How to use an RCD socket?

Post date: 2019-11-10 06:26:35

My rented garage has this RCD power socket installed (or at least one that looks identical). It's acting like it's permanently tripped. Am I just using it wrong?

Yes, this is a stupid question. But "how to use a plug socket" is unfortunately too obvious for anyone to have written up a handy guide to check myself against.

This is a question about UK sockets specifically, but I suspect it's pretty universal.

What I think should happen:
0) The power socket is off, with a black indicator behind the little window. All is peaceful.
1) I plug something into one of the sockets
2) I press and release the "power" button
3) The little window shows a red "on" indicator, which stays in place
4) I switch on my appliance and... it works. Things get heated, cut, vacuumed, charged, etc. There is much joy to be had.
5) Pressing the "reset" button (or a power cut, or a fault in my appliance's wiring) trips the RCD, turning the power off.

What actually happens is that when I release the power button, I see the red "on" indicator for a fraction of a second (it's mechanical - a bit of coloured plastic moving behind the window, not a light) before it clicks back to the "off" state. It's not latching on then switching off, it's just passing through the "on" state as the button moves. I sometimes get an instant of power from the socket as it passes through the on state (e.g. the phone charger's LED blinks on), so I know there's power to the socket, but it never latches "on".

I don't think it can be a problem with what I'm plugging in: I've tried a heat gun (brand new), a jigsaw (brand new), a vacuum cleaner (recently passed a PAT test) and a phone charger. These all work perfectly in sockets in my flat. I've also tried it with nothing plugged in, and it behaves exactly the same.

From my understanding of what RCD sockets are supposed to do, I assumed this means it's faulty. However, I contacted my landlord who says they sent an electrician who tested it while I was out, and found it to be working perfectly.

So:
a) Is my expectation of how RCD sockets should work correct?
b) If not, how *should* I be using this thing?
c) Specifically, should I be able to switch it on (and have it stay on) without anything plugged into it? Or something that's plugged in but switched off?
d) If it seems there's a problem, is there anything I can do to further diagnose this before I start arguing with my landlord about whether this electrician they sent actually exists?

To forestall the obvious warnings: I have no intention of taking this thing apart or interacting with the mains supply beyond plugging stuff into sockets. Aside from anything else, if I fatally electrocute myself I'd probably lose the cleaning deposit.

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