INJURED EE WAS ASSISTING COWORKER WITH INSTALLING A PLATFORM BRACE IN THE PREHEATER STRUCTURE. THE BRACE WAS ATTACHED TO A STEEL CABLE CHOKER. ATTACHED TO HOISTING CRANE. AS THE BRACE WAS BEIN G HOISTED INTO POSITION TO BE BOLTED INTO PLACE, A CONNECTION CLIP ATTACHED TO THE BRACE BECAME CAUGHT UP UPON EE'S FALL PROTECTION LANYARD CAUSING HIM TO FALL. FALL STOPPED BY FALL PROTECTIO