If any one got a ballast they cant use because not residental standard US voltage, I can use them as I have step up transformer
To do 480 volt ballast up to 1000 watts
277 volt is welcome and so is 208 volt ballast.
I will let u know if Interested when u post those ballast.
Here is a 277v F20T12 choke ballast that could be used to run a 18w SOX lamp satisfactorily:
https://www.ebay.com/itm/254804624868