I don't want to be a miserable git ......... but, I have to say to Spacey that cabling really is not "labourer's work". There are so many considerations......
under insulation
clipped direct
run in trunking
near to heat sources
voltage drop
bunched cables etc etc .............
All of these things greatly affect a cable's current carrying capacity. Electricians have to calculate, from these, how much a cable has to be de-rated.
A standard 2.5mm cable in the right circumstances, could carry 40A. In some, pretty normal, conditions, it might be de-rated to 16A.
Then there's zoning..... diversity ........ I won't go on :o)