Why is it necessary to install a rotary handle on the molded case circuit breaker

The rotary handle is used to control the operation of MCCB through rotation control.

For molded case circuit breaker, the handle has three terminals: on, off and reset.

Before explaining the use of the rotating handle on molded case circuit breaker, let's see why the molded case circuit breaker is used.

Molded case circuit breakers have three main functions:

Overload protection - the current exceeds the rated value and lasts longer than normal application.

Electrical fault protection - very high current must be interrupted immediately during faults such as short circuit or line fault.

Electrical Switch for disconnection - this is less common function of circuit breakers, which can be used as manual disconnection switches in case of emergency or maintenance operations.

In order to achieve these functions, conventional switches cannot be used because the interruption of high current during fault may lead to arc. It is safer to use the rotary handle.For example, when we turn on / off a conventional switch, you may see an arc, which occurs when the air around the switch contact is wet, the hand is wet or the voltage is low.

If you want to turn off a circuit with over-current, it is not safe to use a conventional switch. Therefore, people choose to use rotary switches.

There are two types of rotary handles:

1. Direct Rotary Handle (Mount the handle on MCCB & cut out the opening in the panel door).
2. Extended Rotary Handle (Mound base unit on MCCB & handle on panel door. This having a provision that the panel door cannot be opened in MCCB ON position).

Click here to see details on rotary handle, or contact us to get one!