Found what looks like a current transformer ratio error at a pharma facility in Michigan. Consumers Energy has been using 400:1 CTs for billing but the actual transformers installed are 800:1. This means they've been under-billing by 50% for the past 4 years! Customer is freaking out about the potential back-billing. Anyone dealt with CT ratio disputes with Consumers?
Consumers Energy - CT ratio error at pharmaceutical plant
Tina - that's a significant error but it works both ways. If Consumers made the mistake, they typically can't back-bill more than 12 months in Michigan. Check the meter installation records and make sure you have photos of the actual CT nameplates. The customer might owe money, but not 4 years worth.
Randy, that's exactly what I'm hoping. The customer definitely didn't know about the error - they're not electrical people. I've got photos of the CT nameplates clearly showing 800:1. Now I need to find out who installed them wrong and when. If it was Consumers' mistake, the back-billing should be limited.