Finding a break in a buried cable

Discussion in 'Electricians' Talk' started by Lowvolts, Jun 30, 2013.

  1. Lowvolts

    Lowvolts New Member

    I have recently been asked whether I can assist in trying to track down a break in a buried cable which feeds 2 lamp posts in the grounds of a building.
    I have not visited the site yet but understand that the cable run is approximately 100 metres and there are posts at approximately 50 and 100 metres.
    Although my first action will be to go on site and carry out some IR tests to determine the extent of the damage and which section it is in, (Not sure whether the problem is a short circuit or open circuit), the customer is keen to know whether we can determine the position of the damage so we know where to dig to expose the damaged section.
    I believe there is equipment which can fairly accurately determine how far down the conductor the break is, but there would be the added problem of tracking the course of the cable and accurately measuring when you were the right distance along the cable!
    If anyone has any information on where this equipment can be hired and just how accurate it is, I would be very glad to hear from you.
    Thanks
  2. sinewave

    sinewave Screwfix Select

  3. joinerjohn1

    joinerjohn1 Screwfix Select

    What if the break is in the return?  Dunno of any tracker that could accurately find the break in the return . You could bell out the cables and find if the break is in the first or second section and replace whatever section is broken.  Without seeing the job, it could just be a loose connection at one of the posts. ;)
  4. sinewave

    sinewave Screwfix Select

    What is this 'Return' one speaks of Mr Joiner?
  5. Lowvolts

    Lowvolts New Member

    Thanks for that Sinewave.I will see if I can find someone who hires out that equipment.
  6. joinerjohn1

    joinerjohn1 Screwfix Select

    Well obviously, the electrickery has to get to the lamp posts, then has to return to the CU (or wherever it's supplied from. Us joiners usually call it the neutral (or blue/black wire, depending on how old the installation is) . Dunno anyway of wiring summat up without the neutral wire Sine (unless you have a cunning plan). ;)
    I mean, if your using something to detect the electricity in  summat like twin and earth cable, then I assume it would detect the electricity in the positive (supply side) and also in  the negative (return side)  How does it then differentiate between the two?. ;)

    PS that bit of kit you linked to is well expensive. I'd expect it to make tea and answer the door at that price.  ;)
  7. Mr. Handyandy

    Mr. Handyandy Screwfix Select

    Dig it all up and wiggle the cable a bit

    Mr. HandyAndy - Really
  8. joinerjohn1

    joinerjohn1 Screwfix Select

    That's what I'd do Handy.  Or, get Western Power in to sort it.
  9. Astramax

    Astramax Active Member

    Is it a broadband cable?
  10. sinewave

    sinewave Screwfix Select

  11. joinerjohn1

    joinerjohn1 Screwfix Select

    Pray tell Sine, how these instruments work. Do they employ some sort of radio frequency transmitted along the cable to locat the break ?
  12. retiredsparks

    retiredsparks Member

    "Pray tell Sine, how these instruments work. Do they employ some sort of  radio frequency transmitted along the cable to locat the break ?"

    'Dont tell him Pike !'

    RS
  13. retiredsparks

    retiredsparks Member

    OP
    Use a metal detector.........
    RS

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