extension

[r.b]

I have got an extension to do there is an existing house with existing board with 25mm tails fed into it.I want to break into this tails with henley blocks to a sub main obviously 25mm tails goin to the sub main.The cut out is 100 amp so what size sub mains can you get as long as its 100 amp this should be ok shouldnt it?.I want an armoured coming out of the sub main to the new house extension board as its 25mm tails I was going to put in 25mm armoured?what are your thoughts?

 

[NozSpark]

Demand, length, installation method, Ze, Zs, volt drop (and then allowing some for final circuits),,, all things you need to know or work out before tyou can determine the cable size you need.

You can't just whack in a 25mm sub main and exect it to comply, I had to do a 35mm 3 core SWA submain in a house before for an 80A demand!!

forgot to say at you'll also need to know what cable type you are going to be using

 

[SPECIAL LOCATION]

I have got an extension to do there is an existing house with existing board with 25mm tails fed into it.I want to break into this tails with henley blocks to a sub main obviously 25mm tails goin to the sub main.The cut out is 100 amp so what size sub mains can you get as long as its 100 amp this should be ok shouldnt it?.I want an armoured coming out of the sub main to the new house extension board as its 25mm tails I was going to put in 25mm armoured?what are your thoughts?

My thoughts??????

Could be ok on 16mm or 10mm or 6mm???????

Dunno?

Or may all just burst into flames cuz its already overloaded!!!!

1/ Get someone who understands electrics to design the stuff for you......

or

2/ Just do what you are going to do anyway and don

 

[ProDave]

And one vital thing, where is your sub main going? A cu right next to the existing one, or a CU in the extension?

If the latter then some form of switch fuse or isolator will be needed.

 

[Theorysparky]

Treat the extension as a new build house

demand from sockets,lights,smokes etc

distance from original board

decide whether you need a switched fuse/double pole isolator/mcb

then decide the tail size

start from the end and work back

if you have trouble with that then.........