Circuit Breaker

Old Heinemann and Fuchs distribution boards do not hold the new QA range circuit breakers.

Correct, but you can buy adaptor plates that convert Heinemann and Fuchs distribution boards to accommodate the new mini rail style breakers.

Is the kA rating on a circuit breaker really important?

Yes, it is one of the most important factors to take into account when selecting a Circuit Breaker.

Circuit breaker is getting hot, how much heat is allowed?

All units will get hot under 100% rated current. Dependent on the cable size used and the atmospheric temperature, the operating temperatures could be affected.

On electronically adjustable breakers can the Amp rating be adjusted while the breaker is live?

You could adjust it, but if you lower the amp rating, there is a risk of tripping the circuit breaker.

Why would Curve 1 circuit breakers trip before Curve 2 circuit breakers?

Curve 1 should always trip last in a discriminated system as it has a slower tripping curve than a curve 2. Curve 1 is the orange toggle breaker that is a slow tripping circuit breaker, has a 10-20x inrush current, whereas Curve 2 has a 5-10x inrush current rating.

Can any 6 kA breaker be used downstream in a cascaded system?

Only tested and approved 6 kA circuit breakers can be used.

What does tested combination in a cascading system mean?

It is vital to ensure that the system you are using has been tested with the products been used. As soon as a product is changed in the system it is no longer cascaded, and should not be used. When cascading always refer back to the Manufacturer to ensure that the system you use is allowed.