Does outside buried conduit need sealing or a drain hole?

Discussion in 'Electricians' Talk' started by Pinkspark, Feb 11, 2024.

  1. Pinkspark

    Pinkspark New Member

    Hi guys, I have 2 lengths of buried conduit containing swa and external waterproof data cable. There are no drain holes in the conduit so it's liable to fill up with water. This shouldn't affect the cable but won't look great. Is it ok to blob some sealant in the ends? Or does it have to be special gel? I don't want to use the runny gel, it'll just flow into the conduit and require buckets of it. Does anyone have any recommendations?Thanks
  2. Wellwisher

    Wellwisher Well-Known Member

    Why did you use conduit? Not necessary for SWA or water proof data cable?

    As you have it use sealant.
  3. bright_Spark

    bright_Spark Screwfix Select

    SWA is not good just laid in a trench and backfilled although it is common to do so. by running it through conduit underground keeps it water tight provided both ends of the conduit are sealed. SWA is not actually waterproof as is commonly thought. The weak points of the water proofing is by using normal swa glands, outdoors external glands should be used,
    Ind spark likes this.
  4. Wellwisher

    Wellwisher Well-Known Member

    Can you provide a link to this?
  5. bright_Spark

    bright_Spark Screwfix Select

    OMG do I need to?
  6. bright_Spark

    bright_Spark Screwfix Select

  7. Wellwisher

    Wellwisher Well-Known Member

    The link I wanted was one that said SWA is not suitable for direct burial.
  8. Ind spark

    Ind spark Screwfix Select

  9. bright_Spark

    bright_Spark Screwfix Select

    OMG are you actually an electrician?
  10. bright_Spark

    bright_Spark Screwfix Select

  11. Bob Rathbone

    Bob Rathbone Screwfix Select

    Wow! I spent my apprenticeship burying this stuff in the ground, some sand and a marker tape, now you tell me that SWA is unsuitable for direct burial, someone better talk to the REC's they bury lots of the stuff. Now, let's get this straight, PVC SWA is waterproof to a few metres deep, the sheath is impervious to water and joints made with epoxy resin are also waterproof. You should avoid terminating SWA with glands of any type under water, the exposed armour must be protected from moisture, sometimes with a shroud if the risk is small or if the risk of moisture is high, a gland with an additional rubber packing is used. It is futile to try and seal against moisture ingress in a conduit system, a drain point should be provided at the lowest points of the conduit run.
    Coloumb likes this.
  12. Coloumb

    Coloumb Screwfix Select

    I thought it was XPLE that was bombproof and PVC SWA is only used for indoor stuff.
  13. bright_Spark

    bright_Spark Screwfix Select

  14. bright_Spark

    bright_Spark Screwfix Select

    No need to tell anyone this, it is common knowledge to those who know. SWA covered in sharp sand is ok in most circumstances but with our weather at the moment, we have gardens flooded all through the winter. Round my end it is like everyones gardens have a moat. SWA is not ok to be laid in a few meters of water, water resistant is the word not waterproof. Your comment of joints made of apoxy resin are waterproof too, may well be the reason I dig them up most days having to re do them, they dont last forever.
    Ind spark likes this.
  15. The Happy Builder

    The Happy Builder Screwfix Select

    A cable being exposed to moisture and occasionally getting wet is not the same as a cable constantly submerged in water, particularly if it’s in a buried water filled conduit that may have half a metre or more head of water pressure.

    The best option is to drain the water.
    bright_Spark and Ind spark like this.
  16. BuildingMad

    BuildingMad Screwfix Select

    40 years & counting my cables have been 3' down in clay soil.
  17. bright_Spark

    bright_Spark Screwfix Select

    have you done an ir test on it by any chance or do you mean it is still just working?
    The Happy Builder likes this.
  18. The Happy Builder

    The Happy Builder Screwfix Select

    bright_Spark likes this.
  19. And when the cables are installed like this with the armour not bonded across the isolators so totally unearthed.

    Attached Files:

  20. Astramax

    Astramax Super Member

    OMG, you are still actually a Screwfix Select member! :cool::cool:....:D...word on the street was you were being upgraded to Super Member. :rolleyes:
    arrow and Deleted member 34779 like this.

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