MV Cable laying

[joseanmendia]

Hello, I need to know how is the typical section of buried cables in UK, I need a picture, or a drawing or a link where I can find this enquiry, because I am working in a project for this country and I am from Spain and I do not know if it is like in Spain or different.

Thanks

 

[Lectrician]

well, guide is an 18 inch trench, bottom filled with a couple inches of sand, then cable, then a couple of inches of sand, then about 6-8inches of back fill, then warning tape, then remaining back fill.

 

[fubar]

Do you mean warnings for buried cables, or cable colours, or identifying services?

The main specification is "BS7671: 2001 Requirements for Electrical Installations", available from the IEE or from BSi.

There are specific standards for the various details of buried cables.
The National Joint Utilities Group (NJUG) publication number 4 covers the colours of ducts, pipes and marker/warning tapes. Generally the duct is black (perhaps with orange bands) or orange with marker tape above the duct or able run. The marker tape is yellow with black legend:

We are currently in the process of moving cable core colours to the european harmonised colours. If this is what you mean, please search this forum for "harmonised colours" or post a reply for a more detailed response.

 

[ban-all-sheds]

I don't think that's what he was asking.

The title of the topic is MV Cable Laying, and the info sought is "typical section of buried cables in UK".

MV is 1kV - 33kV (IEC) or 1kV - 11kV (UK traditional)

So surely what he's looking for are cross-sectional diagrams of the types of buried cables used for up to 11kV or 33kV - these sorts of things:

No?

joseanmendia - on the basis that ye cannae change the laws of physics, an underground cable carrying tens of thousands of volts would need to have the same characteristics here as in Spain.

It is a shame that we no longer have a single company responsible for generating and distributing electricity - I'm sure the old CEGB could have helped you.

All I can suggest is that you contact makers of cables (e.g. Raychem, Pirelli, 3M) to see what they can give you.

Also, could someone post the details of the website that has links to all of the DNOs? I'm sure that at least one of them must have some eductation resources of use...

 

[fubar]

So surely what he's looking for are cross-sectional diagrams of the types of buried cables used for up to 11kV or 33kV

Makes sense (now!)

Also, could someone post the details of the website that has links to all of the DNOs?

I don't know of any that are up to date. You'll need to cross-reference these three:

http://www.electricity.org.uk/default.asp?action=article&ID=153
http://www.energynetworks.org/
http://www.energylinx.co.uk/distribution.html

 

[Lectrician]

I took MV to mean mains voltage, not medium voltage.....this is not the place to ask if your laying or jointing cables for the 11, 33 or upwards voltage ranges.

 

[AdamW]

Don't you have to be specially certified and insured for work with MV? In which case anyone who is working with this should be pretty certain of it already?

I know you can't change the laws of physics, but perhaps there are different requirements on armouring, insulation rating etc? Maybe there is a greater range of similar cables in one country compared to another, where the differences aren't quite clear?

What are the implications for Jose if he does the job, then the inspector has a problem with it?

Jose, I think you need to explain what it is you will be doing. There may be regulations that need to be followed, and you might even find that it isn't worth the risk for you to do it.

 

[joseanmendia]

Well, we are doing a Project Management in Cardiff. I have 33 kV cables, and for example Iberdrola (one of the electrical companies in Spain) have standards trenchs and they give its drawings. And in this case, in Spain (33 kV buried cables) the trench more or less is similar like Lectrician said, whit sand, warning tape... So I´m looking for is this trench's drawing in UK.

One thing for ban-all-sheds more or less the cables have the same characteristics in UK as in Spain but here are more kind of cables, for example in UK you have 6,6/11 kV and 19/33 kV, we for Medium Voltage have for example 26/45 kV.

I have BS 7671, but it´s only for low voltage.

In any case, thank you very much for your help whit my inquiry.

Kindest regards

Josean

 

[fubar]

I have BS 7671, but it´s only for low voltage.

I'd start with the Electricity Safety, Quality and Continuity Regulations 2002 and go from there. Regulation 14(2) looks like a good place to start.

Also, try contacting the Distribution Network Operatrs for information, by following the links above and the Local Authorities for their specific requirements.

 

[joseanmendia]

The electrical company is National Grid Transco (NGT)

 

[dw3101]

My dad is an electrical design consultant for a REC deals with large 100+MW installations up to 132kv

If you need something specific answering, drop me a mail and ill get you some answers.

I also think they quote for work for free?? (I know it has to be over 1million GBP to go to him though) but I can get answers to pretty much anything to do with LV / HV Distribution.

David
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Moderator

email address removed, these can be seen in your profile

 

[ban-all-sheds]

The electrical company is National Grid Transco (NGT)

Surely they have their own set of well-defined standards to which all contractors must work?

 

[Lectrician]

sounds dodgy to me. Onyle time i have worked near this stuff was on an airforce bace, they had an 11,000 ring - my boss did the spec and testing.

Not a task to be asking advice for on here.

 

[ban-all-sheds]

Where's BR when you need him....