Not sure if there's an additional certification, but it would not surprise me at all that an electrician here would not want to work on a home with an unusual setup that they're not particularly familiar with.

Electricians specialize. Resi guys do residential and rarely to never handle 3 phase. I do commercial and light industrial because heavy industry isn't around here and I despise doing resi work. Three phase is usually run everywhere by the power co and a transformer (pole pig) converts to single phase near the residence.

There isn't. But residential electricians are specialists. Then there are commercial and industrial ones, etc, etc.