calculating cable size

[cooter]

hi, i was wondering as i calculate the cable size of a run of swa do i use the total ampage or the line ampage? for example my run is 95 meters and total current is 273 amp. the cable is spaced in horizontal cable tray.

 

[Paul.M]

Welcome to the forum Cooter.

 

[telectrix]

hi, i was wondering as i calculate the cable size of a run of swa do i use the total ampage or the line ampage? for example my run is 95 meters and total current is 273 amp. the cable is spaced in horizontal cable tray.

far more info required. is this 3 phase or single phase?

 

[Simonslimline]

hi, i was wondering as i calculate the cable size of a run of swa do i use the total ampage or the line ampage? for example my run is 95 meters and total current is 273 amp. the cable is spaced in horizontal cable tray.

As tel has mentioned, nowhere near enough info to help you to be honest.

 

[cooter]

hi telectrix, thanks for your reply. it's a 3 phase supply of 400v, the temperature will be no more than 30 degrees and i would like to keep voltage drop down to as little as possible. it will be protected back at the board

 

[Darkwood]

What load do you require here, whenever you say an ampage and 3ph, it is usually assumed that its per phase.

You state 273amp so are we to take that as 273amps per phase, I ask because coincidently 273 is divisible by 3 so I rather suspect you only looking at a 3ph supply 91amps?

Like others have said, you haven't given anything like the info required here, everything for the nature of the load to achieving discrimination between devices all may change a cable sie by many factors.

If you can draft up some calcs so we can see roughly what your trying to work out here as oppose to pages of drip fed info, it may save some time.

 

[Spoon]

Any more info Cooter?

 

[Flanders]

Sounds like a homework question You will need to Know the total KVA of what you are supplying

 

[N6rul]

Need more information mate to help...like above...