NBC "Fear Factor" contestants shocked themselves as they ran through wires hooked to a California substation and alarmed utility companies across America.

NBC had permission from Southern California Edison to hook wires to the 10,000-volt Redondo Beach substation, a network spokesman told the New York Daily News.

NBC said the reality TV show contest, which shocked participants grabbing flags as they ran the maze in Monday night's show, was designed and supervised by an electrical engineer.

However, electrical utility companies across the country complained.

"Substations are not playgrounds. They can be potentially dangerous to untrained individuals," a New York Con Ed spokesman told the newspaper. "Stunts of any kind around electricity and electrical devices should not be imitated."

In response to utility company complaints, NBC added two viewer advisories about electrical dangers.