Meter Tails...!! 16mm / 25mm

[DurhamSparky]

Hi,

Going to be doing my Elecsa Assessment soon and house i have chosen to do the work on is a TNCS supply 6 way board with excellent access!!

currently it has 16mm tails from meter (located about 2M away on ouitside wall) earth is in 16mm and bonding is 10mm so not to bad!

however looking at previous posts and stuff in onsite guide it says the tails must be 25mm ( section 2.2.3)

now im confused??? is that for new builds or can i get away with utilising the existing 16mm cables??? or should i install new 25mm tails !!


much appreciated!!


steve

 

[DurhamSparky]

didnt want to really faf about with cabling!! im doing this job cost price!! argh!! oh well best order few meters of 25mm brown and blue tails!!! (go for 25mm then i don't care what size fuse it is..)

may investigate to see if current tails are in metalic conduit!!

 

[pennywise]

Hypothetically could you put earthed metallic capping over the area where the tails are running below the surface as long as the tails are going directly upward (chances are thats never going to be the case and you'd probably nail the cable in the process) , I would never do this as it's not best practice and would look ruff as anything, but does it matter that the capping isn't buried with the cables.

 

[DurhamSparky]

probably not!! cable comes in sideways and along wall then i guess goes up to the box..!!

oh well going to investigate bit more!!

cheers chaps...!!

 

[pennywise]

Sorry m8 didn't really mean in your situation It was just a discussion point as to whether it would comply. Good luck on your assessment when it comes.

 

[sparks1234]

oh yeah no snipping required the seal was already broken and fuse fell out into my hand!

yea...they all do that

 

[MarcT]

This is an extract from an ECA circular, hope it helps:

Periodic Inspections for Older Installations
(a) For 63 Amp and 80 Amp cut-out fuses, 16 mm2 meter tails are correctly sized for both free air
or clipped direct to a surface installation methods and no comments are required. See note (i).
(b) For 100 Amp cut-out fuses and 16 mm2 meter tails installed in free air, the following wording
should be entered onto the PIR "It is recommended that the meter tails in this installation be
replaced with 25 mm2 size if and when the service head or service meter is replaced".
See notes (i) and (ii).
(c) For 100 Amp cut-out fuses and 16 mm2 meter tails installed clipped directly to a surface,
Code 2 and the following wording should be entered onto the PIR "The meter tails in this
installation require either re-installing in free air or replacing with 25 mm2 size tails". See note (ii).
Notes:
(i) For meter tails installed in walls, trunking or similar, further de-rating is required and the
following sizes should be present:
Cut-out size
Installation
method
Minimum size
63 Amp In trunking or conduit
(ref method B)
16 mm2
63 Amp In trunking or conduit buried in an insulating wall
(ref method A)
25 mm2
80 Amp In trunking or conduit
(ref method B)
25 mm2
80 Amp In trunking or conduit buried in an insulating wall
(ref method A)
35 mm2
100 Amp In trunking or conduit
(ref method B)
25 mm2
100 Amp In trunking or conduit buried in an insulating wall
(ref method A)
50 mm2
(ii) The free air rating of 16 mm2 cable is greater than 100 Amps but DNOs specified a size of
25 mm2 for cut-outs of 100 Amp rating.
(iii) Where the size of the cut-out fuse cannot be ascertained, then the inspector has the option
of either assuming 100 Amp size, or contacting the DNO.
(iv) The thermal withstand under short circuit conditions of is not a limiting factor on the size of
cables required.

 

[DurhamSparky]

rang NEDL (distributor) and the person i spoke to was as helpful as a chocolate fire guard..!! she asked me why i wanted to know the size and also told me to ring the billing company i.e NPOWER then told me they wont allow the fuse to be removed unless your a

"16th edition" & "NIC EIC Electrician"



told her i was 17th and Elecsa and she kinda went quiet and went is that as same as 16th and NIC....!!

i did not stay on line much longer!!! flaming idiots!!

 

[kung]

oh yeah no snipping required the seal was already broken and fuse fell out into my hand!

Had a nasty fall once ! some kid left a roller skate next to the CU it was dark and i didnt see it and stepped on it ! woosh i flew forward and put my hand out to stop myself hitting the ground and grabbed the cutout fuse which flew out (had no seals) it made a mess on way down and pulled the tails out as well that snapped in half so put new 25mm tails in and reseated cutout fuse then sealed the fuse in to stop it happening again. It makes me mad when the DNO dont secure their fuses !
P.S. Good luck with your assessment !

 

[pennywise]

Love how the DNO always say never cut seals etc, then when you get one of their guys out to PME a TT supply they give it one look do a loop test and then say "you can do it yourself if you like"and bugger off!, got to love them

 

[DurhamSparky]

sorry another stupid question

going back to the property today to look at fuse and cable + routing (which i think is in the cavity wall so its 50mm from surface which will be nice )

to measure cable size am i right in saying i can take a ruler measure the cable edge of sheath to edge of sheath or is it core to core and x 3.14 = cable size??? (deduct bad measurements and round up or down to size cable i.e if my bad maths come out at 23.9 = 25mm2 cable or 17.8 = 16mm2



steve

 

[pennywise]

Get an offcut of 16mm green and yellow and compare it that way or a bit of 25mm and see if it's smaller. The copper core size that is not the PVC sheath.

 

[DurhamSparky]

in my hand i have what is 25mm cable and just gone to my meter on house and the cable for meter is substantially smaller..!! my house was built 2006 and my guess is that the cable is 16mm L and N




further to my ramblings...!! all confirmed...! dug up my install certificate and tails/earth = 16mm ..... should be a nice and easy check at my assessment house!!

 

[pennywise]

And you probably have a 60A or 80A company fuse.

 

[DurhamSparky]

how good are you!! 60amp!! although NEDL reckon its 100amp with there label!!

you been very helpful you really have!!

speak soon of to help some body put the fuse back in as it jumped out and scared the cat! going to tell it off and read its birth certificate!!! naughty little tinker!!

 

[pennywise]

They just put that sticker on because 100amp is the max capacity of the fuse carrier and the head.