External Lighting

[wonderdust]

I wish to install outdoor lighting around the perimeter of my driveway.

The lights ill be using will use low energy 16watt 2D bulbs.From the main power supply to the last light will be around 150 mts,most of the cableing will be underground in all there will be 12 lights.

My question is what size fuse will be needed at the main box and the size of cable to avoid voltage drop.

thanks in advance

andy

 

[securespark]

You could run it off a 3A fuse or breaker, using 2.5, and don't forget to use CW glands outside. And follow the rules about burying cables, ie 450mm down, sand & warning tape etc.. Look it up using search.

 

[comms]

12x fittings at 100w = 1200w I = 5.22Amp
swa 4mm over 150 meters gives the following
volt drop of 7.4 volt
3.2% volt drop
lighting load of 5.22 amp = 6amp mcb in c/u

 

[plugwash]

well firstly he said the lights were 2D low energy bulbs at only 16W each and based on that you would get away with 1mm or 1.5mm fine

however the things do have quite a high switch on current so larger sizes may be justified

if there is a possibility you may want a socket somewhere on your run then 10mm may be a good idea over that kind of distance but it will be a bit of a pain to terminate it

i tend to belive that small sizes of swa are a false economy when you consider the effort of laying them

i think i heared it said that for all sizes below 100mm the cost of laying exceeds the cost of the cable

 

[wonderdust]

Thanks for the replys just one more question

The bulb casing is the plastic round bulkhead type the problem will be as the swa is so thick how can i go about getting the main feed and then the next feed to the next light and so on through the bottom entry point as the cable will have to come up from the ground up a post to all the lamps

any ideas

ta Andy

 

[breezer]

use a t junction box, the centre being a separate feed to the light.

you could use plastic weatherproof boxes (including banjos) but it really depneds on the actual lamp fitting you use

 

[plugwash]

there are a few options

one option is to use resin joint kits and drill a small hole for a fex to the light. This option has the advantage of sginificantly reducing the number of ways the system can leak but may increase the cost somewhat

another option is to use a galanised tee conduit box but make sure it has a seal for the lid and that you screw th glands in tight also if you are using one of the larger sizes of cable you won't have much space to work in inside it

another option is to use a plastic adaptable but then you have to be quite carefull with the banjos for earthign teh armour and it will end up being quite a bulky soloution and possiblly leak prone

 

[Lectrician]

Use galv trouser boxes with gasget and lid. Terminate the armour into the bottom two, and leave the cable long enough to get right up into the light.

 

[breezer]

i was thinking of

obviously in galavanised (first pic i found) but your trouser box is better

 

[ban-all-sheds]

Wonderdust - I'd advise against conduit fittings.

These guys make the things you need: http://www.cable-connectors.co.uk/Pratley_Product_box.htm