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BS7870-3.11 DNO cable

Former Community Member
Former Community Member

New one on me from WPD.

New 45 kVA 3-ph service connection from existing OH distribution to be laid from pole to premise in asked for 2" rigid duct of our supply and burial.

Had to use my 75 mm mole in four pits to get under private drive and lawn so had to go quite deep to avoid mole rising. Dowsed for pipes and drains so no “incidents”…………………..

I was expecting 35 mm2 aluminium with copper wavecon but they used BS7870-3.11 cable that was 25 mm2 copper with a 25 mm2 fine wired outer and just slow spiral, not wavecon.

Consequently the outer diameter is just 23 mm and had I known, I would have used smaller duct and 55 mm mole to save going as deep as they only wanted 450 mm cover.

Apparently, no need for wavecon on standard service cable as can't take another service from it. 185 mm2 has to be used for two or more services which still has wavecon outer.

Regards

BOD

BS7870 Part 3, section 3.11 covers Cross-linked Polyethylene (XLPE) insulated combined neutral and earth copper wire concentric cables with a voltage rating of 0.6/1kV.

 

ConductorStranded (Class 2) plain annealed copper or solid (Class 1) aluminium
InsulationCross-linked Polyethylene (XLPE)
Bedding (for three phase cables)Polyvinyl Chloride (PVC) or synthetic tape bedding
Concentric neutral / earth conductorSingle layer of plain annealed copper wires
OutersheathPVC Type DMV 23
Parents
  • Former Community Member
    0 Former Community Member


     

    Does dowsing really work? I`ve always been very sceptical.

    I was also very sceptical ebee but I've really got into it lately. I can't get on with the traditional hazel twig nor the thin welding rods/coathangers but I tried some bespoke heavy forged rods and found them ok. However, my instrument of choice is just a simple, single 90 degree rod. I have to be in a fairly still air environment as strong gusts cause problems.

    Having said that, I still use my CAT (not my familiar, a black cat!) and Genny if I want to know the depth of a buried cable. When no one is watching, I'm going to have a go at divining the depth of a pipe/drain!

    Regards

    BOD

     

Reply
  • Former Community Member
    0 Former Community Member


     

    Does dowsing really work? I`ve always been very sceptical.

    I was also very sceptical ebee but I've really got into it lately. I can't get on with the traditional hazel twig nor the thin welding rods/coathangers but I tried some bespoke heavy forged rods and found them ok. However, my instrument of choice is just a simple, single 90 degree rod. I have to be in a fairly still air environment as strong gusts cause problems.

    Having said that, I still use my CAT (not my familiar, a black cat!) and Genny if I want to know the depth of a buried cable. When no one is watching, I'm going to have a go at divining the depth of a pipe/drain!

    Regards

    BOD

     

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