Rated short time withstand current is the value of short time withstand current, assigned to the equipment by the manufacturer, that the equipment can carry without damage, under the test conditions specified in the relevant product standard.
It's generally expressed in kA for 0.5, 1 or 3 seconds. This is an essential characteristic for air circuit breakers. It is not significant for molded-case circuit breakers for which the design targets fast opening and high limiting capacity.
Icw is different from one breaker to another and its value can be found in the product catalogue.
Masterpact MTZ catalogue
Masterpact NT/NW catalogue

Released for:Schneider Electric Ireland