The isolation switch and the disconnector belong to the cutter type switch. Regardless of shape, structural principles, methods of operation, they are very similar. But they have very different points, must be strictly differentiated.

The electrical isolation switch is one of the simplest switching devices used to break the circuit below 500 volts, it can only be manually operated. As the circuit is often broken arc, so it equipped with arc extinguishing device or fast break contact. In order to increase arc ability, the knife is generally shorter.

Isolation switch has high voltage, low voltage, a pole, three poles, indoor, outdoor, it does not have a special arc device, can not be used to connect, cut off the load current and short circuit current, only operation in the case of electrical line cut off. Its main role is to isolate the power supply, there is a clear disconnect between the power supply and the electrical equipment, so do not have to consider the arc. In order to ensure reliable isolation of power, to prevent over-voltage breakdown or flashover, The knife is generally longer, interphase distance is also larger.

In short, the isolation switch can not be used as a disconnector, and the disconnector is only allowed to isolate circuit in the not high voltage, and must be used in series with the fuse.