External lighting

[Paul Chick]

Hi guys,

Ive got a few outside lights to wire in next weekend and was wondering what sort of flex would be durable enough to go from the galv 'T' box upto the lights?
Im looping the lights round in armoured flex through 'T' boxes because i obviously cant make of those connections within the light fittings themselves due to space and looking crap.

Cheers,

Paul

 

[ackbarthestar]

True. But they had no choice but to bury them in stand alone planters. Horrible job because i had to physically climb into the planters to do some fiddly swa glands.

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One job about 18 months ago, I installed 6 of them in raised vegetable beds feeding LED IP rated ground lights, which were mounted into the sides. The client demanded that they were buried. I explained that when buried they disappear and then become susceptible to being damaged by a fork or spade. He called back about a month ago to be told "we hit one of the boxes with a spade, but we put a plastic bag over it" ! ........ 2 weeks later, I went round to have a look and found that the box had been split but no other damage to the glands and cable so was able to change the box within the hour.

 

[GLENNSPARK]

You tried social housing yet Glenn? Some of the stuff I've seen there still makes me shudder now

Not yet Trev but My boss does most of the work for this letting agents up there and most of the landlords in that area seem to use this agents......we get quite a bit of work out of it ...which is always good ....but the amount of these "tennants" that just dont give a FxxK.......the places are always filthy and the tennants often are as well.....a lot of evidence of power pinching n all at a lot of these places....we went in one place and i aint joking when i say there must have been about 30 odd dirty plates and loads of dirty cups n stuff.....the cooker would have set alight if you had turned it on...the amount of grease n fat on it....dog ends everywhare and piles and piles of filthy clothes all over....now i really resent having to wade through all this ---- when on a periodic and that cooker.....we were supposed to pull that thing out as there was a damaged ccu behind it.....well i wasn`t touching that thing....got the tennant to do it......makes me feel ikky sometimes after going in places like that....euggh......

 

[Engineer54]

im not burying the cables, where did i say that?

Sorry, must have assumed to were burying after reading simple simons post ...lol!!!

 

[GLENNSPARK]

Sorry, must have assumed to were burying after reading simple simons post ...lol!!!

would it still not be better to use plastic IP boxes though rather than the galv adaptable ones?.........

 

[Engineer54]

If the boxes are not going to be buried then filling them with 'gunk' is an extra unnecessary cost.

You don't need a 'jelly' compound even when they are buried, just a good IP rated terminal box with some petroleum jelly around the SWA glands and some WD40 on the terminal blocks.

Adaptable boxes filled with jelly do fail and because they are non-maintainable have to be be ripped out. Better not to bury them at all.

I'm sorry, but if you are burying a joint box they will need a filling compound if they are to have any chance of longevity!! Totally sealing any box IP rated or not, and you will induce condensation, and it won't take condensation long to start degrading connections, or metallic boxes. If you look at any IP rated enclosure you will Always find condensation seepage release locations, for drilling 4mm holes...

Bury any box and it needs a filling with a made for purpose compound so that condensation doesn't occur, end of!! We have installed literary hundreds of wisker boxed with the appropriate compound fill, and i've never yet known one to fail, ...not one!!! Ours are normally used on public pedestrian area lighting distribution systems, with interlinked block brick finish, that would cost a fortune to remove and replace, just to get to one of these boxes.

 

[GLENNSPARK]

I'm sorry, but if you are burying a joint box they will need a filling compound if they are to have any chance of longevity!! Totally sealing any box IP rated or not, and you will induce condensation, and it won't take condensation long to start degrading connections, or metallic boxes. If you look at any IP rated enclosure you will Always find condensation seepage release location for drilling 4mm holes...

Bury any box and it needs a filling with a made for purpose compound so that condensation doesn't occur, end of!! We have installed literary hundreds of wisker boxed with the appropriate compound fill, and i've never yet known one to fail, ...not one!!! Ours are normally used on public pedestrian area lighting distribution systems, with interlinked block brick finish, that would cost a fortune to remove and replace, just to get to one of these boxes.

we put some drive lights in the other week at this place and we used an IP box together with a compound filling as it was to be buried....my boss said it was the right thing to do here.......

 

[Engineer54]

would it still not be better to use plastic IP boxes though rather than the galv adaptable ones?.........

