Final circuit & DNO cable in same trench

[stummish]

Hi all bright sparks,

I've had a question from a client I couldn't answer on the spot. I've done some google research but can't find an answer to this;

Is there any reason the DNO cable and a final circuit be installed in the same trench? DNO cable will be in a duct, client wants the SWA dropped in next to the duct.

There's a new supply being installed from the roadside 25m down a private driveway (5 trees next to driveway so there will be a lot of roots etc) to the new cutout position, and they want up lighting on the trees. My client doesn't want to dig any more trenches than is absolutely necessary, so is there any reason i can't drop my SWA in the same trench as the DNO cable as it takes the same route. I can't find a reason in 7671 (maybe I'm being blind), and I can't find anything about it on google.

Personally id like a separate trench so the 2 cables never get confused in future, and if something ever did go wrong with the final circuit, the DNO cable wouldn't be affected. I'd like a lot of things, most of which i probably shouldn't do , but is this case is it an absolute NO!

Thanks in advance.

 

[Hellmooth]

Ask the DNO, wouldn't think they'd be to happy about it, no experience of it though!

 

[SparkyChick]

I would give the DNO a call and ask them the question as @Hellmooth has already suggested.

My personal view would be the same as yours for the same reasons.

 

[Wilko]

I've not asked, but I suspect DNO may not be happy to share.

 

[Taylortwocities]

It's a private trench on private land, where's the problem?

 

[PEG]

Hi,now this is something i have done. The DNO,if asked,may give all sorts of rules and stipulations,that goes out of the window,the second they get beyond the pavement.

If one is ducted,bearing in mind you could mole a duct or cable in,and it end up under/over round anything sub-terra,suitably stepped off,and taped,the world won't end.

I had a conversation with a Northwest Electric engineer,regarding this matter,and it went like this "Can i put my other services in that trench?" ..."No,there's rules mate,it makes things complicated...i can't OK that..."
Me "How about you come back to expose,or repair,next week,and there's 6 other ducts and cables in that trench?"

Him "Don't matter,then,it'll be just like every other job we excavate..."

Another duct or liner,would limit having to excavate around supply,if needed,but you will find discussions with the DNO are modelled on the "Fight Club" mantra...

 

[stummish]

Thanks for the replies so far,

I'm back on that site on Monday so I'll have a chat with all concerned then.

 

[driverman]

Why not put the DNO cable, which as you say will be in ducting into one corner of the trench. Customer's SWA cable and or ducting in the opposite corner of the trench. You could also clearly mark on marking tape which is which. I don't personally see a problem.