Gordon C. here from Santa Clarita. Got a manufacturing client on SCE's TOU-GSD-A rate with a 480V service and 400:1 CTs. Been seeing weird demand readings that don't match the energy consumption patterns. Turns out one phase went dead about 3 months ago but the meter kept applying the full 400x multiplier to the remaining two phases. Anyone else seen this create billing errors? The kW demand was showing artificially low while kWh seemed high for a dead phase situation.
Dead phase causing multiplier confusion on TOU-GSD-A account
Greg L. in Atlanta. Yeah we see this with Georgia Power accounts too. When you lose a phase, the demand calculation gets screwy because it's not registering the imbalance properly on older electromechanical meters. The multiplier stays the same but the actual load distribution changes. Did you check if SCE has AMI data that might show the phase loss timing?
Randy Dawson here. This is a classic case where the meter multiplier is technically correct, but the underlying measurement is wrong due to the dead phase. The 400:1 CT ratio should still apply, but you're only getting readings from two phases instead of three. Most utilities will do a field inspection if you can document the timeline of when consumption patterns changed. Have you pulled 12-15 months of interval data to show the change point? Also, check if there are any demand coincident factors in the TOU-GSD-A tariff that might need adjustment for this situation.
David K. from Charlotte. Had similar issue with Duke Energy on a Schedule LGS account. The dead phase lasted 6 weeks before we caught it. Duke actually credited back the demand charges because the meter was essentially mis-measuring during that period. The multiplier was right but the input was wrong. They used the energy consumption pattern to back-calculate what demand should have been.
Tony F. in Vegas. NV Energy gets really picky about these situations. They want documentation from a licensed electrician showing when the phase failed and when it was restored. The multiplier adjustment isn't automatic - you have to request it and provide proof. Also make sure you check if the voltage transformers were affected. Sometimes VT issues compound the CT problems.
Update from Gordon C. - SCE agreed to do a field investigation. The dead phase was confirmed from their AMI data starting July 15th. They're reviewing 3 months of billing for potential adjustment. Apparently this happens more often than they admit, especially in summer when phase loading gets unbalanced. Thanks for the advice everyone.
Lee B. from Rochester. Question - when they do the billing adjustment, do they pro-rate the multiplier or recalculate the whole demand profile? We've got a similar situation brewing with RG&E and I want to know what to expect.
Lee B. - in our case SCE recalculated the demand based on the energy profile and applied a 2/3 factor for the two good phases. The multiplier stayed 400:1 but they adjusted the raw readings. Ended up with about $3,200 credit over three months. The key was having the AMI data to prove exactly when it happened.
Christine L. from Minneapolis. Xcel Energy has a specific form for this - Request for Meter Investigation due to Phase Loss. Might be worth checking if SCE has something similar for future reference. The form helps document everything they need upfront.
Dan W. in Fresno. PG&E dragged their feet on a similar case for 8 months. Sometimes you need to escalate to the state PUC if the utility won't cooperate. Document everything and keep pushing. The multiplier errors from dead phases are legitimate billing errors they have to fix.