Got a weird one here in Savannah. Commercial customer on Georgia Power Schedule GSA-6 had one phase go dead due to transformer failure. Utility replaced the transformer and fixed the dead phase, but now the multiplier seems off. Customer's kWh usage jumped 40% even though production is same as before. CTs are marked 800:1, meter programming shows 800:1, but something doesn't add up. Anyone seen multiplier errors after dead phase situations? Pamela W.
Dead Phase on Three-Phase Meter - Multiplier Still Wrong
Pamela, check if they changed the meter during the repair. Sometimes they'll swap in a different model that reads the CT secondary differently. Had a similar case with KU where the old meter read 5A secondary and new one expected 1A but nobody updated the programming. Catherine D.
Also verify the CT connections weren't rewired incorrectly during the repair. Dead phase situations often require rewiring work and it's easy to cross CT leads or change polarity. The 40% increase suggests the meter is now reading one phase twice or there's a wiring error multiplying the signal. Get Georgia Power to do a full meter test with CT burden measurements. Randy D.
Randy you nailed it! Turns out during the transformer replacement they had to rewire the CT cabinet. One of the CTs got connected to two different meter inputs while the third input was getting no signal. Meter was essentially doubling one phase and ignoring another. They fixed the wiring and usage dropped back to normal. Thanks for the insight! Pamela W.
This is exactly why I always insist on witnessing any major electrical work on customer accounts. Duke Energy here in Cincinnati has had several wiring errors during emergency repairs. The crews are under pressure to restore power quickly and metering accuracy isn't always the priority. Janet K.
Great catch Pamela. Had a similar issue with Dominion Energy in Richmond after storm damage repairs. Customer's demand charges went through the roof because the demand multiplier was wrong even though energy was reading correctly. Always check both energy and demand multipliers separately. Don S.