Cable Selection

Check out the current edition of the Wiring Regulations issued by the Institution of Electrical Engineers. Though applicable to the UK its contents can be applied to many other parts of the World.

Good answer, read the regs of you country! The rule of thumb is:-

Use your thumb to turn the pages!

It is so simple by the time you waste energy on surfing internet contact your nearest cable dealer .All cable manufacturers are providing you this information free of cost.

Here in New Zealand we have a free program from General Cables called Gencalc which is very useful for NZ conditions. The restrictions are well documented in the help section and should be read carefully.

http://www.generalcable.co.nz/new_zealand/download_genCALC.htm

The only rule of thumb you should ever use is not to get it between the nail and the hammer. I keep mine in my mouth where it can't cause trouble!

Yep, ask the local cable bloke or sparkie.

Cables get current ratings to allow for the fact that the heat dissipated by the conductor will heat up the surrounding insulation and eventually degrade it. So, the size of cable needed is dependant upon the actual heat generated (i^2RT), the way it's laid (in fresh air or bundled with lots of others inside an insulating cover) and the type of cable/insulation (ie PVC insulation or mineral insulated). Jeff

The following link takes you to a table of American Wire Gage specs:

http://www.powerstream.com/Wire_Size.htm