40A MCB will trip, but 63A won't: Is this logic even logical?

[Tom.G]

It makes a lot more sense to connect them to appliances that are most likely to electrocute someone, ...than to use them on expensive things. They aren't intended to protect the things, they are meant to protect you.

Well, even hammers have more than one use.

The combination appeared to disconnect everything from an over-voltage condition.
That puts it in the SUCCESS bucket for me.

Remember that the surge protectors often have a fuse in series so that when/if the snubber fails shorted they don't go up in smoke or start a fire.

If you have any protected outlet strips with a pilot light on the surge protector indicating they are functional, see how many of them are still on. (often a Red LED)

Of the four here that are connected directly to the line, one has failed; that's not a particular problem because it is a 'convenience use'; all it is used for is a couple of fans and occassionally a vacuum cleaner.

Cheers,
Tom