Sure it would, good quality one's. Conduit boxes even with gaskets fitted, are not exactly waterproof with just 2 fixing points for the lid, and the lid would need to be the galv cast type lid, not the thin galv sheet steel one's. Galv adaptable boxes fair a little better with gaskets fitted, but as far as i know would still at best only give an IP rating of around IP44...

 

[GLENNSPARK]

Sure it would, good quality one's. Conduit boxes even with gaskets fitted, are not exactly waterproof with just 2 fixing points for the lid, and the lid would need to be the galv cast type lid, not the thin galv sheet steel one's. Galv adaptable boxes fair a little better with gaskets fitted, but as far as i know would still at best only give an IP rating of around IP44...

yes and the thing is eng is i used to work in fabrications so i would look at the rigidity of something like this and its ability to withstand harsh environments .....such as being underground

 

[Engineer54]

yes and the thing is eng is i used to work in fabrications so i would look at the rigidity of something like this and its ability to withstand harsh environments .....such as being underground

I'd only use underground if protected, or assured of non-disturbance, never in a garden area where the ground is prone to digging activities etc...

 

[GLENNSPARK]

I'd only use underground if protected, or assured of non-disturbance, never in a garden area where the ground is prone to digging activities etc...

Yes. along comes "Mr fothargill" and his seeds.....busy with the fork n spade...lol.........

 

[ackbarthestar]

I'm sorry, but if you are burying a joint box they will need a filling compound if they are to have any chance of longevity!! Totally sealing any box IP rated or not, and you will induce condensation, and it won't take condensation long to start degrading connections, or metallic boxes. If you look at any IP rated enclosure you will Always find condensation seepage release locations, for drilling 4mm holes...

Bury any box and it needs a filling with a made for purpose compound so that condensation doesn't occur, end of!! We have installed literary hundreds of wisker boxed with the appropriate compound fill, and i've never yet known one to fail, ...not one!!! Ours are normally used on public pedestrian area lighting distribution systems, with interlinked block brick finish, that would cost a fortune to remove and replace, just to get to one of these boxes.

Interesting,
I've spent the last two years on one particular job digging up so called non-maintainable Gwiss boxes filled with 'jelly' .



All the terminations had corroded and failed. I found that water penetration had managed to penetrate between the compound and the insulation around the conductors.


The only maintainable joint is one that is not buried.



This one had a failed transformer.

I think the longest period of time some of these adaptable boxes had been in the ground was 4 years.

I always maintain that there is no such thing as a non-maintainable underground joint, unless its filled with resin and then you're f****d if it fails

 

[GLENNSPARK]

so what you say here then is a "scotchcast" type joint?.......

 

[Engineer54]

Interesting,
I've spent the last two years on one particular job digging up so called non-maintainable Gwiss boxes filled with 'jelly' .
View attachment 8733


All the terminations had corroded and failed. I found that water penetration had managed to penetrate between the compound and the insulation around the conductors.


The only maintainable joint is one that is not buried.

View attachment 8732

This one had a failed transformer.

I think the longest period of time some of these adaptable boxes had been in the ground was 4 years.

I always maintain that there is no such thing as a non-maintainable underground joint, unless its filled with resin and then you're f****d if it fails

To be honest, i've never used Gewiss boxes, underground or anywhere else, i just don't like them!!
None of those boxes look like they have had the glands terminated very well at all and they look like standard glands not IP 68 rated!! God knows what that filling compound is, nothing like what i've ever seen or used... What ever it is, it doesn't look, as if it's filled the boxes very well at all.

Looks to me like a p**s poor shambolic installation, and not one i'd be happy with. I can well imagine moisture getting to those connections etc!! But as i stated, use the right made for purpose boxes, the right connections (we crimp & shrink in all of ours) a good filling compound, and you should achieve a joint that is going to last for many years to come.

Oh, and we also use resin and heatshrink joints too for our road lighting distribution systems. Mainly for short Tee offs, across paths or whatever. Main lines to the Lamp Posts are ducted to ground pits at the side or in close proximity to the lamppost, (Sometimes joints are also located in these pits) that then enter the lamp post via small duct/conduit...

 

[ackbarthestar]

so what you say here then is a "scotchcast" type joint?.......

Resin filled joints are about the only type that appear to last. They go rock hard.

 

[Engineer54]

Resin filled joints are about the only type that appear to last. They go rock hard.

Nothing wrong with Resin jointing, just a bit OTT for use in a domestic garden to feed garden lights and the like!! lol!!