how to find ampere rating in high voltage system

Oop! With the mechanisation of our day-to-day life, how lethargic have we become! We have habituated to seeking short-cuts, thumb-rules & formulaes, rather than undertaking precise calculations and referring to Standards & Manufacturers' Catalogues.

The ampere capacity of any cable, under standard conditions of installtion & operation, is given in any cable manufacturer's catalogue. Pl. refer to them and apply appropriate raeting factors.

Basically, in HV, right cable sizing is not only done on the basis of ampacity but there are another parameter also i.e. Short circuit suitability which decides minimum conductor size required for system fault level that cable can withstand. Then current carrying capacity for which we have to refer manufacturers catalogue which specifies how much deration we have to consider as per various factors like ambient temp, type of laying the cable, etc as applicable. Last but not least, just for recheck check for voltage drop calculation, though in HV systems it's not at all problem, but still I recommend to have a last check. I think you have never done cable sizing, but don't loose your hope..try it out! ------------------------------- Nothing is impossible!!

Find a piece of aluminum foil rated at 1 amp. Attach the foil on the end of the wire before the load. It will probably fry the foil, keep adding additional foil until foil stops failing. Add up how many pieces you have, that's your answer.