Discuss Consumer unit change in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

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Peter Woodford

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Can you tell me when changing a consumer unit I know that the tails have to be changed to 25mm but if you cannot gain acess to the old ones can you just put a notice on the cert. In my case the meter is on the outside of the house and consumer unit is in the garage at high level. The meter is on the outside wall to the kitchen I am thinking the meter tails go up the wall inside the ceiling void a across the kitchen and hallway and into the garage at high level then into a henry block and I was going to
Come out of this with 25mm would this been ok
 
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L

lister

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  • #2
how far apart are the meter and the cu?
if more than a couple of meters you gonna open a can of worms with this one:D
 
A

amp

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  • #3
work out your maximum demand to see if 16mm tails are big enough

work out your max demand and see ir they'er still big enough.
had this problem before try pulling new cables inton old
 
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S

Spudnik

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  • #5
Tails only need changing to 25mm if the main fuse is rated at 100A.

Other than that, 16mm is fine.
 
I

iceman

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  • #6
hi iv just installed a new c/u with 100a main switch with 9 circuits on it total 240a when added the breakers up iv changed the earth to 16mm but left the 16mm red and blacktails in reason bein cos i gotta cut the seals to install 25mm tails could i get away with out changin tails id say there about 2 metres max between to c/u and the main fuse cut out???
 
hi iv just installed a new c/u with 100a main switch with 9 circuits on it total 240a when added the breakers up iv changed the earth to 16mm but left the 16mm red and blacktails in reason bein cos i gotta cut the seals to install 25mm tails could i get away with out changin tails id say there about 2 metres max between to c/u and the main fuse cut out???
if there is a 100 amp main fuse theyve got to be changed. cut seal and reseal after all call dno to reseal once finished ;)

Tails only need changing to 25mm if the main fuse is rated at 100A.

Other than that, 16mm is fine.
hi jason. is that still correct :confused: as it states in osg 2.2.3 minimum size of tails as 25mm2 even though 16mm2 is fine for 60/80 amp feeds :eek: so would this not be a departure from regs :confused:
 
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I

iceman

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  • #8
25mm tails fitted today wot a nitemare job they almost ripped me consumer unit off the wall fittin the ******s lol atleast now when i finaly get round to gettin assesment done he cant moan! lol
 
J

johntom

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  • #9
Hi
can anyone confirm that all CU changes must upgrade the tails to 25mm as per OSG? also previous posts mention the distance between the CU and meter but this isn't in OSG?
 
Hi
can anyone confirm that all CU changes must upgrade the tails to 25mm as per OSG? also previous posts mention the distance between the CU and meter but this isn't in OSG?
hi johntom,
according to osg minimum tail size is 25mm, but given current carrying capacity you should be able to determine from fuse size and it would be hard to prove you wrong ;)
 
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