Ground lighting in garden

[ElectricDunc]

I've been asked to price for a job which involves putting some halogen spike lights in a garden. Usually if i was doing this i would select extra low voltage lighting which just needs a bit of conduit and extra low voltage flex to each light. Always nice and simple as you don't need to worry about the shock risk at 12V. Unfortunately the customer has already purchased the lights and they are all mains voltage GU10 so i'll likely have to use armoured cable which will have to be buried between the fence and the lights.

I'm looking at using these boxes (link) which i intend to run my armoured cables to, then use IP68 stuffing glands to connect the flying leads from the spike lights in to the joint box. The whole thing can then be buried under the soil with warning tape over all buried cables. My big concern though is firstly ingress of moisture in to the box, secondly fern and fauna and thirdly that the joints aren't going to be easily accessible in the event of a fault. The biggest problem is making it look pretty but still meet regs.

Any thoughts on the subject or even recommendations from how you've done it previously would be greatly appreciated.[/url]

 

[holmslaw]

..

 

[ban-all-sheds]

I've been asked to price for a job which involves putting some halogen spike lights in a garden. Usually if i was doing this i would select low voltage lighting which just needs a bit of conduit and low voltage flex to each light. Always nice and simple as you don't need to worry about the shock risk at 12V. Unfortunately the customer has already purchased the lights and they are all mains voltage GU10 so i'll likely have to use armoured cable which will have to be buried between the fence and the lights.

The IEC definitions of voltage bands are:

• Extra Low Voltage: AC below 50V and DC below 120V
• Low Voltage: 50 - 1000V AC or 120 - 1500V DC
• Medium voltage: 1kV - 35kV
• High voltage: 35kV - 230kV
• Extra-high voltage: >230kV

This is not some pedantic technical point - you should get it right for the benefit of the less knowledgeable who visit this site, for if they start getting involved in doing their own electrical work, and start learning about regulations etc, they'll come across references to "Low Voltage", and it'll be no good them thinking that that means 12V...

 

[ElectricDunc]

Point well made BAS and changed first post accordingly. Basic college stuff the voltage bands but it's too easy to slip in to bad habits not using the terminology correctly.

If i was to resin up these joints then what would be the best way to secure the flying lead from the light in to my resin joint with the SWA. The resin joints available for SWA aren't really designed for a piece of flex and i would envisage it being all too easy to pull it out before the joints have cured properly.

 

[ColJack]

you shouldn't resin fill JB's with screw terminals.. they need to be accessible for I&T also, so you can't bury them..

if you insist on burial and resin filling, then your only options is cold pour resin joints..

your other option is to run an armoured to each light individually and terminate in the light..

why do they have a "flex" if they are ground spike mains lights..
..

 

[electronicsuk]

If i was to resin up these joints then what would be the best way to secure the flying lead from the light in to my resin joint with the SWA. The resin joints available for SWA aren't really designed for a piece of flex and i would envisage it being all too easy to pull it out before the joints have cured properly.

You can still get resin underground joint kits that will take glands > http://www.tlc-direct.co.uk/Main_Index/Cable_Accessories_Index/Cable_Joints_1/index.html. The manufacturer states they do not need to be compound filled, but I don't see why you couldn't.

The problem with any such installation is always going to be making the short length of unprotected flex conform. Short of taking SWA direct to the fitting, which is near impossible on small fixtures, there's not a lot that can be sensibly done.

EDIT: OK, completely ignore me. Having seen these joint kits in the TLC catalogue before I think I have got the wrong impression regarding glands. It appears that they are simply sleeves with a compression joint to keep the continuity on armoured cable. That'll teach me to comment on things I haven't actually used before

 

[Zambezi]

This is a topic I also struggle with because the customer does not want to see any wires or junction boxes, you want them to be accessible etc.
Those junction boxes look pretty good, compared to the ones that were used on the last job I was on (repair, not install) where I had to dig out all the junction boxes to drain the water out of them (they were rated at IP68) and dry them out! Around the water feature they had run the 230V flex, from the pumps, under the turf for a couple of feet before they went underground to the junction boxes!! The gardener went mental when I showed him the cables buried under the turf, he was aerating the lawn the week before
Some people should not be allowed to go anywhere near lekky!

 

[ElectricDunc]

why do they have a "flex" if they are ground spike mains lights..
..

Because they're piddly little lights rather then a sizable architectural light. Making an SWA off directly in to the light would be impossible hence the reason for jointing the cable. My only other option (and i don't think it's a particularly good one) would be to bury conduit up to the light and hope the tail from the light is long enough to reach the fence. This is what i'm expected to install - Oddysey Ground Spike.

 

[ban-all-sheds]

I would have thought that a resin-filled 3-way T joint would do the job - the cables from the lights are 2m long, so you'll be able to get down to a suitable depth.

If you're worried about the luminaire flex pulling out then put a couple of cable ties around it inside the box - once the resin has set around those I can't see it budging.

 

[ElectricDunc]

Looks like i'll be having fun with the resin joints then. I'll see about running the main SWA runs along the fence at low level then teeing off an accessible joint on the fence to a resin Y joint which i can then make both lights off in to. The garden doesn't get dug up much but the cables need to be in fairly deep to ensure they don't get forked up! What method would you recommend for joining the flex to the SWA? As it's inaccessable it has to be some form of crimped or soldered joint. Do you think i'll get a good enough connection if i use barrel crimps (assuming there will be 1x1.5mm and 2x0.75mm wires in it.

I assume your talking about these sort of resin joints BAS - link

 

[ColJack]

that's the one, but that's more of a Y than a T...

 

[sparkybird]

I dunno if this would help, but Wiska do a jelly like compound which they SAY can be used to fill their boxes and makes then waterproof (for going in the ground they say). If you needed to get to the terminations in the future, the compound can be easily removed and replaced.

I pointed out that when set, the stuff looks like 'chicken fillets' which had the girls on the trade counter laffing their heads off, and the bloke scratching his!

here's the link

http://www.wiska.de/eng/270,combi-ip-68-set.html

SB

although saying all that, I don't think I'd ever use them, feels wrong to put connections underground and many the hour I've spent trying to find them on (other people's) installations when they go t*ts up and trip the rcd

 

[ColJack]

that's false advertising you know..

the "chicken fillets", not the WP JB..

you get a girl home and then it's like.." hang on, where did they go ? "..

 

[ban-all-sheds]

I pointed out that when set, the stuff looks like 'chicken fillets' which had the girls on the trade counter laffing their heads off, and the bloke scratching his!

So you aren't Louise on the Ultimate Handyman forum then.....