An isolator is a type of electrical switch used to disconnect electrical circuits or devices from the power supply, providing an extra layer of safety during maintenance, repair, or troubleshooting. Isolators are commonly used in electrical power systems, substations, and electrical panels to ensure that electrical circuits are completely de-energized before work begins.

The primary function of an isolator is to separate or isolate parts of an electrical system from the rest of the network, preventing the flow of electricity. This ensures that electrical technicians can work safely on the circuit or equipment without the risk of electric shock. Isolators are typically used in conjunction with other protection devices, such as circuit breakers, to ensure the safety of both electrical personnel and equipment.

Isolators are classified based on their application, voltage rating, and design. Some of the common types include:

• Rotary isolators: These operate by rotating the handle or switch to physically disconnect the contacts, often used in low-voltage circuits.
• Disconnector isolators: These are used in high-voltage systems and provide a visible gap between contacts to indicate that the circuit is disconnected.
• Knife-blade isolators: A traditional design that uses a blade to disconnect the electrical contacts.
• Motorized isolators: These isolators use motors for automatic switching and are typically used in industrial applications.

Isolators differ from circuit breakers in that they are not designed to interrupt live current during normal operation. Instead, they are intended to be used in situations where the system is de-energized, providing a visible indication that no current is flowing. Therefore, isolators are typically installed in switchgear panels and distribution boards as a secondary measure for safety.

In summary, isolators play a critical role in electrical systems by providing a safe method for disconnecting circuits during maintenance or repair work. They are essential in ensuring that electrical personnel can work with confidence and avoid electrical hazards.