PRIOR TO ACCIDENT I HAD A CONVEYOR SHUT DOWN ON THE WASH PLANT. CHECKED IT OUT, COULD NOT GET IT TO RESTART SO ASKED INJ EE TO HELP ME GET IT RESTARTED.INJ EE PROCEEDED TO TEST THE VOLTAGE GOING TO THAT CONVEYOR WHICH IS NORMAL PROCEDUREHE WAS CHECKING IT GOING FROM 1 CONNECTOR TO THENEXT & SUDDENLY THERE WAS A FLASH EXPLOSION CAUSING AN ELECTRICAL BURN TO EE'S RIGHT HAND & ARM