There is a cartoon character, Reddy Kilowatt, who for years has appeared as an affable and innocent symbol for the nation's privately held utilities. Lately he has been showing up in strange roles - as a purse snatcher, panhandler, simpleton and gambler.

Reddy's creator and image-keeper, Reddy Communications, Inc., is not pleased with this turn of affairs and yesterday won a temporary federal court injunction to protect Reddy's reputation. Judge Howard F. Corcoran prohibited - at least temporarily - the Environmental Action Foundation from publishing caricatures debasing Reddy.

It's all part of a skirmish between investor-owned utilities and the foundation, a nonprofit public interest group that has opposed the power companies on a wide range of consumer and environmental issues.

Reddy is now used by more than 150 utilities in advertisements boosting nuclear power and asking positions on environmental issues. Since last December, the foundation has printed unflattering portrayals of Reddy in their publications, including "The Power Line."

The reason, says Richard Morgan, head of the foundation's utility project, is that "Reddy Kilowatt is a devious representative of the industry, he's doing their dirty work . . . He is a symbol of economic subversion."

Not so, says Louise Bender of Reddy Communications, "Reddy has always been a very positive character and a symbol of good-will." Asked why Reddy filed suit, she said. "We felt they were giving Reddy a negative character."