Re: Moving an electricity meter

[Man at B&Q]

On Feb 18, 10:52=A0am, The Natural Philosopher

And isolate the half the street? Yeah, right, NOT!

This is another "hardware" issue you clearly know nothing about.

MBQ

[The Natural Philosopher]

You don't appear to understand how these things work.

Every line to every house has a fuse in it, to protect the transformer at the substation from a short in the underground line. Typically these are 100A, or 200A fuses.

They are duplicated by the main incoming fuse inside the property, which is there to protect the cable from shorts that are inside the house.

I think when you don't know what you are talking about, you should keep your mouth shut.

[ARWadsworth]

It has always been the moving of the cutout that I have witnessed.

They never "cut" the cable. They open it up and splice in the new cable.

Well I have been on site for many cutout moves as I am needed to reconnect the customers CU when they are finished and they have always worked on live cables, both underground and above ground.

[Tim Downie]

Um, wouldn't that imply a radial network to every house from your local substation? Seems a hugely wasteful way to supply houses.

Tim

[Chris J Dixon]

Do you have any evidence for that?

Chris

[nimbusjunk]

Hide quoted text -

This is simply not true and EDF engineers do it every day

I have just had the head and meter moved extended by 3 meters ( November 2010) from an intergal garage to a utility room by EDF and they did exactly what you are saying they do not do

EDF dug up my drive and exposed the lead cable. The engineer then split the lead sheath with a plastic chisel as easily as you would peel a banana he then peeled off the paper and placed a crimp on the positive

He then cut off the rest of the old cable into the house.

He then joined on 4 meters of armoured cable while his mate connecte the other end to the relocated board

He then put a plastic torpedo around the sheath and filled it with epoxy and left my builder to backfill

All of this was done live and he told me several chaps were killed each year, but he did this 4 times a day

( must be horible to do this when drives have been dug up by diggers and damaged the cables)

Total cost was about =A31000

I am told by EDF that any Lloyds register contractor can do this but only EDF have a universal service obligation

HTH Phil

[Andy Wade]

ROTFL - absolute nonsense. Were you joking? It may apply in your case where you're fed from a dedicated transformer, but for the rest of us house service cables are just tapped off the street mains via underground resin-filled joints, or overhead line taps. The mains are divided into isolatable sections with link boxes (usually in the pavement), allowing them to minimise the extent of any outages following cable faults. In urban areas the mains are usually fed from both ends, with the transformer secondaries being interconnected in a mesh - again allowing faults to confined so as to minimise the number of consumers affected.

House service cables are protected against overload by the main fuse in the house cut-out (aka the supply head), and against cable faults by the upstream fusing, which is typically 315 or 500 A and is more likely to be in a link box or pillar than at a sub-station. Small size service cables for street lights etc. (usually 4 mm^2) act as their own fuses and blow-up harmlessly underground in the event of a short.

Live working on the LV mains is absolutely routine. Always 2- (or more) man teams. For a house service alteration they will normally work live. An exception is where old (pre-WW2) cut-outs and cables are involved. These can be dangerous if disturbed and they may elect to isolate the supply. The method of isolation will usually be to dig a hole and cut the service cable. Isolating half a street (even if only one phase) is simply not acceptable, unless there's no alternative.

That's my understanding anyway. Hopefully 'The Wanderer' will chip in if I've got anything wrong.

[Clive George]

Suspect he was over-egging on the people getting killed thing - even one death would get the HSE getting medieval on them, but the rest was interesting, ta.

[Sam Holloway]

Probably via ouija board.

Sam

[Andy Wade]

Agreed. Also note that the DNO side of EDF is now known as UK Power Networks, have been sold to Cheung Kong Group last October[1,2]. (So we now get Far-Eastern electricity instead of French...)

The new 'armoured' service cable referred to was almost certainly a concentric type: line conductor in the middle with the combined neutral & earth formed by surrounding strands, and no 'armouring' /per-se/.

[1] Useful info here:

[Tim Streater]

We've got two wires (horizontal separation about two to three feet) coming across the field opposite, which drop down to a transformer on the last but one pole. From that to pole outside my house, two wires (vertical separation about 6", near as I can tell).

Single fat wire comes from that pole to my house, and twisted fat wires go on down the road to about four other properties.

Is that fuse you're referring to, then, at the point where the fat wire leave "my" pole to come to my house?

[The Natural Philosopher]

inside my substation, there is exactly that. I know because it blew when a digger sliced through the house feed.

Then they replaced it, it blew again after a day.

Then they put in 200A "so that when it goes, it will take the cable fault with it and we can identify where the problem is'

It did, they did, we got a digger in and lifted the cable. Sure enough the idiot who dug the new foundations had smashed it and not told us. new bit spliced in, fuse in substation replaced, backfilled the hole, and its been fine ever since.

[The Natural Philosopher]

Hide quoted text -

what lead sheath? Mine is armored coax with steel cables wound round it?

No chance of tackling that with anything less than cutters or an angle grinder or a digger bucket)

No paper in my cable.

That's the only bit that tallies with my experience.

All I can say is that none of this tallies with my installation at all.

The susbtation is designed for up to half a dozen separate circuits. Sort of corner of the street box. There is a potential place for a fuse in every one.. I happen to be the only one on it, but that's the way the new kit is.

I emphasise this is a very small susbstation, the size of a deep freeze, that takes 11KV and turns it into about 500A worth of 240V.

Installed about 1998 IIRC, when I went from overhead pole mounted transformer for the house, to undergrounded installation.

It sounds really dangerous to me, and only possible with lead sheathed older cables, which may be wired up differently.

My substation appears to be the sort of thing you put in a new housing estate, to feed half a dozen houses.

[The Natural Philosopher]

well if that is so, I have never seen it. I assumed standard practice was followed in all installations. If its otherwise, I stand corrected.

[The Natural Philosopher]

Apparently I was wrong, and old installations are not fused the way mine is.

[Manticore]

Only last week, a neighbour having an extension built had to call out the leccy board (don't laugh, I'm old :-) ) when the JCB driver pulled and snapped the feed cable into her house. Cable jointers repaired it live.

[Andy Wade]

It's not so much age as urban v. isolated-rural. The only situation (AIUI) in which there will be a dedicated upstream fuse for 'you' is where the transformer serves your property and no others. Tim's situation is quite common, with a common fuse on the same pole as the transformer and the supply then branching to feed a few premises.

[djc]

Can't be right. My meter is in the hallway on the ground floor. The consumer unit in a cupboard in my 2nd floor flat.

>

[The Natural Philosopher]

When was that built?

I am pretty sure I had to rather compromise where my CU went, to comply..in 2000.

[ARWadsworth]

That is very common. The maximum distance for meter tails is usually 2 to 3 meters. However the way round this is to install a fused isolator close to the meter with a fuse that is smaller than the cutout fuse and supply the CU from the isolator.