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Topic Title: Cost of re-routing a 33kV overhead line.
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Created On: 20 August 2013 03:16 PM
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 20 August 2013 03:16 PM
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AncientMariner

Posts: 505
Joined: 14 December 2004

Good Afternoon

With my County Councillor hat on, can anyone please give me a ball-park figure for the cost of increasing the height of a 33 kV overhead line?

Currently, the line is across a field, but there has been a couple of planning applications, both refused and one refusal upheld on appeal, to build some day rooms directly beneath the line. (These day rooms are to service a gypsy caravan site.)

As I see it, two wooden poles would have to be increased by, I guess 5 metres. And I also guess that the style of insulators on the poles eather side of the high span would also need to be modified - whether that would in turn require new higher poles there I don't know.

Anyway, all I am looking for is a rough figure of total costs.

The existing line has typical pole spacing and height for a 33 kV line over farmland with wooden poles.

Thanks.

Clive

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Clive S Carver GCGI IEng MIET
 20 August 2013 09:58 PM
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JonathanHill

Posts: 225
Joined: 09 September 2002

Clive,
Raising up by 5m isn't really practicable. Apart from the difficuties in getting adequately tall poles, the line will be an H&S obstacle during the entire building process, and a potential nightmare for subsequent maintenance.

I think the best solution will be to underground the line for a number of spans. This will probably involve establishing new terminal poles with stays at either end of the undergrounding. My guess for costs would be in the order of £25 - 30k, but you should speak to the lines owner, presumably the DNO.

It's possible that the permission for the route of the line may be as a Wayleave. These are usually subject to periodic (annual) renewals. If so, then this will probably allow for the landowner to request the line be removed and possibly offer to allow the line to be rerouted, whilst still on his land. If the permission is as an Easement, then this option wouldn't be possible, though some DNOs look kindly on undergroundings needed for H&S.

Good luck

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Jonno
 22 August 2013 08:04 AM
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statter

Posts: 124
Joined: 06 February 2013

If its a 33kv line then under grounding costs will prob be well into 6 figs even for just a couple of spans. Last time I looked joint kits were nearly 10k and then there is te cable, trenching, cable protection etc....
 23 August 2013 08:20 PM
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neilmcd84

Posts: 56
Joined: 02 June 2003

It's not a good idea to raise a line to build underneath. ESQCR requires 3m clearance from 11kV and 33kV lines to any structure, but there are additional requirements imposed by GS6 guidance that would mean the line would probably have to be isolated for the duration of the building work underneath - which can't happen at 33kV without putting huge additional risk on the network.
The only place I have ever raised a line instead of undergrounding has been at railway crossings where Network Rail have been installing new 25kV conductors. In those cases the overhead option has been chosen to avoid all the issues associated with directional drilling under a railway - settlement studies etc.
Therefore it looks like you will probably have to put it underground. Rough costs for 1 x 33kV circuit, 2 spans in unmade ground is probably £60k.
You could try the 'notice to quit' route if the line is only secured by a wayleave, but there is every chance it will have a servitude (or English equivalent if different) meaning the landowner can't get rid of it. Even if you go for a 'notice to quit' the DNO has up to three years to move their kit and they might choose to fight it if they think the result will deteriorate the performance of their network - as would be the case with a 2 span cable dip.
 23 August 2013 08:55 PM
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slittle

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Clive,

Which DNO ???


We had 6 spans of 11kv undergrounded plus a 800kva sub and intake for around £100k so I'd be tempted to agree with Neil's figure of £60K ish for 33kv


Stu
 24 August 2013 04:23 PM
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AncientMariner

Posts: 505
Joined: 14 December 2004

Scottish Power (SP Energy Systems) in the old MANWEB area.

Cheers!

Clive

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Clive S Carver GCGI IEng MIET
 31 August 2013 07:05 PM
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neilmcd84

Posts: 56
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You should contact Manweb for an indicative no obligation cost for this work. Their quote will cost you nothing, and will usually take 20-ish days to arrive. You can phone on 0845 270 0783 or email SPNCSouth@scottishpower.com. They will probably need a 1:500 drawing of your rough plans, so they can work out the extent of the diversion required and possible new cable routes.

