stray losses is the total machine losses except total copper loss(field winding,armature wind,tr coils).so it is
hysterisisloss+windage losses+egddycurrent losses
+frictional losses.....etc
The max. load can appeared across the cable indicates the max.current
is flowing through it.so with the increase of load causes sufficient
incriment in cable insulator. so cable insulator detemines the size.