Cable fault location meters , anyone used them before ?

[JD6400]

We had a break down call out on Thursday to a stable yard we have just completed , it turned out that the 500m 95mm three phase sub main that was installed as a single phase for the time being until they can afford a three phase meter upgrade has been compromised on the currently used brown phase and also on the black phase which is dormant at the moment !
The grey phase and neutral bell out fine .
So we have got the yard up and running at the moment , but we need to go back and locate the problem now !
Have any other forum members had dealings with cable fault location gear and can you recommend which is best ?
We have been quoted around £550 + to hire some , but i always prefer to look at buying reconditioned kit at a all be it higher cost rather than pay a dead loss hire fee .
It would not be so bad but the run was moled under two private tarmac roads and strait across the main access yard and lorry park park for the whole complex , without being ducted ( clients request to keep cost down along with using their own labour to lay it ) , BUGGER !!!!!!!!!!!!

 

[i=p/u]

sounds intersting , im fed up installing 10A light switches and doing domestic, i kn ow already

 

[Heisenberg]

Just out of curiosity, who's gonna be paying for all this? As it was only installed a couple of months ago, is the client blaming you and expecting you to cover the cost?
Sounds like the sort of job that could turn a profitable year into a not very profitable one if that's the case :dead:

 

[lamb]

If there is water running out of the cable, there could be a lot more to chop out than just the damaged section.
If any joints or terminations are lower than the cable fail point, they will keep getting damp.

 

[Knobhead]

The outer sheath is compromised so the armours are at risk. I know it’s late now but this is where testing the armouring to earth pays off, proves the outer sheath isn’t damaged.
DP, what tests were done on the cable before putting in service?

Sorry but the more I think about it this cable is going to be a write off.

 

[lamb]

Agreed, a large section will need to be cut out at least.
Steel has a co-efficient of expansion of 6:1 when oxidised, so when the armour rusts it will further ruin the sheath and pierce/compromise the bedding and insulation.
I would still try to salvage any good part of the cable if it is dry and sheath not leaking to earth.

 

[WPD Lad]

I'll have a Kelvatek Reflekt in around 3 weeks if you can wait, failing that I've got a boggo cat and genny

 

[Knobhead]

Nice bit of kit.

 

[JD6400]

Right then first off , thanks for all of the replies and apologies for not getting back until now ( just getting over a second bout of tonsillitis in the last two weeks, so had a lay in ).

Richard / UK Meter , this seems the way to go but from what you have mentioned it sounds a bit like rocket science ?

Heisenberg , as far as we are concerned it has nothing to do with us but the client also thinks the same for him self !
This is how it has developed so far - To save money we sourced and specked the cable from our usual wholesalers and the client payed for it direct , one of our apprentices then subbed direct to the client and hired a digger to lay the sub through the fields and borrowed one of our moles to go under the roads , this was direct to the client .
The client also employed the chap building one section of the complex to go through the yard at the top and back fill it ( which is where i think could be the problem ).
All we did was connect both ends , i know our man had gone direct but we still feel some responsibility .
It will be around a £20,000 hit if it all goes pair shaped ! ( job had already over ran the budget by £12,000-£13,000 and cost us several £0000 more than the original quote so not impressed at the moment !!!!!!!!!)

Tony , it was megged out and at the time all was good but it was very dry at that point and had been since it had gone in the hole .

WPD Lad , thanks for the offer maybe we could hire your service's if that would work as if we do not buy one then i would far more prefer to give the money to some one from the forum !

 

[Knobhead]

I’ve fallen for clear tests before, about a mile and a quarter of 70mm, so there were a couple off joints in it. Perfect readings. And then the rains came. Oh dear!
It took me weeks to find where one of our wonderful process guys had been cleaning up with the aid of a front-end loader.

It would be good if you can get WPD Lad on side.

 

[UKMeterman]

Hi,
A TDR for power cables can be hired here biotest T625 cable fault locator | hire | inlec They are quite easy to use, they just need connecting up and details of the type of cable in use.

 

[UKMeterman]

Next time you install a cable like this, don't use a standard megger use megger MIT520/2 5KV diagnostic insulation resistance tester | hire | inlec this can detect a whole host of insulation problems, before the insulation suffers total failure. A TDR can also spot some subtle changes as well so it may be an idea to do both.

 

[UKMeterman]

As regards faulty underground power cables and horses remind your customer about the newbury racecourse incident. Two horses were electrocuted...

 

[mogga]

google RADIO DETECTION their RD400 with a GENNY can be used for fault location practice with a dod laid on top of the ground get to know what to listen for then follow the cable sound along the route WATCH for inducted sound on any gas/water pipes tho If used correctly this could assist you

Vhttp://www.inlec.com/electrical-tes...etection-rd400pxl-cat-genny-cable-locator-p33

 

[mogga]

SRC training center use to have some crackin specialist fault locating kit and as Tony says clear cable can turn into down all over the place when the rain hits the ground as for crossing the yard we had this when they decided to lay tar on a yard and the pressure pushed a brick through a 75mm4 core that was my first big joint

 

[Engineer54]

None of these cable fault detectors are easy to use, ...well they are if you know how to interpret the signals the machine is showing you. I've seen experienced operators totally flummoxed at times!!

Your best bet is to get a recognised company in to find this fault, they will generally guarantee the location of the fault to within a metre of where they say it is. Other than that, you could end up digging down in umpteen locations if your not experienced in using these fault locators... lol!!

What the betting that either the floor of the trench wasn't cleared of sharp protruding stones and debris, or that this trench was backfilled without the correct sand bedding....