Kent L. from Sioux Falls. Got a weird situation with Xcel Energy AMI meter. Restaurant client's bills dropped 40% after AMI installation in September, but usage patterns didn't change. Suspected dead phase on three-phase service. How do you diagnose CT problems on AMI meters?
AMI Programming Error - Three Phase Dead Leg
Randy here. Dead phase is common issue with AMI installs when CTs aren't properly connected. Can you access the meter's phase-by-phase readings? Most AMI systems show individual phase data that would reveal a zero or very low reading on the dead phase.
Randy - Xcel's online portal doesn't show phase detail to customers. I called and requested phase readings, but they said everything looks normal. Restaurant owner says equipment usage hasn't changed but kWh dropped from 8,500 to 5,100 monthly.
Karl D. in Lincoln. Kent, I deal with Xcel Nebraska frequently. They'll provide phase data if you submit formal written request as the customer's representative. Email their large customer service group. Also check if they changed the CT ratio during AMI conversion.
Steve B. Tulsa here. Had restaurant with dead phase that ran for 6 months before discovery. The giveaway was unbalanced motor operation and higher maintenance costs. Customer didn't connect it to lower electric bills initially.
Steve - that's exactly what's happening! Restaurant owner mentioned ice machine and walk-in cooler acting up since September. Getting phase data from Xcel tomorrow.
Karen B. from Green Bay. Kent, also have them check CT polarity. Seen cases where one CT installed backwards causes partial cancellation instead of complete dead phase. Results in similar 30-40% usage drop.
Update: Got phase readings from Xcel. Phase B showing zero amps while A and C normal. Xcel scheduled service call to check CT connections. Will update when resolved.
Ernest M. in Spokane Valley. Kent, curious about the resolution timeline. Restaurant equipment damage from single-phasing can be expensive if it runs too long.
Ernest - Xcel found loose CT connection on Phase B. Fixed same day and usage jumped back to normal 8,500 kWh range. Restaurant equipment seems okay, just ran inefficiently for 2 months. Getting credit for under-billed usage of about $800.