There are 5 MCB types,
An MCB’s circuit rating is given in Kiloamps (KA), and this indicates the level of its ability to work.
For example:-
A domestic MCB would normally have a 6KA fault level, whereas one used in an industrial application may need a unit with a 10KA fault capability.
Note:-
The speed at which they trip depends upon the level of overload, and is usually determined by a thermal device within the MCB
- B - above 3 In up to and including 5 In (Instantaneous)
- C - above 5 In up to and including 10 In (Instantaneous)
- D - above 10 In up to and including 20 In (Instantaneous)
- K -above 8 In up to and including 12 In For the protection of loads that cause frequent short duration (approximately 400 ms to 2 s) current peaks in normal operation.
- Z - above 2 In up to and including 3 In for periods in the order of tens of seconds. For the protection of loads such as semiconductor devices or measuring circuits using current transformers.
An MCB’s circuit rating is given in Kiloamps (KA), and this indicates the level of its ability to work.
For example:-
A domestic MCB would normally have a 6KA fault level, whereas one used in an industrial application may need a unit with a 10KA fault capability.
Note:-
The speed at which they trip depends upon the level of overload, and is usually determined by a thermal device within the MCB