Swa underground junction box

[James1]

Im looking to put a series of spike lights  around the house approx 12 units and wondering how best/cost effective it will be to have so many joints. The supply will need to be swa cable as it will be underground and need a 3 way junction box at each fitting. The lights  have a flex on them. I dont want juction boxs on show so intend to have them just underground (stone chip border between house and slabbed path)with the flex coming straigth down and into junction box. Can anyone say what junction boxs they would use for this and also if resin filled would be required.

Any help would be appreciated.

Thanks

[B52s]

IP65 rated PVC junction boxes would probably be suitable (no resin filler required).  I assume that you will be terminating the swa cables using appropriate swa glands and shrouds.  I'm a little concerned about the flex leads provided with the spike lights - what voltage will be passing through the flex to the spike lights?

Edited May 18, 2017 by B52s

[Nickfromwales]

I'd go with resin filled for anything subterranean TBH, as heavy rain could easily see these junctions inundated with rainwater.

You cant bring an exposed flexible cable up the wall I'm afraid. It'll need to be in a pvc conduit at least so it has a degree of mechanical protection beyond its PVC / PVC sheathing.

Do you have the lights already, and can you remove the supplied flex so you can replace it with SY Multiflex / similar armoured cable. ?

 

Oh, and welcome to the forum. . 

[Jeremy Harris]

Resin-filled for me, too, as any underground joint really needs to be better than IP68 (or have a specified set of IP68 test conditions); IP68 normally only has limited water resistance when immersed, and some water ingress is permissible, and that's not adequate for a buried junction that could be more or less permanently in water or wet ground.  IP65 is wholly unsafe for underground use, as it's only resistant to water jets, not any sort of immersion.

Edited May 19, 2017 by JSHarris

[James1]

No the lights are not purchased yet but the ones im looking at have a 2m flex on them. Just having another thought, do you think i would be better doing it all with 12v lighting instead. As the bulbs will all be low volt LED anyway. Im led to believe i would then not need swa cable after the transformer and just use a double insulated 2 core, easier to terminate at each junction box and can still be buried. There is a wider choice of jb's for cable  without needing to terminate the swa. Any cons going that way?

[PeterW]

12v is much better - can't see why you would want to use 230v unless it's very long runs. 

[Jeremy Harris]

I'd second just going for SELV, makes life a lot easier (and cheaper!).  I'd run a decent, immersion-rated, two core cable (something like H07RN-F, or perhaps H05RN-F/3182P "pond cable") inside a length of buried conduit.  You can then make off the tee junctions easily with pond cable junctions, like these: http://www.ebay.co.uk/itm/Waterproof-Power-Cable-Connector-Joint-Submersible-Water-Pond-3-Core-CE-IP68-/182124643664?var=&hash=item2a67798550:m:mgk4Egab0ithpw7FDF8uGTA which should fit the above cable OK.

Edited May 20, 2017 by JSHarris