alo brought next idea :
A low frequency signal tracer kit would find it.. BT use them.
If its a longer cable BT had a unit which fired a pulse down the line, then measured the time for the reflection to come back. Time was an indication of the actual distance to the break.
on 11/02/2022, williamwright supposed :
Not if you do it right. The longest bit will be half of the original length.
Ian Jackson submitted this idea :
Grounding the other two will stop that.
Le 11/02/2022 à 20:31, alo a écrit :
If your DMM does capacitance measurement measure the capacitance between the broken wire and good ones from both ends. Do a little bit of maths :-) Very useful too to find the length of a long roll without unrolling
Unlikely if it is an insulated earth wire.
There are a few, but it depends on what kit you have...
Apply mains voltage to the wire, and use a non contact volt stick or meter.
If you have a network cable tester, some have a cable length measurement capacity using the capacitance detected between two cores. You could set the calibration against a 1m length of the same stuff for a direct reading, or measure from both ends and use the ratio.
If you have a DMM or LCR tester that can measure low capacitance, then again as above.
If you a have a network / comms style signal injector and cable tracer, that may also let you "hear" where the break is.
If you have a scope and a function generator, then inject a square wave with a sharp rise time into one end and look for the reflection from the unterminated end. Alternatively build yourself a small pulse injector (google "poor man's TDR" for examples - usually a chip with a few Schmitt trigger inverters - one setup with a feedback connection to make an oscillator, and the others just to really square up the output)
Yes, they are handy too if you do much of that sort of thing. But I'd argue that even if all you do is replace a fuse in a plug, it is worth having a volt stick because that lets you check almost instantly whether the fuse has gone.
Yes it will
Out of interest what's the cost of a whole new replacement? Some things just aren't worth the buggeration factor.
How did you discover this fault?
Voltsticks and flex?
Not if it is near enough to the end, and if you grip and pull firmly as Dave said.
Is the Russ Andrews product legal? Although certainly not unique, thought that one of the 'good practice' safety features of the UK plug and socket was that the earth pin was at the top, and this helped prevent anything dropping or being poked from above contacting the power pins. Or was this requirement superseded when our power pins became partially shrouded?
I do not think it matters. Which way up are the holes on a 4 way extension lead or 4 way trailing extension lead?
It certainly would put strain on the flex from the plug. As it's not a fixed socket then an EICR would not to cover it.
And the pricing is wrong. It should be £1699.99 to fool the gullible:-)
Yup. Just tried to make sure I'm not talking bollocks:
Fluke VoltAlert 1AC-E a bit iffy. It needs going round the cable, and still sometimes it doesn't light anywhere round, though the cable is known good. If it doesn't light, I still won't be licking that wire... a bit disappointed, thought Fluke would be better.
Then a MASTECH MS8900 which lights *and* beeps -- this is good for sticking it somewhere, wandering off and switching off circuits and listening until the beeping stops. Works a lot better, still needs going round the wire in places.
This I tried on two-core and three-core flex, all "no load", so just volts no amps. Probably better with a load? -- but the OP wants to find the location of a break, so no current...
Thomas Prufer
FFS you don't pull on the insulation. As Dave said, you pull on the
*conductor*.
I'd have expected an E-L or E-N fault to have tripped an RCD. If the OP uses it without RCD protection perhaps best to find such a fault now in controlled conditions.
I know a volt stick needs no earth in the target conductor[1]. But AIUI Ian was concerned about spurious potentials in the phase conductors where ISTM earthing them would make a difference.
[1] or indeed in the user in some cases:
Of course - but even if you pull only the conductor, if the break is more than a couple of inches down the cable, you'll not be able to move it.
They sense the electric field, not the magnetic field, so the presence/absence of load should be irrelevant
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