EWEB has this weird situation where they classify some 480V services as "primary" on Schedule 32 if the customer owns the transformer, but other 480V services as "secondary" on Schedule 31. Both are fed from the same 12.47kV distribution but one gets a 3% discount and one doesn't. Has anyone else seen utilities make this distinction based on transformer ownership rather than actual voltage level?
Eugene Water & Electric - Confusing Voltage Classifications
Alabama Power does something similar. If you own the transformer dropping 13.2kV to 480V, you're on Rate LPM with discounts. If they own it, you're on Rate LMS at higher rates even though your service voltage is identical. It's really about who bears the transformer losses and maintenance costs.
Wisconsin Public Service has the same approach. The logic is that customer-owned transformers eliminate distribution losses the utility would otherwise absorb. So they pass some of those savings back as voltage discounts. It's not really about voltage level - it's about system efficiency and cost allocation.