Electrical cable under ditch

[tommyt]

I have had a design from UK power networks for my electric connection today.

The nearest LV pole is on the verge (Country lane) 30m or so down the road and it terminates there. The last house it feeds is the neighbour. 10m further up the road is a 33kv HV pole with a transformer overhead feeding the 2 houses further up. Apparently the transformer would need upgrading to feed my house and quite costly and then mole under the ditch into our property. The 33kv line from the this pole goes into ground and crosses the ditch from the verge and is then buried inside our boundary and runs out along our hedge line but would need a substation built to tap off from it. 
 What they have suggested is that a new pole is erected in our garden and fed from the LV pole 30m away, crossing from the verge over the ditch at an angle and to our new pole. New stays would be needed on existing pole due to the new cable angle. A small tree would need removing also to allow this route as it is angled across.
The other option was a new pole on the verge in a straight line with last pole on run and then again mole a duct under the ditch but more cost. What I would like to know is the spec for crossing a ditch with the supply? Can It be done myself? 

What they have suggested Is fairly simple design but still costly and I need to save where I can.
What are my options? Can I dig a trench across the ditch and lay duct in for them to pull cable through to my temp kiosk?  We will be building a new culvert crossing soon as well so could it be incorporated in this? Water mains supply is also running along in the verge so will need to take a similar route across.
If it makes any difference IIRC the 33kv line was just trenched deep across the ditch and reinstated. 

 

[ProDave]

If multiple services will cross the ditch, your key is get the crossing for all services done in one go with ducts for all services installed.  This is what I did (though it was a road crossing) for water, electricity and telephone. 

 

Tip find out from Open Reach where your phone line will come in and provision for that as well if needed.

 

If the ditch is on the highway then officially you can't do it yourself, you need a contractor with a minor street works permit, and you may even need a road opening permit  from the council.

 

What I found was by requesting a quote from the utilities for my road crossing, and also a private contractor I could choose the cheapest.  In fact in my case the water gave the cheapest for the road crossing so they did it and with the trench open I dropped in the ducts for telephone and electricity.

 

You definitely can run a cable under a ditch.  Just up the road from me under a neighbours garden, there is an underground 33KV line from a nearby wind farm, and that passes under the burn.  I didn't see them actually do it so I don't know how deep and I don't know if they moled under, or dug a trench through the burn.

 

With my electricity connection, I had ended up with a duct all the way from the connection point to my meter box, so I opened up the connection pit myself, and got the electricity to re quote on the basis all they had to do was pull the cable through the duct and joint it in the pit that was already open.  That knocked about £1K off my electricity cost.

[ToughButterCup]

11 hours ago, tommyt said:

[...]
The other option was a new pole on the verge in a straight line with last pole on run and then again mole a duct under the ditch but more cost.

What I would like to know is the spec for crossing a ditch with the supply? Can It be done myself? 

[...]

 

I think you could ask the supplier for that specification.

Our supplier sends specificationstion to the applicant  as part of the standard application process.

[ProDave]

34 minutes ago, AnonymousBosch said:

 

I think you could ask the supplier for that specification.

Our supplier sends specificationstion to the applicant  as part of the standard application process.

I have seen them quote  the standard depths for under a road, under a path, under a garden, under agricultural land, but not under a watercourse.

[ToughButterCup]

4 minutes ago, ProDave said:

[...] but not under a watercourse.

 

missed that ... ?

But wouldn't the Utility designer need to take that into consideration anyway? I mention it because in my direct recent experience if they get the design wrong, then its their responsibility to put it right. 

[ProDave]

This is worth a read https://www.sepa.org.uk/media/151036/wat-sg-25.pdf

 

You will need to find the EA equivalent for England

 

Page 19 merely says "sufficiently deep"

 

Be aware a river bed is a fluid thing.  In a couple of places our burn has eroded the bed noticeably in the time we have been here, sufficient to expose 2 clay pipes underneath it that I did not know were there.  Not on our bit, so not an issue for me, this is just under the bit of the burn passing through the edge of a field before entering our garden.  It seems every time the burn is in spate, a bit more of the bed gets scoured away at this point.  So I would want a pipe quite deep down.

[tommyt]

Thanks both for those answers. Given me some more food for thought. I have emailed the surveyor to ask for the spec to go under the ditch.
Will be getting water surveyed soon so will see what they suggest. 

Phone pole is also terminated at neighbouring house but much closer to our plot so could easily go across at high level but again if I can get it in a duct at the same time as other services all the better. At the speed I’m getting things done round here though 6g internet will be out and I won’t need BT. 

[tommyt]

18 minutes ago, AnonymousBosch said:

 

missed that ... ?

But wouldn't the Utility designer need to take that into consideration anyway? I mention it because in my direct recent experience if they get the design wrong, then its their responsibility to put it right. 

 The surveyor mentioned it was a definitely a possibility but that they would mole it and that it would obviously cost more than cable straight across to a new pole so I discounted it without seeing the actual cost. 
 

I may try a quote from a private contractor to do all services and see what their ideas are. 

Edited January 11, 2020 by tommyt

[tommyt]

Quick update on this. I managed to get a vague answer from UKPN regarding going under a ditch, basically just quoting me the standard depth of 450mm for garden land or footway and then added “maybe just go a bit deeper just to be sure” 

 

I had also asked if I could have the new pole I need £955 or even just the extra cable stays that are apparently needed on the existing pole and that are quoted at £304! installed privately as I have a friend who runs a private contract company doing repairs for UKPN so has a Unimog with hiab and auger onboard and could do the whole job really, but I was told no due to the need for all new poles to be marked on records and labelled/numbered correctly. 
 

So I will now be going down a longer route, still needing to cross the ditch but in a different location but laying the duct myself and building a temp meter and supply box in a place where I can probably leave it as permanent. As many others on here seem to have done.