Protection of an Under-Rated Switchgear

My thought is if you have 2 breakers in series in the event of a fault the lower rated one will trip first, and no problem (apart from what caused the fault!) but I'm not strictly an elec engineer so somebody might correct me. But how do you think an intermediate breaker would help?

Ignore this (anybody who read it). I saw switchgear but read it as automatic breaker (overcurrent protection). But I still don't see what good an intermediate one would do.

You can install it, but it would be a waste of time and money.

Hire an engineer to explain it to you.

I'm sorry, are you fooling us around? How is it possible that low breaking capacity switch gear is implemented on an upstream line?

It is quite possible that the 25KA gear has been pulled from an obsolete plant and is vastly overrated. Normally the highest rating is upstream and lower ratings feed individual sub-circuits. That is the cheapest way to install new equipment and it provides discrimination because the upstream switchgear must be able to take the whole fault current of the faulty sub-circuit plus any loading from other sub-circuits. But if they had overrated switchgear lying on a shelf gathering dust, utilizing it would be would be cheaper than buying new. The rest of us have been in a recession and looking for ways to keep costs down, where were you? The only downsides of fitting overrated items are the cost, and confusion it could cause to employees who don,t know the history of the plant.

Hi, thanks for your replies and advice in this matter. I do sincerly apologise if this sounds like a joke to you, but I only just want to seek clarification and understanding in the matter. To me, it looks like there might be a possibility but, I may have overlooked some areas.

But once again, I so thank all for the replies and comments. I will request the help of the professional engineer.