New tncs supply, 16mm ok?

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The previous electrical supply comes up through the ground via metal conduit and is terminated into henley blocks inside metal trunking, then into the meter.
And also, presumably, from those Henley blocks up through the conduit to the meter for the upstairs property.

Which surely makes it the DNO's cable?


The UKPN cutout will be in that burnt out cupboard once it is rebuilt. I am running a cable from the cutout to the meter.
Surely that's their cable?

Why have they subcontracted the installation of it to someone who has to ask this:
I was thinking of installing a 60amp wylex isolator supplying 16mm 3 core swa. The run is about 15m long. Is there any problem with this or will the swa need to 25mm?
?
 
UKPN will not renew the cables to the two properties, only to the cutout. The cable from the isolator that i want to install to the meter will belong to the council. Is this unusual? I've had a job before in an where an isolator had to be renewed in an intake cupboard, UKPN said that did not own the isolator or the cable from it to the meter in the flat. The council was given permission to remove the main fuses to the building so that the work could be completed.
The main thing that i wanted to know is if they would insist on a 25mm cable even though I would be supplying a 60amp switchfuse.

Thanks anyway and apologies if you did not understand what I was talking about.
 
I can't believe the DNO are happy to let you use a switchfuse like that. It is open to abuse.
 
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I can't believe the DNO are happy to let you use a switchfuse like that. It is open to abuse.
Quite so - and particularly if (as sounds to be the plan) the cable eminating from it disappears into some trunking and then reappears a few meters later to be connected to the supply-side of the meter!

Kind Regards, John
 
Who owns the property and what are their plans for it?
The DNO should actually be dealing with them not you.
Once the DNO and the property owner agree what is needed then if I was you I would get it written down and agreed between all three of you exactly what is required of you. If the work involves DNO stuff then they should give you a permit to work.
It does sound as if you are 'piggy in the middle' at the moment and to be frank, talking to us is not going to resolve the matter.
 
This looks like a typical council "legacy" job that the DNO is trying to make the best of a bad job out of.

If the work involves DNO stuff then they should give you a permit to work.

The term Permit to Work in a DNO has a whole different connotation and will only be used for work on HV equipment.
 
This looks like a typical council "legacy" job that the DNO is trying to make the best of a bad job out of.
Well a good starter for ten would be to explain to the spark exactly what is required.
 
UKPN will not renew the cables to the two properties, only to the cutout. The cable from the isolator that i want to install to the meter will belong to the council. Is this unusual? I've had a job before in an where an isolator had to be renewed in an intake cupboard, UKPN said that did not own the isolator or the cable from it to the meter in the flat. The council was given permission to remove the main fuses to the building so that the work could be completed.
The main thing that i wanted to know is if they would insist on a 25mm cable even though I would be supplying a 60amp switchfuse.

Thanks anyway and apologies if you did not understand what I was talking about.

Depends on the property type/demand.

It used to be 16mm split concentric for small properties, gas heating, 25mm for anything bigger and if there were night storage heaters.
Now there is a rule of thumb that 25mm is used, though occasionally engineers request 16mm, normally if it makes their life easier.

In the situation you describe, I would put 100A fuse in 1st cut out, run 35mm Al LS0H Orange split concentric cable (to comply with G81). We would install a second Henley cutout next to meter with 80A or 60A fuse. Both cut outs would be sealed.
 
In the situation you describe, I would put 100A fuse in 1st cut out, run 35mm Al LS0H Orange split concentric cable (to comply with G81). We would install a second Henley cutout next to meter with 80A or 60A fuse. Both cut outs would be sealed.
Why not just one cutout (the first one) with the 80A or 60A fuse - is what you say just so that there is a fuse (usable for isolation) close to the meter (and probably CU)? In terms of faults, I wouldn't think you'd get much discrimination between 80A and 100A fuses, would you?

Kind Regards, John
 
You're probably right about the discrimination but thats the practice we use.

A second cutout is probably used as you say for isolation for mainly metering. We never use Henley blocks supply side, even though they can be sealed.

SSE use a red Henley 7 carrier which is just a straight link, I'd imagine in this scenario they'd put one of these in the first cut out and the riser would be protected by 200A network fuses.
 
I've dealt with a couple of these, it sounds to me like the two properties had a looped supply, as the service cupboards appear to be back to back, one is looped out of the top side of the other one's cutout, and it enters through a metal conduit, with both meters in the service cupboards.

Quite what UKPN have actually asked for, I don't know, but I would go for a separate cutout in each service cupboard, with the meter adjacent, and a fused isolator. The customers electrician would then do what he wants to out of the fused isolator and everyone is happy. I have a suspicion this is what they actually want, but it hasn't been communicated properly. If there's a convenient outside cupboard then the meter would be much better housed there than inside the house.

Edit- another point that may be confusing things is that it isn't UKPN's responsibility to sort out the meter, it is the suppliers, and the customer will need to talk to the supplier about it as some suppliers won't talk to DNO staff at all (unless they find something wrong thats the DNOs responsibility....)
 
I still find it odd that a DNO would request a device to make theft nice and easy.
 

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