A DC isolator switch is a safety device intended for isolating direct current (DC) sources like solar panel systems and batteries. It commonly comprises two or more contactors, which are activated by turning a handle or rotary switch. This action enables users to securely disconnect the circuit, effectively isolating it from the power source.

DC isolator switches find typical usage in photovoltaic systems, battery storage setups, DC water pumps, electric vehicles, and comparable applications. Their mounting location, whether indoors or outdoors, often depends on the specific system they are employed to power.

What is the Function of a DC Isolator?

This switch offers versatile functionality, serving multiple purposes. It can serve as an on/off switch, providing control over the system, or function as a vital safety device for disconnecting the power source during maintenance and repair tasks.

Regarding safety, the DC isolator plays a crucial role. It ensures safety by completely isolating the power source during maintenance or repairs, preventing the risk of electrocution if individuals inadvertently encounter energized components of the system.

Furthermore, an isolator switch equipped with fuse protection serves to mitigate the risk of damage to system components and wiring due to short circuits. These short circuits often occur when disconnecting a live connection from a circuit or when a conductor inadvertently contacts a live part of the system.

Also Read: What is DC Optimiser?

What is the Difference Between AC and DC Isolator?

The difference between AC and DC isolators lies primarily in the voltage they are designed to handle. An AC isolator switch is employed with AC voltages, whereas a DC isolator switch is specifically crafted for use with direct current sources.

Consequently, these two types of isolator switches possess varying ratings and capabilities. For instance, DC isolator switches typically have ratings that are 20% higher than the circuits they are meant to isolate.

Also See: What is AC Disconnect Switch?

How to Wire a DC Isolator Switch

To wire a DC isolator switch, follow these steps:

  • Safety First: Prior to any connection, ensure all power sources are turned off to guarantee a safe working environment.
  • Proper Wiring: Utilize the correct type of wiring that matches the voltage level of your system. Employ DC-rated cables and terminals suitable for your specific setup to maintain safety.
  • Secure and Insulate Connections: Confirm that all connections are firmly secured and adequately insulated. Once the wiring is verified, proceed to mount the DC isolator switch in its designated position according to your system requirements.
  • Manufacturer’s Instructions: Always read and adhere to the manufacturer’s instructions and safety guidelines when wiring a DC isolator switch. Failure to do so may result in accidents or damage to components.
  • Secure and Clean Connections: When connecting the wires to the switch, ensure that all connections are securely fastened and free from debris or corrosion.
  • Correct Wire Size: It’s crucial to use the appropriate type and size of wire for your specific application. After connecting all the wires, verify that the switch operates as intended by conducting a functional check.

Must Read: What is DC-to-DC Converter?


Elliot is a passionate environmentalist and blogger who has dedicated his life to spreading awareness about conservation, green energy, and renewable energy. With a background in environmental science, he has a deep understanding of the issues facing our planet and is committed to educating others on how they can make a difference.

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