It may have taken 18 months, but the state Public Utilities Commission has finally pulled the plug on a humming backyard electric transformer that a Cerritos man says kept him awake at night.
Replacement of the unit, which converts high-voltage electricity to 110 volts for Davis' home and about 20 neighbors, ended a year-and-a-half-long dispute between him and electric company.
The noisy single-phase distribution unit was installed behind Davis' Rusty Fig Circle home in April 2009 after a circa-1976 GE transformer began leaking oil. The replacement, a pad-mounted Howard Industries-brand transformer, emitted a loud whine, which Davis said resembled the sound of a refrigerator laboring on a hot summer day.
When the 60-year-old retired postal worker complained, Edison workers replaced it with a different Howard Industries transformer.
But that one hummed nonstop too, although not quite as loudly as the one it replaced, Davis said.
When he complained again, Edison officials returned with a sound meter and declared that the third transformer was operating within accepted industry noise standards.
Although electric transformers have no moving parts, they can hum because of vibrations created by the magnetically generated elongation and contraction of their internal core. Davis asserted that the transformer hum could be heard inside his house.
"It was 13 feet from the head of my bed," he said. "At 2 in the morning, when everything else was quiet, it woke you up. They basically said I'd have to live with it, that there wasn't anything else they could do for me."
Davis, who used a guitar to determine that the hum was the sound of a musical B note, took his complaint to the PUC after that.
During a September hearing, the power company argued that the backyard transformer's noise level was within the normal range, about 45 decibels. They said the device could be removed or replaced, but it would have to be at Davis' expense.
Although a transformer costs about $2,400, installation of a "non-standard" transformer would cost Davis $17,990, a company representative testified.
In its findings, the PUC noted that the "pervasive low-tone hum of the replacement transformer is a disturbing nuisance" to Davis and his family.
"There is no evidence regarding whether the GE transformer was reparable, but to replace it with a transformer of lesser quality is clearly a degradation of service," the commission ruled.
"The fact that the Howard unit meets minimum noise standards is irrelevant in this instance. . . . After 33 years of quiet, to be told that a similar quiet unit costs $17,990 is unreasonable."
Since his transformer was replaced, Davis said, Edison workers have swapped out a similarly noisy transformer on a nearby street.
The power company said the PUC's ruling in Davis' case played no role in the replacement of the neighbor's transformer, however.
"It's not a precedent-setting order," company spokesman Steve Conroy said last week. "It doesn't apply to everybody who complains a transformer is noisy."
He said decisions to swap transformers are made on a case-by-case basis. "We treat each customer individually," Conroy said.
Mississippi-based Howard Industries remains on Southern California Edison Co.'s list of approved equipment suppliers, he said.