Volt Drop trouble

[James Sutton]

Hi ALL

Have to install a Condenser unit on a roof in the nxt couple of weeks the length of run is around 50M the unit FLC is 24A will be Reference method E on Try for most of the run 4mm swa can take 41A table 4D4A and 6mm can take 53A. Just need some advice regarding VoltDrop

As this is supplying a Computer Room and needs to be spot on

Any Help
Thanks
JS

 

[matt12321]

mv/a/m x lb x L divide 1000

for 4 mm

mv/a/m = 11
lb = 24a
L = 50m

11x24x50/1000 = 13.3 v dropped

which is just above the 5% tolerance for low voltage installations

6mm u should be ok

i hope im right now lol

 

[Denatone]

Assuming you're running 2 core single phase SWA your volt drop should be from table 4D4B
VD for 4mm would be 13.2V or 5.74% - not acceptible
VD for 6mm would be 8.76 V or 3.81% - acceptible.
use 6mm or find a shorter route (it will be under the 5% tolerance for a run of less that 40m)

 

[davelerave]

not that familiar
but as well as the VD at FLA i'd check the 'startup amps' and the max VD for startup