Best JB to bury - driveway lights

[richo106]

Hi

I am looking to install some driveway up lights on my new drive way, either side of my drive is grass/gravel (soft dig)

I have spoke to a couple sparky mates and they have done it with galv conduit t boxes, wagos and magic gel (or similar) with gaskets/box lids. SWA between the boxes and flex out to driveway. Then bury these boxes to the side of the driveway so they aren’t on show, I know not ideal but no where else to put JB’s

My question is, is there a better way to do this? What’s the best thing to bury? Wiska box? Galv conduit box?

Any advice/ information greatly appreciated

Many Thanks

 

[Pretty Mouth]

The requirements for buried cables don't change with voltage, see 522.8.10

There was an intended change for the 18th edition, exempting SELV cables from 522.8.10. Never made it into the final print though. The page on the IET site seems to be gone now, but I saved a copy. I think it would have been a good thing.

 

[davesparks]

There was an intended change for the 18th edition, exempting SELV cables from 522.8.10. Never made it into the final print though. The page on the IET site seems to be gone now, but I saved a copy. I think it would have been a good thing.

Why would it be a good thing?

Underground cables are all exposed to the same risk of damage regardless of voltage.

Yes the risk to a person from electric shock is reduced with ELV, but that is only one of the considerations when burying cables.

 

[mainline]

There was an intended change for the 18th edition, exempting SELV cables from 522.8.10. Never made it into the final print though. The page on the IET site seems to be gone now, but I saved a copy. I think it would have been a good thing.

Selection and erection of wiring systems - Chapter 52 - Wiring Regulations Information

Chapter 52 Selection and erection of wiring systems Regulation 521.11.201 which give requirements for the methods of support of wiring systems in escape routes, has been replaced by a new Regulation 521.10.202. This is a significant change. Regulation 521.10.202 requires cables to be adequately...

www.wiring-regulations.co.uk

 

[mainline]

Why would it be a good thing?

Underground cables are all exposed to the same risk of damage regardless of voltage.

Yes the risk to a person from electric shock is reduced with ELV, but that is only one of the considerations when burying cables.

It is blatantly obvious that ELV is far safer than LV that's a fact, although you did say some pets can be killed by 12v, but you didn't reply when i asked what sort of pet ? So I can only guess it to be some sort of slug, must be a long day taking one for a walk )

There are ready-made hubs and joint boxes for ELV which make especially for non-buried cables a lot easier to install and maintain.

There is also the nuisance tripping aspect of ELV to take into account compared to a mains supply, especially with a failure of a rcd.

There maybe the same risk of damage to the cables, but the effects of ELV are far less likely to cause any drama compared to mains derived ones.

 

[Pretty Mouth]

Why would it be a good thing?

Underground cables are all exposed to the same risk of damage regardless of voltage.

Yes the risk to a person from electric shock is reduced with ELV, but that is only one of the considerations when burying cables.

Firstly, cables buried at pretty much any reasonable depth can be damaged. I have personally dug by hand foundations to a depth of 6ft.

Getting the cables deep enough to 'comply' with 52.8.10 is labour intensive, and often impossible. In my experience, for garden lighting and so on, they're rarely installed more than a few inches down. Basically, it's a regulation that gets ignored because it's unrealistic to achieve.

Allowing SELV cables to be run at any depth gives a negligible shock risk should they be damaged, does not cause tripping further upstream, and, in my experience, cables such as H07RNF are much easier to repair than SWA.

The regs permit a similar exception for selv cables run <50mm deep in walls, through walls constructed of metal parts, and where concealed below floors/ceilings. To me, it seems sensible to allow similar for cables buried in th ground