Not sure about EUSERC in Arizona, I did a little checking on my POCO web site but found nothing. As far as service size, we still go by what the city/county approves. Just did a 100 a few weeks ago with no issues. Arizona has 16 different power companies, some of which are co-ops and some are tribal owned. In my area I work mainly with Tucson Electric Power which is a Unisource company.