Haunting a house is bad form, but stealing electricity from the rightful residents seems to be going way too far.  The London "Independent," December 6, 1994 (via Newspapers.com):

Heol Fanog House in St David's Without, near Brecon in Wales, has plagued its occupants since they moved in five years ago. Self-employed artist Bill Rich, his wife Liz and three young children, have endured smells of sulphur and church incense, shadowy figures and ghostly footsteps. Their first quarterly electricity bill was £750; electricity is somehow consumed even when the family is away and all the appliances are off. They reckon they had been charged about £3,000 for electricity they hadn't themselves used. The house made the children edgy and the parents listless.

The Riches called in the medium Eddie Burks, who said he found the highest concentration of evil he had ever come across, which was feeding off electricity for its own power. It was also taking it from the family. The electricity board tested the meter twice and found it to be working correctly with no abnormal fluctuation.

Apparently, the Rich family was troubled by various sinister manifestations until they finally fled the house in 1995.  Subsequent residents did not report anything unusual, which just shows that you can never tell with poltergeists.

via Newspapers.com

This Fortean mystery comes from the "Great Falls Tribune," August 4, 1957:

Tulsa, Okla--Mr. and Mrs. C. V. Wilkinson and their 12-year-old daughter packed their belongings and moved out of the house they claim is "haunted" by an electrical phenomenon.

"I'm about to crack up," Mrs. Wilkinson said. "I wish someone would come forward and tell us what's causing all this."

The family thought their troubles had ended after Wilkinson, an oil company employee, dug up water pipes around the house and removed a new metal fence he believed responsible for creating a magnetic field.

The family slept in their car after tables and chairs went on a weird "dance" and overturned. They are puzzled as to what's causing electrical plugs to blow up without being connected, a sweeper to go on an aimless course through the house, and various household articles to start hopping around.

The "mystery" has damaged their $1,300 electrical organ, caused the refrigerator motor to blow out twice and knocked the clock from its shelf six times.

Wilkinson said be had lived on the property for 23 years without prior incident, until this month. "We don't know if the thing is a magnetic field, uranium, an old gas pocket under the ground, or what," said Wilkinson, "but it has us completely unnerved and so upset we can't live a normal life here. We're moving."

An August 4 article in the "Springfield Daily Leader" added a particularly creepy detail:  One night, the Wilkinson daughter came into her mother's room complaining that the sweeper was "crawling over her stomach."  When Mrs. Wilkinson went into the girl's bedroom, she saw that the sweeper's extension cord had been wrapped around the bed several times, and the vacuum itself was sitting on the bed, apparently waiting for someone to tuck it in for the night.

Unfortunately, I couldn't find any more about the Wilkinsons, so I'm unable to say if the "electrical phenomenon" was ever explained.