Meter tail length

[bradf0rd]

I may need to replace my current consumer unit as it has no RCD's on board.

The current CU is in a cupboard in the kitchen, high up, and working on it would be a real nightmare, it's really tight for elbow room.

I was wondering how far someone could move the new CU from the Electric meter - I guess the tails would now be around 1m long. The Electric meter has been fitted into a hole and cabinet in the outside wall - so I don't want to start making a new hole and stoning up the old one - is there anything that would stop anyone running longer tails and putting the new CU somewhere more friendly.

I know it is not something you go into every day, but there are a few places it might be easier to access it - yes I have also thought about the need to re run the mains and light circuits if I do this too.

I noticed on Ebay, someone is selling 5 and 10m lengths of tails but are these bulk amounts that are made to be cut up for 5 or 10 jobs to comply with 17th Edition ??

then eventually when I come to install the kitchen, the walls would be free and I wouldn't need to start organise the kitchen cupboards around the CU ..

 

[RF Lighting]

I'm sure your electrician will be able to supply his own meter tails. You haven't even mentioned what size the ones on eBay are, and wether they are BASEC approved.

Yes a CU can be moved, but this is again notifiable work.

 

[sparkiedave]

Meter tails can be up to 2 metres long over that length they have to be fused, they can't be burried in plaster less than 50mm from the surface they would have to be protected by a 30mA RCD, which would then cause problems with discrimination, but your best bet would be to get a sparky to sort it out for you

 

[Taylortwocities]

I agree re the sparky remark. Permitted length of meter tails is a matter for the DNO.

If the tails are long then you could run it in SWA or split concentric - you cant just bung an RCD on the incomer - that would make it a single point of failure and would cut the supply to the whole house if an earth fault occurred.

 

[Spark123]

Not sure split con doesn't require supp protection

 

[Taylortwocities]

UMM, you probably right, only earthed on one half.. curses SWA it is then...........

 

[rebuke]

One thing to point out, as it's not necessarily obvious, is if you run the tails in earthed metal conduit anywhere to avoid needing RCD, then the phase and neutral tails must be in the same piece of conduit, otherwise you're in breach of regulation 521-02-01, otherwise you can induce eddy currents in the conduit (see http://www.roltesting.com/UserFiles/File/eddy.pdf for more info).

Personally though, I'd just use appropriate SWA...

(If anybody's wondering, this was pointed out to me by a friend as my original plan for nicely glanding the tails into my CU needed some modification since I have a steel CU (a small slot cut between the two gland holes so neither tail was completely enclosed))

 

[properleckie]

Get your registered leckie to change consumer unit to switch fuse, then run SWA to new prefered position.
In this region REC say 3 meters between meter & first point of isolation, reason given is for emergency services if called to know where to isolate system without removing cut out fuse, the actual tails length not counted.
I use wylex 110M or similar.

 

[Chri5]

I've always worked to 3m max tails.

I thought it was acceptable to have a 100a isolation switch as a demarkation point if you needed to extend beyond 3m ?

 

[properleckie]

chri5, you are correct, but I find switch fuse has more room to terminate SWA! isolators tend to be a bit tight.

 

[Chri5]

MK 100a switches and min housing's are orrid when terminating simple 25mm tails, armour would be an absolute mare