Circuit Breakers: Making Capacity vs. Breaking Capacity

When a current-carrying circuit is broken by the breaker contacts moving apart, there will be a very high electric field while the contacts are still very close. This is likely to ionize the air between the contacts - allowing the current to keep flowing. As the contacts move further apart, this arc can stretch out to fill the gap.

This cannot happen when the contacts are being made, because the gap will only be small enough to give a high enough field strength for ionization for the last few milliseconds as they close.

This sounds like homework to me!

Good afternoon to all

The making capacity is the peak value where as the breaking capacity is express in RMS

as seniors said arc tends to establish its state --

v max =1.414*v rms

hope it helps

See the this thread and the answer is there:

http://cr4.globalspec.com/thread/37632