"Weak" Electricity

[Dave Plowman (News)]

It may not be quite to the letter of the regs but nothing really unsafe about it - if you attempt to draw more than the lighting circuit rating the MCB will just trip. And lighting circuits use generously sized cable compared to rings. That's assuming you have modern lighting wiring with an ECC - older systems didn't require this. Strictly speaking you should use a socket other than a standard 13 amp one - same as you'd do with table lights etc fed from a lighting circuit - to prevent a heavy load being plugged in by mistake. 3 pin 5 amp round pin types are the norm.

My guess was it is wired across a switch pair rather than feed. So ends up in series with one of the upstairs lights. Is it easy to trace the wiring back to the junction box etc it's picked up from?

[Frank Erskine]

It would be quite handy if you could get wall-warts with 3 pin 5 amp 'plugs'. On occasion I've needed to fit audio pre-amps (without phantom power-feeds) in remote locations and had to fit 13 amp sockets.

[Phil B]

** But have you seen reports of Psychic society meetings cancelled due to unforseen circumstances? ***

To e-mail, change noise into sound.

Dave,

a) You are quite right about MCB ratings and behaviour - it's accurate Physics but I know you'll agree it's poor Engineering which we should not encourage. Can we assume the lighting circuit earthing is intact? I'd prefer for the cartridge fuse in the 13A plug to go first rather than plunging me into darkness in the loft, especially with a possibly faulty device nearby.

b) Yes, agreed that connection across a switch is a possible scenario and that tracing back is the best answer. In that case, the OP should be able to find a light switch which causes the loft appliance to go out when he puts the switch on. Note that if this is the case then he is warned that BOTH L and N connections in the loft socket will be live. Also, even when the bedroom light is 'off' then the bulbholder may well be live. Another scenario is a dirty/faulty socket or test lamp. Either way though, tracing back will be necessary OR he could just dis-connect the socket, insulate the end of the cabe with a block (one of those round things) and rewire the socket properly. the next question might be 'how do I connect a socket in my loft'....

Phil

[Dave Plowman (News)]

Poor or not it is frequently come across for things like aerial amps or DAs. Or indeed the application the OP used it for.

I mentioned that. But you should never assume anything with electricity.

But the cartridge fuse won't go first if rated for an appliance higher than the circuit. In the case in point you'd need to fit an FCU before the socket with a suitable fuse. Which, of course, will be replaced by a 13 amp one after blowing due to overload.

Yes - we've been through all that days ago earlier in this thread.

Depending on the position of the light switch. So not really a guide for fault finding.

Might indeed. But if it is there's a chance that light will be on all the time. Which is what I asked the OP earlier - do try and keep up. ;-)

Saying it *must* be wired to a power circuit rules it out for many - without causing a deal of disruption. There's nothing 'wrong' in running it off a lighting radial - but it should be clearly marked as such.