sub mains 16ml

[Scott F]

evening all >osg states incoming tails to a house to be 25ml with 16 ml earth now i have come across a fair few properties with tails going to 63 amp main fuse sw then down to 16 ml where in the regs does it go over this ive looked under submains and distributors supply but to no avail>i have this situation where from fuse sw 16ml swa runs 100 metres to cu in house

 

[uksel]

i'd go with the OSG - ensure the main breaker/RCD at the CU is rated at no more than 63A

16mm also covers you for 83 Amps when clipped Direct, so provided you stay less than this I don't think you'd have many problems

does the phrase 'reasonably practicable' come to mind. this is where you being the competent person should make an educated decision to err on the side of safety. safety notices regarding the size of the main breaker would seem appropriate

also make a code 4 in observations perhaps?

any other thoughts...?

 

[beaver74]

bs7671 does.nt cover supply authority side only consumer side of installation that is why you cant find anything

any one care to conferm

 

[Scott F]

bs7671 does.nt cover supply authority side only consumer side of installation that is why you cant find anything

any one care to conferm

are you saying that it is the supply authority installing the metal clad switch fuses .then putting in 16ml >i only ask as id always assumed it was an elecrtrical contracting sort of job