iiee Correction factors for cable size com.

British Standard 7671.

We use NEC (National Electrical Code) in the US as a standard. I am not familiar with IIEE. There are publications by IEEE (Institute of Electrical and Electronic Engineers) in the US regarding cable size and current-carrying capacity (here referred to as "ampacity").

Cable size with regard to ampacity is rather complex. It is a thermodynamic system and there are several variations of installations. Most code books rate single conductors in free air, no more than 3 conductors in conduit, etc. Then there are tables to de-rate for more than 3 conductors, higher ambient temperatures, etc.

Hope you find what you're looking for.

We use NEC (National Electrical Code) in the US as a standard. I am not familiar with IIEE. There are publications by IEEE (Institute of Electrical and Electronic Engineers) in the US regarding cable size and current-carrying capacity (here referred to as "ampacity").

Cable size with regard to ampacity is rather complex. It is a thermodynamic system and there are several variations of installations. Most code books rate single conductors in free air, no more than 3 conductors in conduit, etc. Then there are tables to de-rate for more than 3 conductors, higher ambient temperatures, etc.

Hope you find what you're looking for.

Thanks but if its ok to you an you still send me the table for derating more than three conductors cause here in dubai the authority had guidelines here in computing cable sizes and according to my analyzation their having 1:2 ratio for KW:A (rating of MCCB) on main feeders etc. the max ambient air temperature here was 48-52 deg. and using an electricity supply voltage of 230/400V ±10%,50Hz,3phae 4wire and seperate neutral protective con.) and can you tell me if theres any difference in british and us standards accoeding to electrical codes.

May I refer you to this chart and others: Okonite web page showing NEC table, and this page by PowerStream showing charts, calculators for voltage drop, etc.

What you need is available on the world-wide web, so Google it.

You can find the answer here: http://www.electricsmarts.com/ Check my blog for other e-learining sites: http://philipjarina.blogspot.com/