Fuse box CCU Seals

I have a general query you may be able to answer.
In the various houses I have lived in I have often been tempted to put in a larger or more modern CCU. E.g. one with MCBs rather than fuses.
What has stopped me is the apparent inability to disconnect the CCU tails from the preceding unit (meter, distribution block etc) as these are often sealed by wires crimped with lead seals.
I have assumed you are not allowed to break these seals. Is this correct?
My confusion is compounded as I understood that the tails to the CCU are the consumers responsibility, but here you cannot touch them as one end is sealed. If you cant break these seals, how can you safely isolate the CCU to fit a new one?
Many thanks in advance
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to the meter is sealed - for obvious reasons. If you need a new connection to the meter then you need to contact the supply company. However, unless the tails need replacing for some reason there is no need to touch anything at the meter.

You pull the main suppliers fuse (the big black one before the meter) to isolate the supply, then you can connect up the new CU to the old tails. This fuse is normally sealed as well with a tag, and technically the same rules apply about this. In practice the supply co.'s don't seem to care about it if you pull this fuse.
Plenty of people - me included have done this. some have phoned up the co. and told them, others have just left it. The meter reader may reseal it when they next visit - though since they tends to be employed now just to read meters I guess many of them don't care.
I would suggest the first thing to do is fit an isolating switch between the meter and the existing CU then you can switch off the supply in the future to isolate it easily.
--
Chris French, Leeds

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snipped-for-privacy@btinternet.com says...

When I've done this in the past, I've phoned up the company, who have told me that it's fine to break the seal on the incoming fuse to do this, just ring them afterwards to let them know it needs resealing.
A 24/7 engineer told me the other day that you can break the seal on the meter as well, if you need to change / lengthen the tails, but I think I'd be a bit more wary of doing that!
I agree with the other poster about fitting an isolator switch straight after the meter - saves a lot of aggro later on!
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When I replaced mine the other day, I turned off the juice by breaking the fuse seal and withdrawing the service fuse. The bottom of the meter had a removable panel held on by a screw which gave access to the meter output terminals. This panel was not sealed, although the other parts of the meter were. I haven't bothered informing the electricity company.
Christian.
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On Tue, 26 Aug 2003 11:57:13 +0100, "Christian McArdle"

and a seal on the screw to remove the cover over the tails.
--
John

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Mine had no seal over the tails, although it looked like it might be possible to install one. If I had had the seal, I'd have been very tempted to break it. I probably would have phoned the electricity company then.
Christian.
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