THE MUCK CAR WAS DUMPED AT THE ROTARY DUMP. WHEN THE HOIST OPERATOR STARTED OUT OF THE ROTARY DUMP THE HOIST WOULD NOT MOVE. THE CONTRACTED ELECTRICIAN CAME OUT AND LOOKED AT IT. HE TIGHTENED UP SOME CONTROL LEADS IN THE VFD AND THE HOIST OPERATED. AT THIS TIME HE CHECKED ALL ELECTRICAL CONNECTIONS TO INSURE THAT THEY WERE TIGHT.