anyone recommend an earth leakage clamp meter ?

[stj]

well, the constant resistance may be caused by carbon tracking!
i wonder if some type of RF injection would help find the spot?

[stj]

also, is it roughly 60k or did you use a meter with lots of digits?
maybe a precision meter would help position it.

[petehall347]

also, is it roughly 60k or did you use a meter with lots of digits?
maybe a precision meter would help position it.

it settles roughly 60k .not exact as it does change a bit and takes a few seconds to settle like its also picking up capacitance which i expect on such a long run . i really should have use the megger on it , when i swap out the isolator switch i will use the megger instead of the dmm . i was nursing a huge hangover and shouldn't really have been messing around with live mains . i had to disconnect whilst checking stuff . where the wires connect to the supply is a dark place and my torch battery decided to run rather low on charge so was hard to see things . its a bit odd as a few times the 60k wasn't there at all and had me touching my meter leads together for my sanity . another thing i noticed was the armour was connecting to the earth wire so i guess there is a split letting water into the cable . i wa told there is a kink in the cable that's been there a long time but i haven't looked at that yet . might have to check that out to see if its getting warm .

[redwire]

The 60k reading will move - the multimeter (Ohms) DC current causes electrolysis like charging a battery with the water and metals there. Try flip polarity and watch the reading.
Another approach is measure DCV to get an idea if it's wet. 3-wire? Or measure Ohms between all conductors and the armour, 4 possible readings to see if how much is leaking to what.
Line/Hot will make water boil and steam and make gurgling sounds if immersed, as a give away.
If many wet readings, I'd prepare to dig up the splice. The water will eventually corrode the conductors and the cable go open circuit.

Do you have frost and soil heaves? That moves cables around unless 1-2m below surface here.

[petehall347]

The 60k reading will move - the multimeter (Ohms) DC current causes electrolysis like charging a battery with the water and metals there. Try flip polarity and watch the reading.
Another approach is measure DCV to get an idea if it's wet. 3-wire? Or measure Ohms between all conductors and the armour, 4 possible readings to see if how much is leaking to what.
Line/Hot will make water boil and steam and make gurgling sounds if immersed, as a give away.
If many wet readings, I'd prepare to dig up the splice. The water will eventually corrode the conductors and the cable go open circuit.

Do you have frost and soil heaves? That moves cables around unless 1-2m below surface here.

yes its 3 wire but now using 2 of them . the armour is also floating but appears to be grounded somehow so the outer casing is compromised maybe at the splice but i would expect that to stay wet longer being buried . one thing to note is only some of the cable is buried the rest is laying on the ground . i am very tempted to cut it roughly in half to see which half the problem is in . then if definitely in one half cut that one in half and replace the bad quarter to save him loads of money .

[stj]

the armor is supposed to be earthed, the metal bits that mount the wire to a box see to that.

[petehall347]

the armor is supposed to be earthed, the metal bits that mount the wire to a box see to that.

yes i know it should only connect at supply end really in case of a fault that could make all grounds live . anyway both ends disconnected for testing at the moment . i cant see this causing a problem just when it rains

[CapLeaker]

yes i know it should only connect at supply end really in case of a fault that could make all grounds live . anyway both ends disconnected for testing at the moment . i cant see this causing a problem just when it rains

Did you do an insulation test yet?

[petehall347]

Did you do an insulation test yet?

if you mean with the megger not yet . will do once i have the new switch and wires disconnected both ends , i could also do a psc test but not sure if that will help here
this is same as my insulation tester .

[CapLeaker]

if you mean with the megger not yet . will do once i have the new switch and wires disconnected both ends , i could also do a psc test but not sure if that will help here
this is same as my insulation tester .

Yes, with a Megger or equivalent. This should show leakage real fast. I use the Fluke 1587FC for all these leakage tests. I don’t use it every day, but every time I need it, it’s a freaking god send for me.

[petehall347]

insulation test failed . especially live to ground and ground to armour 0.0 others at 0.3 .. they all should be better than 1.0 hardly any difference testing from both ends of the swa cable .

[petehall347]

mystery solved when one of the lads was looking for the resin joint i did years ago after some idiot lit a fire on it . this is jcb damage from a year or two back . i did warn him about the cables . looks like he badly damaged it then attempted to do a quick tape up job . .. makes the mind boggle it does . now we have to get another resin kit and do a proper repair ..

[CapLeaker]

Sweet! I figured it would fail that insulation test and there must be some trouble somewhere. Glad you found it.

[sam_sam_sam]

mystery solved when one of the lads was looking for the resin joint i did years ago after some idiot lit a fire on it . this is jcb damage from a year or two back . i did warn him about the cables . looks like he badly damaged it then attempted to do a quick tape up job . .. makes the mind boggle it does . now we have to get another resin kit and do a proper repair ..

Why do you not have this cable in a outdoor rated conduit in this country you are required to use outdoor conduit for running electrical wiring except for landscaping lighting 12 volts or under that voltage if I was running landscaping lighting and it was going to be permanent I would use conduit even for this

[petehall347]

Why do you not have this cable in a outdoor rated conduit in this country you are required to use outdoor conduit for running electrical wiring except for landscaping lighting 12 volts or under that voltage if I was running landscaping lighting and it was going to be permanent I would use conduit even for this

its swa steel wire armoured it can live outside for 50 years if some idiot doesn't damage it with a large machine then try and hide the fact after being told it was there . the repair wont take long but finding the damage has taken hours and money . if it was in conduit matters might have been much worse . cant even imagine pulling over 100 metres through conduit around bends and over uneven surfaces ,

[sam_sam_sam]

Unfortunately you can do anything for someone who does not listen you when you tell them that are electrical wiring in a certain place or area and what is even worse is that they do not tell you that they damaged it so it could have been fixed properly the first time what kind-a contractors are these people anyway

The reason why you use plastic outside rated conduit is that when you are digging you will see the conduit and you know where the wiring is yes we have underground cable here but I still put it in outdoor conduit anyway

I would agree with you if it gets damaged it is harder to deal with but me personally I do not like making splices that are underground for any reason I would rather just have it come up three feet and go back underground for peace of mind and not have breakers tripping when it rains real heavy but that's just me

[stj]

it's only 240v though - atleast it wasnt 3-phase

[petehall347]

that's better now ....

[petehall347]

still some insulation leakage going on but that bit looks the worst from i can see , might be the old joiner letting damp in . its hard to tell .. thinking of getting a thermal imaging camera and putting a heavy load on it and looking for hot spots .

[sam_sam_sam]

thinking of getting a thermal imaging camera and putting a heavy load on it and looking for hot spots .

This is probably a good way of seeing if’s a bad connection somewhere but you could still use a megger but here is how I would do where ever you have a spliced connection repair I would soak them one at a time and see if your resistance goes down or not if it does not go to the next spliced connection repair and do the whole cable that way if you do not find anything else at this point you are going to have very hard time figuring out what is still causing the breaker to trip but if it is been in service for a long time I might consider replacing it with a new one if you still have issues then I would recommend inspecting every inch of the cable for nicks and signs of corrosion or pitting of any kind check those areas as well