<![CDATA[Hamzavi Consultancy Company - Understanding Differences Between Isolators, Load Switch, Switch Disconnector and Circuit Breaker]]>Tue, 25 Jun 2024 08:02:40 -0700Weebly<![CDATA[Understanding difference between Isolator, Load Switches, Switch Disconnector and Circuit Breaker]]>Sat, 28 Jun 2014 17:08:59 GMThttp://www.hcco.in/understanding-differences-between-isolators-load-switch-switch-disconnector-and-circuit-breaker/understanding-difference-between-isolator-load-switches-switch-disconnector-and-circuit-breakerIsolator Switches
Isolator Switches are designed to isolate an electrical circuit from its power source. Isolator switches does not have any interruption capacity. It does not have any making or breaking capacity.

Isolator switches are only intended to be operated on open circuit. That means, Isolator switches must be closed on open circuit and then other means of device (like C.B.) to energize line or isolaor switches must be opened after opening upstream device (like C.B.) to de-energize line.

Isolator switches are purely mechanical device and it can conduct normal operational currents as well as under short circuit current for defined period.

Isolator switches complies to IEC 60947-1 and IEC 60947-3.

Picture
Image: 4 Pole Din Rail Isolator (Source: Schneider)

Load Switches (Load Break Switch)

Load switches are designed to isolate an electrical circuit from its power source under load condition. It can also be termed as on load disconnectors or load break switch (LBS). Load switches may have short circuit making capacity but it does not possess a short circuit breaking capacity.

 Load Switches are intended to be operated while current is still passing through circuit. That means Load switches can be closed or open on existing energized line.

 Load switches are purely mechanical device and it can conduct normal operational currents and short circuit current for a defined period. Load switches are capable of operational currents, making currents and breaking currents under normal operating conditions.

 Load switches complies to IEC 60947-1 and IEC 60947-3.

Picture
Image: Three Pole LBS (Source: Eurocomponents.com)

Switch Disconnectors

Switch disconnectors are combination of Load Switches and Isolator switches. Its mainly used as the main switch in low voltage distribution boards, starting and stopping motors and isolating loads during maintenance.

Picture
Image: Switch Disconnector (Source: ABB)

Circuit Breakers

There are various circuit breakers available for various application.

 Circuit breaker can be Electro Mechanical (ACB, VCB etc) or Purely Mechanical (MCCB, MCB etc) device based on application. Circuit breakers can be used with or without Isolators, Load switches and switch disconnector.

 Circuit breakers are capable of carrying operation currents, making and breaking currents under normal operating conditions; also, making, carrying fault current and breaking currents for specified time under abnormal circuit condition (faulty or short circuit condition).

Picture
Image: MCCB (Source: Terasaki, Malaysia)
]]>