EE WAS LOADING 10'X11/2' CONDUIT ON A PIPE RACK,EE OVER LOADED ONE SIDE OF THE RACK, THE RACK HAD NOT SHOE PLATES & THE LEGS SANK IN THE DIRT CAUSING THE RACK TO FALL OVER. THE EE WAS STRUCK BY THE CONDUIT KNOCKING HIM OVER. HE PUT HIS LEFT ARM OUT TO BREAK THE HIS FALL & LANDED ON HIS WRIST. THE INCIDENT OCCURRED AT GROUND LEVEL