Larger cable or not,

086lavey

Wiring a new wearhouse for a customer , job nearly finished, was asked to move a 3ph welding socket in to the new wearhouse , the new run will be 40mts max from new sub board , which is fed by a 5 by 10sq swa , the point im been asked to move is protected by a 3ph 16amp D type mcb at the moment, the rest of the welding points are wired in 5by 2.5 nymj, would this new point be ok to wire in 5by 2.5 again or should i up grade to 5by 6sq for the longer run , this new point willl be not used much , as was told :rolleyes:

Randyleprechaun

Whats the max load of the welder. You'll need to know that to calculate!!

you could say 16A at 40Mtrs, seeing as it's a 16A MCB. It's probably actually less!!

I would say 6mm2 might be overkill but I'll work it out tomorrow if someone else doesn't first.

4mm2 might be ok!!!

Bruthal

The 16a breaker is what you would go by for circuit minimum size. 2.5 sq would do for that, but the length of the run as well as the 10 sq sub main may need to be taken into account. So 4 sq would be the size probably, and as said, the welder is probably a bit below the 16 amps too.

086lavey

Thanks for replys , did not get chance to look at welder , will do in the morning , the suply to the sub board is not in yet , i can change that to 16sq its not that long of a run ,

Mike2006

As I work it out, 3-phase @ 16 amps = 2.5mm2 would suffice at 120ft so 4mm2 is plenty.

Mike.

Randyleprechaun

By my calculations:

At 16A load, 2.5mm2 would be good enough all though might be a bit tight for volt drop. 4mm2 would do up to 60M at 16A load.

At an assumed load of 12A(assuming welder might be only 12A), 2.5mm2 would do up to about 50M and 4mm2 would do up to about 80M.

Hope this helps