What cable should I use to make a custom 4 way extension lead to run from house to shed? Would this be ok? http://www.screwfix.com/p/3-core-reel-flexible-cable-white-1-5mm-x-15m/47395 All the extensions we have seem to be 1.25mm so presumably 1.5mm is also ok? Would run along house and then underground in some tubing to power a lamp, a printer and a fan heater during the winter. Many thanks in advance.