T

ThatMatt72

Hey all,
Excuse the ignorance here but I wonder if you lovely folk might have any opinions or better still be able to point in the right direction in the BBB.
I am being asked to move a CU from its current position, behind a fitted kitchen, under the sink and totally inaccessible, except to the countless bottles of Fairy and Pledge etc, that share a home with it.
The meter backs on to it in a recessed box. I need to move the CU all the way down the side of the house, about 8-10m and pop it back on the same wall. I was going to pop an IP65 metal enclosure in the current location and extend all the circuits (actually only 4, thank goodness (or words to that effect!!)) along the outside of the house in singles inside galvy steel trunking. The house has a concrete floor throughout so there's no popping up a board here and there and running the lot along the dirt.
So far, so simple...SO...moving on to the incoming supply side...The meter will now be about 8-10m away from the proposed site for the CU. I normally install a fused switch and then run the appropriate sized armoured (in this case it'll be 25mm) from the FS to the CU. In this instance I was toying with the idea of not doing that but to run meter tails inside the galvy alongside the extended final circuits. Is this acceptable? If not, can you point me in the direct of evidence to this end in the BBB. I have a niggling concern that the DNO only want SWA used to feed CUs or DBs when they're over 3m from the incomers, but for the life of me, I don't know where I go the info...I may even have dreamed it.
Thanks in advance for all your help with this quandry, and obviously thanks too to Pete, who will no doubt point out the fact that I should, in fact, have become a cab driver and left this electricing lark to my betters!! ;-)
 
Is this outdoor galv trunking going to be waterproof, or will all the cables be getting wet?
 
I’ve seen tails run further than 10 meters under the floor, but I would never contemplate installing it this way myself.
Nothing I remember is in the bbb, but if it’s visibly surface mounted with absolutely no chance of accidental damage maybe in exceptional circumstances this would be ok, but I wouldn’t.

Your call your design.
 
Would the tails be run through a room containing bath or shower?
 
is there room in the meter box for a 6 way RCBO CU? that would simplify things.
 
Can you not pull the cables up in the 1st-floor void and join with MF j.boxes to the new position. Or if there is not enough room in the meter box i.e. Tels suggestion install another meter box next to the existing meter box?
 
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What are these 4x cir units that require 25mm to feed them?

If its being installed in steel trunking then singles or 'tails' will be fine.
 
Have installed tails in Galv trunking before.
Followed the drawing and used 2 inch trunking, then the Forman gave me a length of SWA to strip and use the cores for the tails.
Fortunately the meter connection guy refused to connect and told the foreman to get some proper tails.
 
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Thanks all for your input. I'll try to address everyone's comments now. Sorry If I miss anyone out:

Anthony: I can't use the first floor void easily, if at all, as the room above is the master bed and fully decked out with fitted wardrobes right on top of that particular area and extending the full length of the room. The floor covering is carpet, but underneath is that dreaded green interlocking cb panels which the wardrobes are built off of.

Dave: The 4 circuits are nothing special. Just sockets, cooker, lights up and down. But the incomer has a 100 amp fuse in it, and I don't like to give the chaps at NICEIC reason to have a dig, if they inspect the job.

Spin: Thanks for that mate. So your man had no problem with the tails in galvy, but did he just want them grey sheathed like normal tails? Thats interesting that it would matter in the galvy trunking.

In conclusion I am with telectrix. I reckon popping an RCBO unit in the meter cabinet would save a whole load of headache and money. I am going to revisit that idea and see if things can be jiggled around a bit to make a little more room. If they're worried about the security of someone being able to gain access to the CU I'll install a locking one. I guess anyone could just pop the fuse anyway.

OK folks, I will have another look and let you know what I decide upon.

Thanks again to all for your 10 cents worth. It great having a few extra minds shooting ideas in the air.
 
i've moved meters on a few jobs like this. great big board and the meter stuck right in the middle. (disclaimer. it wasn't me, nobody saw me do it, and you can't prove it (fingerprints wiped and no DNA left at scene)).
 
i've moved meters on a few jobs like this. great big board and the meter stuck right in the middle. (disclaimer. it wasn't me, nobody saw me do it, and you can't prove it (fingerprints wiped and no DNA left at scene)).

