INTERLOCKING....

If the generator is intended to be a Stand-by power source (i.e.) the generator will be made ON only when the EB Supply is not available, then the following interlocks are suggested:

i) Mechanical Interlocks using Castell Key Interlocks - Two Locks with one key such that only one breaker can be made ON at a time and the key can be removed from the lock only when the breaker is in OFF condition.

(or)

ii) Mechanical Interlock using Clutch wires between the two breakers so that only one breaker can be made on at a time.

iii) Electrical Closing interlock, such that the breaker auxiliary N.C. of one CB is wired in series in the closing circuit of the other CB.

iv) Electrical Tripping Interlock, such that breaker auxiliary N.O. of one CB is wired in the Trip Circuit of the other CB.

v) Ready to Close signal: The N.C. auxiliary of one CB is wired in teh Ready to Close CB of the other CB.

Nowadays the breakers can be closed mechanically from the "Breaker ON" pushbutton provided in the breaker.

The positive interlocke would be to provide under voltage assembly for both the breakers.

The NC of each of auxiliary contact of the breaker to be wired in the under voltage coil circuit.

In this case the UV coil will not pickup when the other breaker is on condition.

The breaker can not be closed even mechanically when the other breaker is in on condition.

If the two breakers are side by side, a simple mechanical interlock consists of a sliding bar that covers one breaker handle at a time.