Poles, Clear Factors, and Short Circuit Levels

Dear Sir,

The Short Circuit current level is the equipment's Short circuit current rating. It may be 50 kA for 1 sec or 3 secs.Or 40 kA for 1 sec or 31.5 kA for 1 sec or 25 kA for 1 sec.

It is the closing follwed by opening of the Circuit Breaker.

Best Regards,

N.Suresh

please sir,be specific and elaborate ,becaues i am very new to the practical ground.kindly explane it along with first pole to clear factor.

with regards

partha

A1) The <...first pole to clear...> ordinarily is the line conductor in some sort of circuit interrupting device. There is no apparent <...drawback...> to this.

A2) The <...short circuit level...>, otherwise known as the prospective short-circuit current ["PSC"], is the normally-applied circuit voltage divided by the circuit impedance at short circuit at the far end. Protective automatic circuit-interrupting devices need to open safely at this level of fault. The topic pertaining to selection of cable size and circuit protection devices is known as "co-ordination".

If in doubt, consult a local qualified Electrician.