Old Sparky is the Electric Chair from The Green Mile. It is used at Cold Mountain Penitentiary to execute criminals that have been committed of gruesome murders or sexual attacks. It is located E Block Death Row, where Paul Edgecomb works. It´s located at the end of The Green Mile (The stretch of Block E that leads to the execution Chamber), in the execution chamber.
The process is simple. The prisoner and the guards enter the execution Chamber, and the prisoner is strapped into the seat with bands and clamps. Once fully strapped in, the officers will start to recite The Execution Speech to the Prisoner. After the prisoner makes a final statement, his head is masked with the customary hood. Then, a sponge is soaked, and placed inside the chair´s plug, which is then attached to the prisoner´s head (To conduct electricity to the brain with out setting the prisoner on fire). After that, the Officers will finish the Execution Speech, and once the clock strikes the Execution Time, the Officer orders the executioner to throw the switch. The prisoner will then be zapped with 15,000 volts. The electrified sponge will knock out the prisoner three seconds after the switch is thrown, providing a painless death for the prisoner. The power will stay on for 60 seconds. After that, the prisoner´s heartbeat will be checked. If it´s stopped, then the Prisoner is dead, and the execution is over. If it is still working, the process will be repeated, and will be as much as possible, until the prisoner is proclaimed dead. Once the Prisoner is dead, they will carefully take off the prisoner´s straps and plugs. The body will then be sent away to a funeral home with a hearse.