"dave L" wrote in message
m...
HI,

I decommissioned my electric shower so there is nothing attached to
that 30A circuit. I want to add a load of lights to the master
bedroom/ensuite which will (at full load) overload the exsting 5A
lighting circuit. I can't add a new circuit to the consumer unit,
plus the cables exiting the consumer unit are chased in to the plaster
which I don't want to rip out.

Is there a good reason not to connect my new lights to the
currently-unused 30A cable? Should I change the 30A fusewire for 5A
if I do connect them? IE, have 5A fusewire connecting to some 30A
cable which connects to 5A cable which supplies approx 1kw max load of
lighting.

Also if in the future I upgrade my fusewire consumer unit to one with
MCBs will any decent sparky (i'm wouldn't install the new CU ) refuse
to connect 30A cable to a 6A tripswitch?

Thanks a lot.
As long as you de-rate the protection (ie. change the fuse to 5A) then
you're ok. You could run the whole lighting circuit in 6mm cable if it
floats your boat - and I'd happily connect it to a 6A breaker (and YES I'd
consider myself a decent sparky - my plumbing on the other hand...)
Regards, Richard