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

DurhamSparky · Jan 17, 2010

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 · Jan 18, 2010

excellent, on closer inspection of the metering set up and supply tails i can confirm they are 16mm on a 80amp fuse with the cables clipped to the wall and enclosed in trunking (apart from where it disapears for about 50cm under plaster board and enters the back of the consumer unit..!!! shall i change tails to 25mm or leave 16mm!!

solo2771 · Jan 19, 2010

80 Amp In trunking or conduit
(ref method B)
25 mm2

DurhamSparky · Jan 19, 2010

thats what i bought!!! 7m of 25mm L&N colour tails plus 16mm earth...!!

David. · Jan 19, 2010

best check about the length of tails and the need of a switchfuse is over a certain length. 3m i think then you need one.

D.

andekoch · Jan 20, 2010

correct over 3m you need a switch fuse at the start of the run.

Robo · Jan 23, 2010

iv recently bought a house.Fitted new db.However its about 7 metre run for the tails. it has a switch fuse at the 3m point inside a cupboard and then carried on the further 4 metres.Is this ok or have i been mis informed.

AEC · Jan 25, 2010

Lenny said:
If it is a 100A fuse then the tails need to be 25mm, also if they are buried in the wall, not enclosed in metallic conduit, they will need RCD protection.

Can you run surface trunking to the DB??

Think your having a laugh about the RCD. Or are you serious?

Guest123 · Jan 25, 2010

Deadly......unprotected (i.e no armour or earthed metallic conduit), PVC PVC cables buried in the fabric of the building at less than 50mm....additional protection by RCD required.

This is why the IET ammendment to the 17th ed and the ridiculous "RCD everything" is on the way.

MarcT · Jan 25, 2010

Lenny said:
Deadly......unprotected (i.e no armour or earthed metallic conduit), PVC PVC cables buried in the fabric of the building at less than 50mm....additional protection by RCD required.

This is why the IET ammendment to the 17th ed and the ridiculous "RCD everything" is on the way.

I presume electricians houses to be exempt