THE ACFT COLLIDED WITH A STEEL SUPPORTING CABLE ATTACHED TO A POWER LINE POLE DURING A GO-AROUND (MISSED APPROACHED). IT WAS A DARK NIGHT WITH VARYING DEGREES OF VISIBILITY NEAR THE GROUND DUE TO FOG. THERE WERE TWO PLTS ON BOARD THE ACCIDENT ACFT BUT THE ONE DOING THE ACTUAL FLYING OF THE APPROACHES WAS NOT QUALIFIED FOR NIGHT FLYING AND WAS NOT INSTRUMENT RATED. BOTH PILOTS REPORTED HAVEING MADE 4 APPROACHES TO LAND BUT IN EACH CASE VISUAL CONTACT WAS LOST AND A GO-AROUND INITIATED. THEY HAD DECIDED TO TRY ANOTHER ARPT WHEN THE COLLISION WITH THE CABLE OCCURRED. ALT AT IMPACT WAS ABOUT 6 FT AGL. THE LEFT WING HAD STRUCK THE CABLE AND STARTED TO BURN. DURING THE GROUND SLIDE OF 235 FT THE LEFT WING AND FIRE SEPARATED FROM THE ACFT AND ALL OCCUPANTS EGRESSED WITH MINOR INJURIES. THE ACCIDENT LOCATION WAS ABOUT 1.5 MILES FROM THE ARPT. AT IMPACT THE ACFT WAS IN A LEFT BANK AND DESCENDING AT ABOUT 500 FT A MINUTE.