Using 40 k for 30k transformer

[Good guy]

I’m doing the AC side of a solar job, engineer did not know we had a high leg service. We are using solar edge it needs a neutral. We ended up getting a transformer I’m figuring everything will change wire size size of AC disco on Primary side. Engineer was taking for ever to give me new set of plans. So I did the wire calc and disconnect myself thanks to mike holts videos. I sized it for a 40k. The engineer finally gets back at me and said he sized the wire for a 30k and 100 amp disconnect. I know there is something about 25 foot tap rule. My question is can you use a bigger transformer 40k and still use the wire size for a smaller Transformer 30k on the Primary side. I know on the secondary I can size to my load thank you. For give my spelling

 

[augie47]

As long as the conductor is protected at it's ampacity you can use a larger transformer.
Depending on the particulars, there is probability of inrush current problems.