cable size!

[johnmf]

hey wonder if anybody could shed any light on this please. got a brand new miller welding set. its 3 phase and the maximum current demand is 128A ( big i know)!!. its wired straight off an isolator and the cable is 4 core with each cores csa being 10mm, the engineer told me that this was the standard cable fitted. does this sound a bit undersized to anyone else or is it just me?

 

[Lectrician]

When you say 128amp - is this "welders talk" for the output?

If not, is this 128amp per phase, or total? If 128amp is the total of the 3 phases, the load will be around 40amp a phase, and 10mm *will probably* be ok.

More info needed.

 

[industryspark]

itl not be welders talk for output no,

thats the current the set requires, it will be 128amp across the 3 phases. does seem a bit small to me.

 

[Steve]

thats the current the set requires, it will be 128amp across the 3 phases. does seem a bit small to me.

tiny.

 

[RF Lighting]

got a brand new miller welding set. its 3 phase and the maximum current demand is 128A ( big i know)!!.

If spread across 3 phases, that is 42.67A per phase.

its wired straight off an isolator and the cable is 4 core with each cores csa being 10mm,

What sort of cable is it?

I'm going to assume SWA. If this is the case, 10mm² 4c SWA has a current carrying capacity of 58A when installed to reference method 1, or 62A when installed to reference method 11 or 13.

the engineer told me that this was the standard cable fitted. does this sound a bit undersized to anyone else or is it just me?

Providing there are no derating factors to take into consideration, the length of the run does not result in excessive volts drop, and the Zs value is not too high (which the maximum permitted Zs value for a 45A, type D, BS EN 60898 MCB is just 0.22 ohms)

Then yes a 10mm² is acceptable.