Changing Mcb

[ezekiel]

I mentioned in a previous post that a 40a mcb ran to a 13a fcu providing power to my loft - i have also just noticed a 32a mcb running to garage (not connected) would it be advisable to swap the mcb's over so the loft runs from 32a (to a fcu powering 2 double sockets + fcu with 3a for lights)
and use the 40a to garage installing a 2 way unit with rcd

 

[ColJack]

without knowing the cable sizes it's not a good idea to go changing fuses about..
also, doing so is notifiable to the LABC under part P of the building regs, as you are altering the circuits protective measures..

 

[ezekiel]

cable running to loft is 2.5 (on the 40a mcb) cable running outside is swa but not sure what size -

dont think the loft should be on a 40a mcb
dont think garage should be run from fcu in kitchen

planing on discon the cable to garage and thought the 32a would better serve the loft than the 40a

 

[dingbat]

cable running to loft is 2.5 (on the 40a mcb)

Eeek!

DIY lash-up alert!

Actually, the current demand on that cable will be limited by the 13A fuse in the FCU, which is allowed... but not many people know that and in any case, no spark would ever do that when it is so easy to use a lower-sized circuit breaker (16 or 20A would be most appropriate here).

My advice would be to get somebody in to look at your whole installation - this sort of horror is rarely found in isolation.