Meter tails issue

[adsmith]

Hi guys

I'm installing a CU in a new build and have a couple of questions I need some guidance with regards to the meter tails.
I need to drill a hole through the wall (for the meter tails) to access the main supplies which are located in the recessed box on the outside of the property. I am going to use 25mm tails. My question is the tails will be ran in a stud wall to the CU but my concern is they are not protected from nails screws in wall etc. Do you guys used armoured cable? Cant imagine many people carrying round 3 core 25mm cable? Also are meter tails ented the CU via rear entry or do they have to be secured to CU via cable gland?

Thanks for the help

 

[MJPD29]

How long is the run? Personally I'd probably use swa if it's inside the stud

 

[telectrix]

if tails are < 50mm deep in the studded wall, then they need RCD protection. this is not good as a fault anywhere on the installation could take out the lot. SWA or steel enclosure is advised. if tails are > 3m length then a switch fuse (In < that of supply fuse) at source is needed, so if fused down to 80A or 63A, 16mm SWA would be the way I'd go,

 

[Andy78]

You would need to follow cable impact regulations as normal as per 522.6.
You may also need to protect the circuit with a fuse if it is long enough.
16mm cable, either tails or SWA would be more manageable.

 

[buzzlightyear]

How far is the meter tails for the main cut out ?

 

[telectrix]

just done a job --- 10m tails from relocated intake to outside meter box. 80A supply fuse to my 63A KMF via meter), 16mm tails (in free air) to CU.half a day, and acquired 8m concentric for the scrap box.

 

[adsmith]

The run is approx 3 to 4m. I'm not entirely sure of the main fuse size yet as I have not been down to the property since the supplies have been installed. I presume it will be 100amp. So are you guys suggesting from the main supplies from the street which will be already fused (presumably 100amp) I can go to the meter then from the meter to a reduced rating kmf then from there 16mm swa to my consumer unit?

 

[ferg]

Is this your own job or are you looking for information on how someone else is likely to carry out the work?

 

[Ian1981]

The run is approx 3 to 4m. I'm not entirely sure of the main fuse size yet as I have not been down to the property since the supplies have been installed. I presume it will be 100amp. So are you guys suggesting from the main supplies from the street which will be already fused (presumably 100amp) I can go to the meter then from the meter to a reduced rating kmf then from there 16mm swa to my consumer unit?

You may find that you do not require a switch fused isolator if your tails are only 3 meters.
I’d make an enquiry to the local DNO