Following an episode of depriving three flats of mains power for 8 hours I thought I'd buy some of those cheap volt sticks mentioned here recently.
Seem to work fine on ordinary cable but not on my armoured incomer. I suppose I shouldn't be surprised by this but clearly they're not gonna stop me drilling into another armoured cable. ;-)
Out of interest, would the type of armour make a difference (say steel versus copper)?
Tim
They aren't meant to be cable detectors. Surely a proper detector would be better?
My Kewstick Uno detects normal flex as live from any angle/orientation, it detects arctic flex as live *unless* you have the tip directly over the earth core with the tool perpendicular to the cable, but it will
*not* detect any live indication whatsoever from 2.5mm^2 SWA.
Never heard of copper armour. I'm not too surprised that they don't detect live SWA cable, especially at any distance. However a good "metal detector" ought to work, also consider a rare earth magnet which (I guess) might pick it up through up to a centimetre of plaster, but probably not much further.
I wasn't intending using it as a cable detector. My folly was to drill (deliberately) into an old copper pipe to determine whether it was gas or water (having turned off both first) prior to removing the "pipe". I forgot the third option. ;-)
Tim
Copper sheathed mineral insulated cable is fairly common, but I've never seen any big enough to be mistaken for a gas or water pipe. Still I suppose this was supplying 240 or 300 amps.
Certainly providing mechanical protection, but I wouldn't call it "armoured".
I bet that made a bit of a pop !
Andrew
Mine uses capacitive pickup, so any earthed metal stops the signal.
8 hours is a long time.NT
Ruined my drill bit. ;-) Underwear escaped serious damage though.
Tim
It was probably longer. Certainly long enough for the electric company to rig up a temporary supply.
Of course if the main fuse hadn't been hidden behind a plasterboard partition behind a radiator they might have found it a bit quicker. ;-)
Tim
MICC?
Tim+ a écrit :
The will not pick up the field through metal of any type. That includes metal screening, armouring, conduit and etc..
To help prevent your drilling an hidden amoured cable, metal pipe or similar buried in a wall, a metal detector works well.
I'd not think copper was much goosed for armouring a cable though.
Brian
Yes, one should be able to use a metal detector to find something in a wall? Brian
Also it's used with cables which don't have balanced feed/return current such as 11kV singles, although it's really there to generate an earth leakage if the cable is damaged, and is much thinner than steel armour wires. Hopefully you don't have any concealed 11kV wires in the wall!
Was it an ordinary coppr pipe, or was it a mineral insulated cable full of compressed white magnesium oxide power as the insulator)?
I do recall a Mr. Terry P mentioning standing outside in a thunderstorm in wet copper armour shouting "All Gods are bastards!" but this probably does not relate to your issue :-)
The latter, although to a fool it looked awfully like an old copper pipe. ;-)
Tim
Ah but it wasn't hidden. I just needed more nous. ;-)
Tim
Most houses built since the late 60s have an incoming supply that uses copper armour.
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