Regulations re buried loop connections 1980

[TonyNorton]

Hi,

The electricity supply to our bungalow, which was built in 1981, is via a 'loop' connection from the fusehead in the property next door, to our fusehead.

Part of this loop, after leaving next door's property, runs diagonally across our front lawn, at depth of only 250mm (10"), goes under the pavement in front of the house at the same depth where it exits our property, from where, according to the electricity board's tracing equipment, it runs along underneath the pavement and then under our drive to our fusehead.

Can anyone tell me please, what was the regulation minimum depth at which this cable (Black, LV, 12mm O/dia), should have been buried, at that time? 10" is only one spade depth and, as the lawn is an area containing flower beds, so is quite likely to be dug over, I would have thought that 2 spade depths (0.6m/20") ought to have been the minmum.

The reason I ask is that we had a contractor in to grind away a smallish (15" dia) tree stump. The cable referred to, unbeknown to us, ran very close to this stump and got shredded, along with the stump. Result, no electricity supply for 5 hours and a very unhappy contractor He was very lucky that he wasn't using metal shafted hand tools to the job!

If anyone can quote me chapter and verse on whose regulations, specifically which regulation numbers, were in force at that time I would be very grateful.

I have tried to add pictures to my album but, whilst the system says "UPLOADING...", it patently obviously is not, uploading, that is. All images are a lot smaller than 1MB, so I can't see what the problem is there. Perhaps somebody shredded their 'loop' connection.

Tony Norton

 

[ricicle]

At present Eon's recommendation is that LV cables be buried at nominal 450mm. I'm not sure what the recommended depths were in 1980/1 but 10" does seem too shallow. Has the ground level changed in any way ?

That said our estate was built in 1999 and the street light cables are just laid in the sand below the block-paved paths !

 

[holmslaw]

..

 

[westie101]

There are not and never have been any regulations regarding the depth of buried main cables and services. The only document that made mention of depth was an NJUG (National Joint Utilities Group) document showing position and depth in a footpath, but in connection with ensuring we all (Utilities) had sufficient space to work on apparatus.

The approved method of avoiding damage and danger is contained in the H.S.E. Guidance note H.S.(G)47 "Avoidance of Danger from Underground Services" which any contractor who operates should have a copy of and be aware of it's contents.
The other means is via the legal requirement for DNOs to maintain records showing positions of services and making them available (the DNO I work for maintains a free website that contractors can access by registering (free).

It is worth noting that in H.S. (G)47, it specifically states that cables can be found at any depth and except from one case, firmly puts the onus on the client & contractor to avoid contact with services.

 

[ricicle]

There are not and never have been any regulations regarding the depth of buried main cables and services. The only document that made mention of depth was an NJUG (National Joint Utilities Group) document showing position and depth in a footpath, but in connection with ensuring we all (Utilities) had sufficient space to work on apparatus.

The approved method of avoiding damage and danger is contained in the H.S.E. Guidance note H.S.(G)47 "Avoidance of Danger from Underground Services" which any contractor who operates should have a copy of and be aware of it's contents.
The other means is via the legal requirement for DNOs to maintain records showing positions of services and making them available (the DNO I work for maintains a free website that contractors can access by registering (free).

It is worth noting that in H.S. (G)47, it specifically states that cables can be found at any depth and except from one case, firmly puts the onus on the client & contractor to avoid contact with services.

I find it hard to believe that the DNO could have laid an LV cable at 4" down in my mum's flower bed and it would be her fault if she hit it with her spade !

 

[JohnW2]

I find it hard to believe that the DNO could have laid an LV cable at 4" down in my mum's flower bed and it would be her fault if she hit it with her spade !

Quite so. For an industry which is (with good reason) almost drowned in safety-related regulations and CoPs (not the least relating to the removal of cutout fuses) it does, indeed, seem beyond belief!!

Kind Regards, John.

 

[bernardgreen]

It might be that the cable was laid by the builder who built the houses and the then DNO took his word that it was at a "safe" depth before connecting it to the fuse heads.

Both times I have had electricity supplies installed I laid the cable in place. 1980 a new build we were given the cable to lay in a trench ( we ducted it ) and the second time ( this year ) I supplied and laid duct into which the DNO's contractors installed the cable. The main network cable under the grass verge was about 15 inches below the surface.

 

[TonyNorton]

Hi Guys,

thanks for your responses.

Your level of knowledge is far in excess of mine, so I had difficulty with some of the abbreviations.

I sussed that CoP is "Code of Practice", I've downloaded HSG47, but I'm still stumped on "DNO".

If somebody could explain please.

Had another go at uploading images, but it still didn't work.

Tony N

 

[JohnW2]

....but I'm still stumped on "DNO".
If somebody could explain please.

Your DNO (Distribution Network Operator) are the folk who installed that supply cable, and repaired it when it got shredded.

Kind Regards, John.

 

[TonyNorton]

Thanks for that John.

Ours is the SEB, their guys were good as gold last night, worked for the best part of 3 hours in the ****ing rain, and wouldn't accept a tip at the end of it. Can't fault them. Not like the tossers who did the original installation.

Tony N

 

[ban-all-sheds]

Have you sorted out who's paying for it?

 

[TonyNorton]

At the moment the contractor thinks it's down to him. About £300 quids worth, and it's the third one he has hit this year.

I reckon it's about time he invested in cable locator.

As far as I'm concerned the SEB can chase me for as long as they like, they won't get a penny out of me!

Tony N

 

[westie101]

The major difficulty we have always had is the answer to the question what is the finished level.
Yeas back when doing new estates we always used to insist that the Kerb Race (the concrete foundation for the kerbs) was installed, this worked most of the time but it was not unknown for levels to change afterwards.

Or the builder would tell us that x amount of ground was to go on (especially in gardens) for it subsequently not to be done.

(lots of folk complain if they think a cable is shallow, few if it is too deep)

To suggest that we laid a cable shallow is frankly an insult, I have seen staff disciplined for not laying at our recommended depth!
On the day it was laid it would have been at the correct depth or planned to be, but like an MOT correct depth and position is only valid for that day.

To turn the question on it's head, BS7671 suggests that SWA should be laid in a particular way, how are you as an electrical contractor going to ensure it is at that depth and protected by tape for the life of the cable? You have signed to say it is, so in 15 years if an incident occurs would you accept responsibility if the tape had been moved or the depth altered?

Or should we all be required to dig all our cables up on a regular basis to check they are still at the correct depth.

No matter what the depth if a cable is damaged someone complains about the bill! If they all followed Health and Safety advice and followed safe excavation techniques there would be no issue.

But I will 95% guarantee that the contractor in the OP was not aware of the safe practices so had not gone to the trouble of obtaining plans or used a cable locating device to check the work area for the presence of cables.

Simple question if you have a supply of gas, electricity, water and a telephone and can see no overhead lines they will be underground! So why do so many folk not join the dots and think before they start digging (including flowerbeds)

 

[westie101]

At the moment the contractor thinks it's down to him. About £300 quids worth, and it's the third one he has hit this year.

I reckon it's about time he invested in cable locator.

Yes it is and after 3 incidents in a year he seriously needs to think about his safety plans.
P.S. a cable locator does NOT find every cable so proper training and other gear may be needed!

 

[JohnW2]

To suggest that we laid a cable shallow is frankly an insult, I have seen staff disciplined for not laying at our recommended depth!

There are not and never have been any regulations regarding the depth of buried main cables and services. ... It is worth noting that in H.S. (G)47, it specifically states that cables can be found at any depth and except from one case, firmly puts the onus on the client & contractor to avoid contact with services.

I'm a little confused.

Kind Regards, John.