New supply

[dingodeano]

This is true, but I really can't see it costing as much as 1km of 70mm SWA + 35mm CPC (or 3c 70mm)

I could. I imagine just for a crew to dig up and repair a cable must cost £££
I was involved in a similar job last year. The transformer and pole was on the land (a small holding about 1/2. Acre ) to drop down and install a 100a PME cost 7k. Approx 20m from pole to cutout.
I would be happy to be proved wrong though.

 

[RF Lighting]

I get feeling that network are not keen putting a cable onto land which potentially could be ploughed.

Unlikely, they would just need to ensure it is laid deeper than 1m which is the recommended depth for agricultural land (and agreed with the NFU)

Would the network connect to a cable laid at their spec? In other words could a 1000m of split con or whatever you chaps use be laid and the service be installed at point of utilisation ? What I'm asking is could the cost of work be negotiated and cost met by customer under guidance from network?

As good as the network chaps are, ye canny change the laws of physics

It doesn't matter which side of the supply the cutout is, you need to eiter use stonking great big cable, or run the supply at HV and step the voltage down locally.

 

[mfarrow]

No, but I can offer you a copper and iron one.

I can offer two.

Transform up to the safest low voltage you can. Historically this is 650V, and I'd suggest an earthed centre-tap on the secondary of the step-up Tx to provide +/- 325V and run 2c SWA down to the other end of the field, where you can install your step-down with TN-S secondary.

 

[westie101]

Would the network connect to a cable laid at their spec? In other words could a 1000m of split con or whatever you chaps use be laid and the service be installed at point of utilisation ? What I'm asking is could the cost of work be negotiated and cost met by customer under guidance from network?

That would be up to them, but at that sort of length at LV it is going to be difficult to adequately protect the cable (fuse) in case of fault and obviously volt drop is an issue.

I have seen one case where we bunched 2 cores for live and one core & sheath for neutral (PME). It worked but remains a difficult piece of non-standard network.
I would guess as well that the DNO would be looking to installing their "standard supply capacity" which would be between 60 & 100 A. This would then make it financially impracticable at LV

 

[dingodeano]

So how would the supply be put nearer outbuilding? Surely the nearest transformer is Being used? I just thought maybe supply network regs had some 'silver bullet solution' that could be applied !!!!

 

[westie101]

I would assume they have discussed it with probable costs already with the customer and he has "chosen" this solution as the lowest cost option from the DNO. No doubt thinking that a bit of SWA will be fine from the supply to the building (seen this before)

The DNO solution I would guess included HV cable or O?H line with a transformer at the end

 

[mfarrow]

I just thought maybe supply network regs had some 'silver bullet solution'

Split phase?

 

[dingodeano]

I see. Reading between the lines he is (quite rightly so) looking for the cheapest option. With the network dropping on the boundary and a possible SWA 1km run looking his cheapest.
I thought it a little odd him saying he didn't know the exact distance when he rang me. As I'm sure if I owned some land I would know how much was there.
I haven't much experience with step up transformers. Maybe worth looking into as a possible solution.

 

[westie101]

I haven't much experience with step up transformers. Maybe worth looking into as a possible solution.

Which gets into a whole different world of electrical protection, earthing, HV operating which is a lot different to LV isolation.

 

[dingodeano]

None of which I have had any training or experience on.

 

[ban-all-sheds]

No, but I can offer you a copper and iron one.

I can offer two.

Yes - it would be best to use them in a pair, otherwise it would get very interesting at the destination, particularly if you've stepped up to MV. Or HV as Westie calls it.

Is only going up to 650V worth the effort?

 

[davelx]

Might it be possible for the DNO to run in a new supply overhead at 11Kv to a pole & Xformer close to the stable building? Must be cheaper than going underground. You see that all over the place in Kent.

 

[jamesmcbride]

I would have thought so too... surly just digging a trench 1m deep and 1km long is going to cost a few thousand!

 

[mfarrow]

Is only going up to 650V worth the effort?

It was when we went 2km, and in fairness it is nearly 3x the normal line voltage, which is saving you a fair whack in copper terms.

For this particular example though, I cannot tell you if it is worth it, as I do not have the time and inclimation to ring tranformer manufacturers and start geetting quotes. It's certainly worth an investigation, and would avoid the some of the difficulties associated with HV/MV application.