HAVELLS Isolator Price List w.e.f 5th September 2013 (VIEW)HAVELLS Customer Care No:+91-120-4771000
L&T Isolator Price List w.e.f 1st November 2013 (VIEW) L&T Customer Care No:18002094545
Introduction of Isolator
An isolator (UK terminology) or disconnector (US terminology) is a switch used to isolate a section of a circuit from any energised conductors, by presenting a visible break in the circuit. Isolators are not designed to break load currents (unless fitted with optional arc-breaking feature) or to break fault currents. In high-voltage systems, isolators are used in conjunction with circuit breakers -with the isolators opened after a circuit breaker has opened the circuit, and closed before the circuit breaker closes the circuit. For example, before one can perform maintenance work on, say, a high-voltage circuit breaker, the following sequence must be followed:
1. The circuit breaker is opened, breaking the circuit.
2. Isolators located on either side of the circuit breaker are opened, presenting a visible break between the isolator and energised lines.
3. Temporary earth (ground) connections are applied to each side of the circuit breaker.
4. Barriers and warning signs are erected around the circuit breaker to define the permitted work area.
5. A permit to work card, listing the work to be performed, and any potential hazards, is issued to the personnel who are to maintain the circuit breaker.
Diffrence between Isolator and Circuit Breaker
Major difference between isolator and circuit breaker is that isolator is an off-load device, whereas circuit breaker is an on-load device.
(An isolator switch is part of an electrical circuit and is most often found in industrial applications. The switch does exactly what its name suggests in that it electrically isolates the circuit or circuits that are connected to it. Such a switch is not used normally as an instrument to turn on/off the circuit in the way that a light switch does. Either the switch isolates circuits that are continually powered or is a key element which enables an electrical engineer to safely work on the protected circuit.
Isolator switches may be fitted with the ability for the switch to padlock such that inadvertent operation is not possible. In some designs the isolator switch has the additional ability to earth the isolated circuit thereby providing additional safety. Such an arrangement would apply to circuits which inter-connect power distribution systems where both end of the circuit need to be isolated.
Operation of Isolators
While opening a circuit, the Circuit-Breaker is opened first, then Isolator is opened and then in last, Earthing Switch is closed.
Whereas while closing a circuit, Earthing Switch is Opened First, then Isolator is closed, and then in last, the Circuit-Breaker is closed