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So I am refurbishing a 50 metre long concrete path.

I am burying:

  • NYY cable run for water pump
  • NYY cable run for outbuilding
  • NYY cable run for lighting
  • 2 * PVC water pipes for water to and from pump

The outbuilding is already connected to electricity, so it's just a case of burying the cable, and the water pump is already in place. However I don't have lighting in place for the path, and I haven't really thought about it yet.

So my question is this sensible? Do I need to install some kind of junction boxes so it's easy to connect the cable up to subsequent lighting posts? (I have a second outbuilding that's not connected to electricity currently, I guess this might need a connection subsequently).

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In my opinion the best thing to do with "intention of future..." is empty conduit. Under NEC rules, 18" deep unless protected by various means (such as a concrete path on top) which alter the required burial depth. Your local rules may vary, since I also don't recognize "NYY" as a cable type I'm familiar with in North America.

Buried cable is making a bet that you guessed right. Conduit lets you guess right about where it goes, without concern about the actual wiring until you get to that point, and you can change it out later if need be, without having to dig the trench again.

I like to add at least one more conduit than I know what I'm using them for - conduit is cheap, trenches are expensive.

  • NYY is UV-stabilised PVC cable for outdoor use. Unarmored. We don't really have any rules (Indonesia), I just try not to do anything too stupid. I was planning to use conduit, but I guess there isn't really any advantage in adding the cable now. So you just add the conduit now, and then drill into the concrete at the point you want to add lighting to access the conduit? – thelawnet Dec 26 '16 at 23:10
  • I mean is there a significant advantage to leaving an empty conduit compared with just filling it with cable right away? – thelawnet Dec 27 '16 at 0:19
  • @thelawnet -- think of empty conduit like an empty expansion slot on your PC -- it's room for future growth – ThreePhaseEel Dec 27 '16 at 1:00
  • If you can figure out where the lights might be, adding junction boxes and conduit stubs to the concrete surface will save on a rather tricky drilling operation. If you can further think about what sort of lighting you'll have before pouring concrete you can either set mounting bolts for the light bases in the concrete at that time or use longer conduit stubs sticking up above the path surface if your lighting can mount directly to conduit. As for leaving it empty .vs. putting wire in, if you have not chosen the lights yet you might put in wire larger or smaller than you'll actually need. – Ecnerwal Dec 27 '16 at 16:25

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