EMPLOYEE STATED THAT HE WAS USING THE PIPE BENDER CONDUIT FOR COMMUNICATION LINES AT 1-NORTH SHAFT. AFTER HE HAD BENT THE CONDUIT HE KNEELED DOWN TO BEGIN STRIPPING WIRES AND FELT PAIN IN HIS LOWER BACK. HE STATED HE LAYED ON THE GROUND ATTEMPTING TO STRETCH OUT AND IT DIDN'T HELP.