Circuit Breakers

[AliasAggers]

This is not a computer-related matter.

I have a problem that baffles me, concerning electric circuit breakers, and would welcome any suggestions.

One of my electric wall sockets is used for powering a four-socket switched extension strip that feeds a fluorescent light,
my musical keyboard, and a shredder and occasionally an electric iron. There is no problem while it is in use, but sometimes,
when I turn it OFF at the wall socket, it knocks out the main circuit breaker and I lose all power throughout the apartment.
This is something new to me. Any suggestions?

[Suff]

Is the main breaker a RCCD? I.e. does it have a test button on it?

If so the socket is losing power to earth when you switch it off and tripping the circuit by earth leakage. If not it could just be shorting the trip switch by actually causing a short circuit on switch off.

One or the other.

[Workingman]

Is the four gang set extension socket surge protected?

Or.... There is an anomaly and it goes something like this:

Your home circuit breakers (CBs) are surge protected, so if a spike is detected, say a failed light bulb, they throw out on that circuit. Your four gang socket could also be surge protected so that if something on it fails it does the same job as the main CB, but intercepts it before it gets there, so it turns itself off. Only the items on the four gang socket get turned off - so goes the theory.

Now for the silly part.

You have power from the home main via the CBs to the wall socket, so that is active. You have an extension plugged in, so if the wall socket is "on" that is also active. If you have items plugged in to the individual sockets on the extension and they are switched "on" they are also active. Now you can turn things connected to the extension independently on or off at their own switches in order to use them, but you effectively have one power line all the way to each device and shared by them.

What can happen if those things are turned "on", even though they are not being used, is that when you turn that whole bank of stuff off all in one go, as in turning the wall socket off, the house CB detects a spike and acts to save itself. It does not always happen and it can depend upon how sensitive the surge protection down the line is.

Try turning off all the items plugged into the extension one at a time before then turning it off at the mains and see what happens.

[AliasAggers]

Thanks boys. You have thrown some light on mu problem, and it makes sense to me.

I'll modify my procedures now, and see if my problem is solved.

The problem of the main circuit breaker cutting out did not happen every time I switched
off the wall switch, which does seem odd. I'll let you know how I get on now that the
switches on the extension strip are all turned off except the one I have been using.

[Suff]

That did bring a thought to mind. There is, as WM says, capacitor surge protection on each device plugged in. It could be a rogue capacitor discharge when you switch off. Also the fact that you have a switched bar might influence the fact. As WM says, if you want to see if it is a device on the bar, you can switch them on, one at a time, then switch it off at the wall socket.

Just a point to note. Each time a breaker breaks, it wears a bit. Enough wear and it starts to break at a weaker surge.