Busbar not connected!

For the types with "cage" style clamps it is not that difficult to insert the MCB with the finger on the bus bar behind the cage. You can then do the screw up tight, but it is only gripping thin air!

You need to make sure the cage is wide open when inserting the bus bar finger. I normally check that the MCB won't lift off the bar if you unclip it.

Yes. I was taught that when closing a large breaker (of the type that you pump up pressure and then hit a release for the pressure to fire it closed), you stand as far to one side as possible and never in front.

I do recall many moons ago, in the box room the light would sometimes not come on. On looking in the rose a similar fault to what you describe had occurred when fitting the wires so the wire was almost just resting in a gap on top of its clamping bit, and connected by the little bit it was wound around the screw on the wrong side. That had to have been like that since the 1970s, and lasted until the mid 90s. Mistakes happen. its life I guess, at least it was not one of them there cheapo roses Woolworth used to sell with just a row of screws and no clamping bit at all!

Brian

It was probably my error.

It wasn't the one I fitted was it?

Haha, I've meddled with it since, on balance i'm happy to assume the error is mine!

I am curious as to why people are turning MCBs on and off.

email or WhatsApp me

I do it because it is the only internal manual control on my heat pump.