Cable from isolator to consumer unit

[Taylortwocities]

Need some guidance as havent come across this before.

Hi guys and gals

I have a consumer unit to change. The existing board is approx 10metres from the incoming supply (TN-S). 16mm tails from the meter go to an isolator switch with a 60A (BS3036) fuse.

The cable from the isolator to the ccu (I believe) is 10mm T&E with a separate 6mm main earth conductor.

I will be upgrading main earth & bonding conductors to 16mm & 10mm but would it be necessary to upgrade the cable from the isolator to the ccu given that the cable calcs say that 10mm is OK at 60A over that distance?

Your input very much appreciated!

TTC

 

[Spark123]

Where is the MET connected? Should 10mm² be protected by 60A BS3036?

 

[Taylortwocities]

currently 10mm from incoming to MET next to meter then 6mm from there to existing fuseboard. All this will be upgraded.

I think the BS3036 scroggs the calcs. 0.725 gives me only 46A for 10mm.

Wonder why they installed it like that. I'm gonna have a closer look & hope its 16mm T&E and not 10mm.

TTC

 

[Spark123]

What size is the incoming supply? The meter tails are 16mm² which gives a main earthing conductor of 16mm² (table 54G unless you want to go into adiabatics), 10mm² MEBs. Afaik the CU can be treated as a submain hence the CPC in the cable to it needs sized in the same way, the cable needs checked for the fuse size anyway.

 

[Taylortwocities]

Yes thanks. I'll be back later next week when I'm back on site.

Have a good weekend.

TTC