Ok to share a trench with other services?

[cornburn]

On a job we're going to need to bring our SWA underground for part of the install, and the main contractor is digging one big trench hoping to put gas, our SWA and mains water in. Not something I've done before sharing the trench with other services, can anyone see a problem with this other than there's going to be several lots of warning tape buried in the ground for each service?

Cheers

 

[Amp David]

Would of thought that services will have to be distanced appart from each other TBH. They never seem to be in the same trenches in the street

 

[KINKY]

528.3 says you can, but there are conditions to this

 

[cornburn]

Thanks, regs just seem to say as long as it's not "too" close, in other words anyone having to dig down for the others at a later date shouldn't have to interfere with the swa to get at the other pipes. I guess as it's mechanically protected too, as long as it's to the side as far as possible then that seems to meet requirements. Will tuck it at the far side of the trench. Cheers

 

[martysparky]

Reg: 528.3.5 states Where an electrical service is in close proximity to one or more non-electrical service/s, both the following conditions shall be met.
1. shall be suitably protected against hazards likely to arise from the presence of the other service.
2. Fault protection shall be afforded in accordance with the requirements of section 411, non electrical metallic services being considered as extraneous conductive parts.

 

[cornburn]

Yep, I've read that but can't see what hazards the other services (gas and water) could present when it's all buried though, those regs seem to be covering other situations, were pipes could leak in a wall cavity for example. When it's all sealed stuff and buried in the ground there's no additional danger as far as I can see. The SWA is protected from the elements anyway. What do you think?

 

[martysparky]

The thing that made me wonder was //non electrical metallic services being considered as extraneous conductive parts//.

but the they will be both surrounded by earth so not entirely sure what to think.

I'd ask the question too so watching with interest.

 

[pennywise]

I wouldn't be to worried about it personally, as long as there all down at the right depth and warning tape is present etc.

 

[malcolmsanford]

Reg: 528.3.5

Is there a lift in that trench as well ? ..............sorry just being silly

 

[cornburn]

Yes there's a small goblin lift to the underworld but cable won't be running down the shaft so it's ok. I'll go along with it then, push for a 600mm trench and just tape up as usual with it as far from the gas as possible. Can't see there's much more of an option really and if we're all struggling to find an issue with it there probably isn't one! Might give the good old NIC helpline a call in the morn see if they have anything useful to input

 

[MNR]

If you are sure it is far enough away not to effect the other, what is the difference in one trench or two trenches running parallel by the time it is filled in or am I missing something?

 

[cornburn]

I suppose so, I can't see how the other services could affect it at all so will chuck it in as planned and just make sure nothing's touching