We have a manufacturing client in Portland with a new 480V service installed last month. Duke Energy used 400:1 CTs but I'm seeing consumption that suggests they should be 200:1 based on the load profile. Bills are running about $18K/month on Schedule LGS-1 when I expected closer to $35K. Duke is refusing to test the meter setup saying "new installs are always correct." Anyone dealt with this before? - Kira J.
CT Ratio Wrong on New Install - Duke Energy Won't Test
Kira, this is unfortunately common with new service installs. First, double-check the nameplate on the CTs themselves - sometimes the work order says one thing but field crews install what's on the truck. You have the right to request meter testing under most state PUC rules. In Tennessee, we cite Rule 1220-4-4-.12 for commercial meter accuracy disputes. Check Oregon's equivalent regulations. Document everything and escalate to Duke's commercial services manager if the local office won't cooperate. The math you're describing definitely warrants investigation. - Randy D.
Had this exact situation with Ameren Missouri two years ago. New 800A service, they installed 800:1 CTs instead of 400:1. Took three months and a formal complaint to get them to test. When they finally did, sure enough the multiplier was wrong from day one. Got a $47,000 refund going back to service start. Keep pushing Earl S.
Check the CT secondary wiring too. Sometimes the CTs are correct but wired to the wrong meter terminals. I've seen installers cross phases or miss the B-phase entirely on three-phase setups. That would also give you the lower readings you're seeing. - Cliff H.
In North Carolina, Duke has to test within 10 business days if you put the request in writing and cite NCUC Rule R8-13. Don't let them blow you off. I had a similar case in Charlotte where the multiplier was programmed at 0.5x instead of 2.0x in their AMI system. Completely wrong direction but same net effect - artificially low bills. - Karen W.
What's the actual demand reading showing? If you're seeing like 200kW demand when you should have 400kW, that's a dead giveaway the CT ratio is doubled. Idaho Power tried to tell me once that "lower bills should make customers happy" until I pointed out the true-up would be painful. - Warren T.
Update: Finally got Duke to agree to test after I filed a complaint with Oregon PUC. They found the CTs were actually 400:1 as installed, but the meter multiplier was programmed for 800:1. So I was getting billed for half the actual usage. Three month true-up bill was $31,000. Client wasn't happy but at least we caught it early. Thanks everyone! - Kira J.