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Help with details of relocation of consumer unit and tails

Postby comasic » Thu Jul 10, 2008 11:30 pm

Hi, after reading through many of the good posts here, i still need a little more help, as i could not find a post that covered my question.

I need to know a little more about what to expect when requesting a supply meter to be moved.

The situation is that after a building extension is completed, the old meter and consumer unit will have to be relocated.
The meter is going to be relocated on an external wall in a standard meter box (for easy access and reading).
This will be done by the electric company etc...
The consumer unit is going to be reloacted and replaced with a new one.

The Information i need to clarify is; what is the maximum distance allowed between the new sealed supply fuse and the new consumer unit and what type of wire can be used to make the connection.

Im not sure if the electric company will provide the tails.
I know a lot of fuss is made about meter tails and I need some pointers.

I think the distance from the sealed supply fuse and the new consumer unit will be around 10 meters.
The consumer unit will be 100A rated Isolator etc...

Thanks in advance for your feedback.
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Postby stevenc1603 » Fri Jul 11, 2008 10:52 am

I don't know what the reg's say, or indeed if they have been updated but in my house the meter on the outside of the house is a good 10 meters away from the consumer unit. As far as I can see it is connected with a heavy guage 3 core cable from the meter to 3 connection blocks (one for each core) and from there what I would call double insulated tails are connected to the consumer unit.
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Postby ericmark » Fri Jul 11, 2008 11:25 am

A pain in the neck. My son has done work involving meter moves and although he could run cables ready until moved he could not connect up and they never seem to come when expected and it would often result with two jobs being needed on the same day and I would get roped in to help.
As to distance with flats using SWA it can be 30 odd meters form meter to consumer unit but with tails 3 meters is considered as normal max. Where some special situations apply the length may be longer but consideration has to be made on how are where the cables are run and with 50mm rule for non-armoured cable buried in the wall it may require armoured cable. You will normally supply tails.
Also the local authority building inspector may have some preferences and building work going on you can’t really hide the work so would have to either be through LABC or done by a Part P registered firm who have the backing of their overseeing company who would advise them in odd situations one how to proceed. So if your DIY then why not ask the LABC they are after all responsible for the site safety that’s why you have to pay them so much.
If the supply authority don’t like what they see they can and will refuse to connect which is why when my son was a sole trader I was often roped in to attend when the supply agents were due.
Never needed to do anything but they insisted that there was an electrician on site before they would connect. Some times they would ask to see all the inspection and test certificates before connection.
All best Eric

Postby comasic » Fri Jul 11, 2008 7:29 pm

Humm... I expected the long wait for the connection, thanks for the heads up on that.
Its never one company who attends, one to play with the meter and one for the tails.

It looks like i will be installing SWA and providing access to the cable run for inspection
and ensure that the SWA Rating suits the Supply + some... Just to be sure.
Ill use a small metal box at the meter end to fix the swa gland into and terminate the
ends in the electrical block (Supply fuse) provided by the electric company etc...
and treat the SWA as my tails.

At the consumer end Ill have to look at either a metal consumer unit or risk
a plastic one and try to avoid any stress on the case as it enters into the unit.
I never liked the idea of Heavy SWA cable glands and plastic cases they tend to twist a bit over time.

Like you stated above, i have been used to the standard 3 meter distances
involved in most installations and nice neat short double insulated tails.

Thank you for your assistance.
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Postby sparx » Sat Jul 12, 2008 9:07 pm

In straight answer to your original question there must be no more than 4 Meters of double insulated 'Tails' between DNO's meter & consumers main isolator. The reason given is not electrical but is so that in an emergency the firefighters etc. can easily find the isolation point for the building as it will be close to the intake box.
The usual way is to fit a 100A D.Pole switch in an enclosure back-to-back with meter box or if not possible then in an additional 'meter box' next to the DNO's one with tails between in a 'conduit' of 40mm waste pipe or similar. From isolator you can run to new consumer unit in whatever cable seems suitable eg SWA, or if instead of an isolator a switch fuse or D.Pole MCB rated at 80/63A would allow the use of 16mm2 Twin & additional CPC if run in trunking /tube up outside wall & 'clipped direct' to consumer unit.
If doing so then as flat twin/E has CPC of no more than 10mm2 an additional 10mm2 earth run with it would seem to comply as long as run not too long with regards to volt drop. regards SPARX
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