I am back feeding a 45 kva transformer, which only feeds a 30 hp 460v air compressor. I spoke with Square D, they said the inrush on itial start up may trip the breaker and reccomend oversizing by at least 125% if not more. Can I legally use a # 8thhn on a 225 amp c.b., to feed this 45kva transformer (208 pri to 460v sec) which feeds a 40 amp time delay fused disconect on the secondary side to feed the 30hp 460v compressor, all three phase. If not why. Article 240-101 seems to indicate yes but not by more than 3 times.