Lest it come out funny, or lest someone thought I was being sarcastic, I didn't word it as "Where in the world are you?" Perhaps I could have asked, "Where on the globe are you?"
There was a post recently where the sub-synchronous speed of induction motors was being discussed; confusion arose because the OP didn't mention he was in a 50 Hz location, but the responders were thinking 60 Hz.
I'm curious as to whether the applicable laws in the US vary state to state . . .
CR
"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]
Your local Fire Dept., AHJ, and insurance underwriter may have a problem with it..... I'd check with them first.
Have you looked at a dry-type solution? It may be more cost effective than an oil-filled trans. when you consider all the mitigation that may be necessary.
I wouldn't recommend oil-filled inside. The fire suppression due diligence and insurance paperwork would be a nightmare. I'd look at two 3-4 MVA dry-types. The manufacturers may be able to do a 7.5MVA dry-type too. Better lead time with dry-type as well I believe.
It's a fire code issue, so you'll have to get some help or check with local fire marshal. You may be required to install in a room with fire-rated walls. With FR3, you may get away without the vault, but it depends on the building type, occupancy, and interpretation of local authority.
Oil vs dry choice depends on a lot of factors. Outside oil-filled would be much simpler from an a fire code standpoint. Have you looked into lead times? They are crazy right now.
