Determination of Size of Conductor/Cable

The size of the conductor or cable may be determined by the current (amperage) and the voltage requirements. If you can find that information, you can check the National Electrical code table 301.16 and match the ampacity of the conductor to your requirements. Also, take in consideration the if the conductor will be copper or aluminum. Aluminum conductors will require a larger size in order to carry the same current.

If you need to determine the size in order to install the cable or conductor inside a raceway, the NEC also have tables that will provide that information.

The only formula I can think you can use in order to determine the size will requirer you to know the distance, ampacity and resistance per foot of the conductor you may want to select and see if it can carry the load to be connected. In this case you will need to have a manufacturer's table that will provide you wit this info.

Hope this helps.

Thanks! -- Saved me a lot of typing!

Instead, try (a+b)(a-b) = a²-b².

Or (a+b)(a+b) = a²+2ab+b².

Or (a-b)(a-b) = a²-2ab+b².

Your formula mixes up everything,

→ British Standard 7671.

Your question is not clear.If you have a wire and if you want to know its size(cross section) you should measure the diameter,type(solid/flexible/stranded),material(copper/aluminium and properties)size of strands(if multi stranded) and refer tables provided by any reputed manufacturer.Calculating may not give accurate results.