It would also be worth thinking about whether you would be prepared to carry out the digging yourself to keep the costs down (trench 1.1m-ish deep, 500mm-ish wide, free of stones etc, light dusting of sand on the bottom, then cover the cables with sand after manweb's contractor pulls them in, install marker boards provided by manweb (1m long rubber) backfill and reinstate).
Other things to consider include land ownership - do you have a good relationship with the landowner/s? Will he / she sign off a wayleave / servitude without asking for a brown envelope under the table? Some landowners insist on lines being removed right up to the end of their land to avoid any stays coming down in the middle of their field and sterilising more land. This will obviously add cost.
The designer from manweb should be able to talk you through all these options. There is no harm in asking!
 27 February 2014 07:56 PM
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AncientMariner

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I sat in today on day 2 of the three day planning Public Inquiry for this site.

The Applicants Planning Advisor and Barrister were both happy to use the height of line above ground requirement to mean that you COULD build a single story building, with pitched roof, beneath a 33 kV o/h line, on the basis that the clearance only had to be above ground, ie above the existing soil level.

As an interested party, I am the County Councillor for the adjoining Council Ward, the Inspector accepted my thoughts and concerns to be given at the Inquiry.

However SP Energy Networks had already said in writing that they did not know the height of the o/h line (!!!) And they were happy, so long as their plant was safeguarded...........

The Applicant's Planning Advisor said there were no problems and said that he had a single o/h cable running past his own house.....

I hope the roofers have thick plastic safety helmets and rubber wellies.

Cheers!

Clive

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Clive S Carver GCGI IEng MIET
 27 February 2014 09:46 PM
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Zuiko

Posts: 521
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Originally posted by: AncientMariner
The Applicants Planning Advisor and Barrister were both happy to use the height of line above ground requirement to mean that you COULD build a single story building, with pitched roof, beneath a 33 kV o/h line, on the basis that the clearance only had to be above ground, ie above the existing soil level.


This was from an educated Barrister? The height above ground requirement is irrelevent here (the "basis" for his argument is as bizarre as it is wrong).

I suggest he reads British Standard BS EN 50423-1

Especially table 5.4.5.2

For bare conductors above the building:

Fire-resistant roof (> 15° pitch) = 3m
Fire-resistant roof (< 15° pitch) = 5m
Non-fire resistant roof and fire sensitive installations (fuel stations etc) = 10.6m




Bear in mind that the minimum safety distance for a 33 kV conductor is 0.8m; so if a tall person (2m) is standing on the roof they are perilously close the the safety distance, and within it if they raise their arms (which they could do if working).

Edited: 27 February 2014 at 10:06 PM by Zuiko
 27 February 2014 10:45 PM
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AncientMariner

Posts: 505
Joined: 14 December 2004

I don't know the height (above ground) of the o/h line, but the single story buildings (day rooms for a gypsy site) are approx. 4 metres high to apex of roof which is at an angle > 15°

The site is currently a pasture and the 33 kV is on wooden poles. Simple common sense says NO but what they come up with tomorrow (unfortunately I will be elsewhere) will make interesting reading when it comes out in around 6 weeks time.

Besides the buildings, there will be a 2 metre high soil bund (for noise reduction) also under the o/h line with a wooden fence on top.

There was talk of getting the line changed to an underground cable, but no one mentioned at whose cost...

Cheers!

Clive

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Clive S Carver GCGI IEng MIET
 28 February 2014 12:53 AM
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alancapon

Posts: 5745
Joined: 27 December 2005

Hi Clive,

Health & Safety Guidance GS6: Avoiding Danger from Overhead Power Lines recommends a vertical clearance of 3m and a horizontal distance of 10m, for non-competent people. Zuiko (and myself) as competent persons under our own DNOs requirements can work to lower safety distances.

I also attach a link to our Look Out - Look Up booklet.

Regards,

Alan.
 01 March 2014 10:25 PM
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slittle

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Joined: 22 November 2007

Let's face it, if they leave the 33kv line overhead and it's within arms reach then bearing in mind what it is crossing I'll have good money it won't be overhead for very long

In all seriousness it's got to be clearance from the roof to the line that matters ???? We almost had to move a pump control building a couple of years ago because it was nearly within "reach" of the 11kv that fed the new transformer for the building.


Stu
 17 March 2014 09:24 AM
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mikek

Posts: 39
Joined: 13 September 2001

Height above ground of the conductor is irrelevant. That's Reg 17 of the ESQCR. The relevant regulation is 18, and then you need to refer to ENA TS 43-8 and HS G6.

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mikek
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