Yes there is a formula for calculating the current rating of cables depending what country you are referiing to.
In the UK, cable has to be manufactured to the limits dictated by the relavent British Standard.
The guidelines for cable ratings are set out in the IEE wiring Regs BS 7671 but these have to be ammended by correction factors for the particular application.
There area many different ratings for 1mm sq copper depending upon the cable type -all too numerous and time consuming to list here.
In the UK, the latest edition of the Wiring Regulations published by the Institution of Electrical Engineers is a valuable tool, and contains all the information needed to match current-carrying requirements, protection level and conductor sizing across all types of installations, domestic and industrial, and all types of cable.
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current carring capacity
Re: current carrying capacity
