Current Limiting Breaker

[Grouch1980]

I never looked at the curve for a current limiting circuit breaker.

I attached the graph for one (current limiting breaker.pdf). My question is, is the diagonal line all the way on the left, labeled 'Maximum available peak current at 15% Power Factor'... is this line the same as the A-B line that you see on the graph for a current limiting fuse (see attached jpg file)?

 

[jim dungar]

I believe it is.

I did short circuit and arc flash studies for many years. I don't think I have used 'Let-through' curves more than once in the past 40 years.

 

[Grouch1980]

I believe it is.

I did short circuit and arc flash studies for many years. I don't think I have used 'Let-through' curves more than once in the past 40 years.

Same here regarding the let through curves. I've maybe used them twice.

 

[ron]

I haven't used let through curves since it became evident from published articles that the up-over-down method was unacceptable to "reduce" fault currents due to dynamic impedance. Probably 25 years ago