But the discarded smoke-packets, empty beer cans and cheesecake crumbs gave you away in the end. :D
 
I normally install a fused switch and then run the appropriate sized armoured (in this case it'll be 25mm) from the FS to the CU. In this instance I was toying with the idea of not doing that but to run meter tails inside the galvy alongside the extended final circuits. Is this acceptable?

I think you may be well advised with not toying with the idea and staying with the more conventional solution,the other idea seems to be a whole lot of bother for what would end up as a substandard design
 
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Dave: The 4 circuits are nothing special. Just sockets, cooker, lights up and down. But the incomer has a 100 amp fuse in it, and I don't like to give the chaps at NICEIC reason to have a dig, if they inspect the job.

I'm working on a job where the incomer is fused at 1250A, based on your logic should every submain be sized for 1250A?

They won't have a dig if you design the circuit properly, and to b eperfectly honest if you're designing the circuit based on your perception of what the niceic may or may not like you need to grow a spine!
 
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i've moved meters on a few jobs like this. great big board and the meter stuck right in the middle. (disclaimer. it wasn't me, nobody saw me do it, and you can't prove it (fingerprints wiped and no DNA left at scene)).
They've got CCTV in the meters now so unfortunately you've been collared!
Hey all,
Excuse the ignorance here but I wonder if you lovely folk might have any opinions or better still be able to point in the right direction in the BBB.
I am being asked to move a CU from its current position, behind a fitted kitchen, under the sink and totally inaccessible, except to the countless bottles of Fairy and Pledge etc, that share a home with it.
The meter backs on to it in a recessed box. I need to move the CU all the way down the side of the house, about 8-10m and pop it back on the same wall. I was going to pop an IP65 metal enclosure in the current location and extend all the circuits (actually only 4, thank goodness (or words to that effect!!)) along the outside of the house in singles inside galvy steel trunking. The house has a concrete floor throughout so there's no popping up a board here and there and running the lot along the dirt.
So far, so simple...SO...moving on to the incoming supply side...The meter will now be about 8-10m away from the proposed site for the CU. I normally install a fused switch and then run the appropriate sized armoured (in this case it'll be 25mm) from the FS to the CU. In this instance I was toying with the idea of not doing that but to run meter tails inside the galvy alongside the extended final circuits. Is this acceptable? If not, can you point me in the direct of evidence to this end in the BBB. I have a niggling concern that the DNO only want SWA used to feed CUs or DBs when they're over 3m from the incomers, but for the life of me, I don't know where I go the info...I may even have dreamed it.
Thanks in advance for all your help with this quandry, and obviously thanks too to Pete, who will no doubt point out the fact that I should, in fact, have become a cab driver and left this electricing lark to my betters!! ;-)
You'll be installing a switch fuse as the new CU is >3m from the meter therefore only the tails from meter to switch fuse need to be 25mm. From the switch fuse to new CU the 'tails' need to be sized according to the size of the fuse in the switch fuse, so probably 16mm.
 
is there room in the meter box for a 6 way RCBO CU? that would simplify things.
Quick update, I went for this option. I got the CU to breathe in and managed to squeeze it into the meter cupboard as you suggested. Cheers for that telectrix!
 
Tels the Daddy..:blush::blush:
 
Quick update, I went for this option. I got the CU to breathe in and managed to squeeze it into the meter cupboard as you suggested. Cheers for that telectrix!

Pics of the new install?
 
I stopped taking photos a while back. I am there doing another job in the next few weeks, I'll grab a pic and bung it up here then.
 
The DNO will give you a maximum length for tails. (usually 3m). You described the best way earlier which is to run them into a fused iso and then run off SWA it singles if protected correctly. Neither need RCD protection so won’t be a problem.
 
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Meter Tails in Galvanised Trunking...Is that a thing?
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