SWA long run

[monkeyhanger]

A new build bungalow is 180m from the meter position (single phase meter in hut at the side of the road). There are 2x SWA from meter to a join next to the bungalow, where the supply then enters an external meter cupboard in 25mm SWA (new colours).

The two cables from the meter to the join are 1x 6mm 2C and 1x 16mm 2C (Red & black).

When I first entered site the building was already constructed, and that supply arrangement already present.
I have been to second fix, the builder was *sure* that the supply install had been done by a proper local firm (wont name here). After inspection it is evident that this isnt the case as there were no glands on any cable ends, no fused isolator or RCD or earth rod anywhere.

There is a static caravan and stables also on the site, which appear to be fed via the 6mm and 16mm SWAs from a join *somewhere* underground.

I have already been paid for 1st and 2nd fix, and stated that I wouldn't sign the job off unless the supply was adequate.

I have installed a 60A switch fused isolator and 100mA S type RCD & rod at the origin as a quick improvement to the situation and managed to gland the cables, however the cable run is obviously too far for 6 & 16 mm cables.

What would be the best way to proceed? To work out a suitable cabling arrangement from meter or to get the electric board to move the meter position to the bungalow?

 

[Guest123]

It would be 'easier' for everyone if the intake was re-located next to the bungalow albeit probably more expensive.

Whilst they were at it you could inquire wether or not a PME connection was available also.


If this isn't a viable cost effective option you'd need one mother of a trench and a nice new distribution cable from the intake to the bungalow by the sounds of it.

 

[i=p/u]

50mm 2 at probably 5er per meter

 

[Engineer54]

It is ''Expressly Forbidden'', to have a parallel supply with two different conductor sizes!!
I could go on and say a lot more, ...But the bottom line is, ...that as you have described to us, ....your supply to your bungalow is ''NOT'' Compliant ....Full Stop!!

 

[Knobhead]

Time to get the pick and shovel out.

With that length of run you’ll be putting some joints in unless you’ve got some heavy gear to handle the cable drum. 200m of 35mm 3 core = .42Tonne, 50mm 3 core = .63Tonne.

 

[i=p/u]

mini digger 130 a day

 

[Engineer54]

From what i can see from your OP, this supply to the bungalow that is too small for the length of run, it is also supplying other loads too. But more importantly it's totally non compliant for any of the loads it's feeding!!

If i were you, i'd contact the DNO and see what they have to say about it.

This is one installation that is just waiting for a disaster to happen, ...Then all that horse crap from the stables will be hitting the fan, and will be sticking to anybody involved in that cable(s) installation, ...big time!! lol!!

 

[monkeyhanger]

Ok thanks for advice.
Just to make it clear though, I haven't installed any of the SWA that is currently there.

 

[Engineer54]

Ok thanks for advice.
Just to make it clear though, I haven't installed any of the SWA that is currently there.

You made that point clear mate, in your OP. AS you stated refuse to issue any cert's until YOU are happy with the whole installation, including that sub-main fiasco supplying your installation.

Has anyone energised that sub-main by the way?? If they have, check the volt drop and Zdb and see what you get. ....But then disown it and stick to your professional guns. As i say i would get the DNO involved if this is being supplied at there metering location...

 

[Knobhead]

To be honest on this occasion I think the DNO may even be the cheaper option by the time the trench is dug and the cable pulled in.
There is the added advantage of if things go belly up it’s their problem.

 

[Rockingit]

To be honest on this occasion I think the DNO may even be the cheaper option by the time the trench is dug and the cable pulled in.
There is the added advantage of if things go belly up it’s their problem.

Completely agree - have seen DNO's turn up with three wagons, six blokes, lay many metres of cable and charge less for the whole job than I could have bought the cable for!

If you dig / arrange the trench I'm sure they'll happily oblige, you get much better loop figures and know the job's a good'un.

 

[Knobhead]

and know the job's a good'un.

Oh come on, that’s a bit of a rash statement. But as I said if it does ***k up it’s their problem.

:rofl:

 

[drew35]

I agree, DNO. Can they use a mole over that distance to save digging? I've seen them do it enough times over a short distance.

 

[Rockingit]

Oh come on, that’s a bit of a rash statement. But as I said if it does ***k up it’s their problem.

:rofl:

Rash??! Back to the docs for me again, then.

 

[monkeyhanger]

I phoned the DNO (NEDL) who wouldn't comment at all. I got passed on to someone who told me the website address to get a form to apply to move the meter.

 

[Engineer54]

This site's distribution system sounds like a complete Pig's Ear. It just has to be a DIY set-up. I can't see any Electrical Contractor installing such a system, Nor any qualified electrician come to that. I suppose i can't talk for some of these 17th only DI's, but even they should know better!! If our OP sticks to his guns and refuses issuing any cert's based on this potentially dangerous distribution sub-main, then something will get done about it. It's going to get a might expensive for someone down the line on this one!! lol!!

 

[Welchyboy]

so just doin a quick few calcs....35mm swa over 180m at 60A ib = 13.5V VD at end of cable
50mm = 10v VD
70mm = 6.8v VD
95mm = 4.9v VD

And thats just to the bungalow without the final circuits or the stables supplies, so the lighting circuits are never goin to comply with allowed voltage drop??

how would you overcome this situation??

surely only the distributor could resolve this issue?

 

[Engineer54]

so just doin a quick few calcs....35mm swa over 180m at 60A ib = 13.5V VD at end of cable
50mm = 10v VD
70mm = 6.8v VD
95mm = 4.9v VD

And thats just to the bungalow without the final circuits or the stables supplies, so the lighting circuits are never goin to comply with allowed voltage drop??

how would you overcome this situation??

surely only the distributor could resolve this issue?

Separately fused sub-main distribution circuits!!!

It doesn't comply in several areas, not just on the volt drop. As you say, this mixed size run of parallel cables is feeding at least 2 other installations on this site, so they won't comply either!!

 

[lamb]

Either way, the customer would have to run a larger cable. Either pay the DNO or an electrical contractor to do the work.
Alternatively the DNO could alter the medium voltage network and provide a pole mounted sub adjacent to the property, though for a run of only 180m this would probably not be cost effective.
I have done one of these jobs before, with a large property, driveway was a few hundred meters long. DNO installed supply to a kiosk on property boundary, and we ran 185mm SWA in a trench along the driveway. Either end was terminated in a poured resin joint underground and spliced onto 25mm SWA for ease of termination in house/kiosk.

 

[Welchyboy]

Either way, the customer would have to run a larger cable. Either pay the DNO or an electrical contractor to do the work.
Alternatively the DNO could alter the medium voltage network and provide a pole mounted sub adjacent to the property, though for a run of only 180m this would probably not be cost effective.
I have done one of these jobs before, with a large property, driveway was a few hundred meters long. DNO installed supply to a kiosk on property boundary, and we ran 185mm SWA in a trench along the driveway. Either end was terminated in a poured resin joint underground and spliced onto 25mm SWA for ease of termination in house/kiosk.

185mmm SWA in trench 200m ££££££££££££££££££££££££££££££££££!