Zoomup:

... a double glazing frame maker ...

Would have been a good one for What's My Line!


I fear that good old trial and error may be required.

davezawadi (David Stone):

Short out the supply in the shed and see which fuse blows? Presumably, you cannot isolate one by one to see?

Yeh, but I still would not know which fuse had blown as they are hidden behind the M.E.M. isolator doors, and to get to them I would have to turn off to get the door open which may be a different circuit. I can not just turn everything off.


Z.

AJJewsbury:

Has anyone tried one of those circuit tracers? The kind that you plug a "transmitter" in on the circuit you want to trace and then wave a "receiver" wand around likely supply point to see which gives the strongest signal? Never had a chance to play with one myself, but in theory sounds ideal for this kind of problem. I'm hoping the cables between the meter and switchfuses are insulated & sheathed so shouldn't screen out the trace signal (unlike perhaps the SWA armour).

   - Andy.

That's the thing Andy. I have one somewhere, but years ago I did not find the thing very reliable. Anyway I am working on a three phase circuit with no 13 Amp sockets, and I seem to recall that the kit has a 13 Amp plug-in transmitter in it. You then wave a yellow space gun thing about close to the M.C.B.s in a consumer unit and it flashes and bleeps if you find the right circuit. (Supposedly)


Z.


 

davezawadi (David Stone):

That was a slight joke, but you were too slow.

The best way if you can get at the isolator tails is to put a load on in the shed and measure the load current there with a clamp meter. Go to the isolators and see which one has the same current. If none you may have a strange fault between, but it usually works.


David

An improvement on this is a contactor and timer relay in a box with a 13 amp plug and socket. Insert plug into any working socket. Plug a suitable load such as a kettle into the socket. This will cycle on and off at say two second intervals, and the sub main feeding this pulsating load is easily located with a clamp meter. More reliable than a steady load.

AdrianWint:

My preferred solution would be to use a load of significant size, say 3kW or more & have a assistant turn this ON & OFF on command by using radios or mobile phones. It should then be easy enough to find this current at the supply end.


I hear what you are saying about the cables being in trunking but it must be possible to remove the trunking lid?


I can't see anyway of doing this without some (temporary) modification to the existing system


You could always add a 13A socket short term


 

Yep, I reckon that I will have to rig up something like that. All cables and tails are in old rusty metal trunking at the meter position. I believe that the shed roof for some years leaked but has recently been repaired. I don't fancy really disturbing things too much as I don't know just what may break or fail to switch on again. Even removing the metal trunking lid maybe a hazard.


Cue lecture from sensible safety conscious forum members. (You shouldn't be adding to a circuit that may be unsound). Yes, but I have confirmed that the earthing is o.k. and the supply is suitable to add a new small three phase board  for a new machine.


Tin hat on!


Z.