If you consider the plethora of rules and regulations surrounding this trade and the amount of bickering amongst all professionals about testing, and of the importance of testing, there is one absurdity that sums it all up. There is no requirement to test the operation of an mcb! And no means of testing one available. So every single mcb fitted is never tested. It is all just accepted that they work. If only the faith exhibited in mcbs could be spread to other areas.