wiring Design: Allows for safe and quick connections without the need to remove a protective cover, simplifying the installation process.
Ergonomic Operation: The handle is ergonomically designed for easy manual operation, enabling smooth opening and closing of the switch.
Compact Size: Its space-saving design makes it ideal for tight photovoltaic installations and low-voltage distribution panels, helping to reduce costs.
High Flame Resistance: The housing is made from V0-grade flame-retardant material, ensuring excellent fire resistance in harsh working conditions.

DC Knife Switch Advantage

The DNH51 DC switch features a housing made from V0-grade flame-retardant nylon, designed to perform reliably in temperatures ranging from -35°C to +70°C. Even in extreme conditions, it maintains its high durability and performance, making it a dependable and safe choice for photovoltaic DC applications.

secondly， The DC Knife switch pairs effortlessly with PV fuse holders like the DNPVF DC Fuse Holder and is suitable for use in a PV Combiner Box, enhancing the safety and efficiency of your solar power system.

DC Knife Switch Application Scenarios

The DNH51-125/4 DC Knife Switch is widely used in low-voltage switchgear systems, especially in photovoltaic (PV) applications, for isolating power sources and switching circuits in a no-load state. It is ideal for:

Photovoltaic (PV) Power Plants

Residential Solar Power Systems

Commercial and Industrial PV Installations

Low-voltage Switchgear Applications

It ensures smooth operation and effective isolation, enhancing the overall safety and performance of solar power installations.

Normal Operating Conditions

Altitude does not exceed 2000 meters;
Ambient air temperature does not exceed +40°C and is not lower than -5°C;
Relative humidity of the air does not exceed 50%;
In environments without explosion hazards, and no presence of corrosive metals gases, or dust that can damage insulation;
No significant vibration or shaking is present.

This product complies with the GB/T 14048.3 standard.

Where Are Knife Switches Used?

A knife switch is a simple, reliable device used to control electrical current by manually opening or closing a circuit. While modern technology has evolved, knife switches remain widely used due to their durability and high current-handling capacity. Here’s where knife switches are commonly applied:

1. Industrial Electrical Isolation

Knife switches are used in industrial environments to isolate electrical circuits for maintenance or emergencies. Their ability to handle heavy currents makes them ideal for machinery in manufacturing plants, chemical industries, and other high-voltage settings.

2. Power Distribution Systems

Knife switches are vital in power distribution for safely isolating parts of the grid during maintenance. They are frequently used in low-voltage switchgear and distribution panels to control electricity flow, especially in solar and wind energy systems.

3. Emergency Power Cut-Off

In high-voltage systems, knife switches provide a quick, manual method for shutting down power. They serve as reliable emergency cut-off devices in power plants and industrial settings, offering immediate visual confirmation of disconnection.

4. Renewable Energy Systems

Knife switches are key components in solar and wind energy systems. They allow safe disconnection of solar panels or battery systems for maintenance and ensure smooth operations in renewable energy infrastructures.

5. Educational Demonstrations

Due to their visible design, knife switches are used in laboratories and educational settings to demonstrate electrical principles such as circuit continuity and current flow.