A junction box assembly includes an upper cover coupled to a lower cover assembly. The upper cover has a jump start terminal housing and a first through hole which accommodates a jump start terminal. The lower cover assembly includes a fuse assembly having an upper case and a lower case configured to hold a bus bar unit having a plurality of fuses. The upper case includes a collar and a first drain hole. The collar defines a second through hole and is concentric to the jump start terminal. The first drain hole is spaced apart from the fuses. The first drain hole is open to a second hole of the bus bar unit. The lower case includes a second drain hole open to the second hole. Accordingly, water is routed through the fuse assembly and away from the fuses so as to retain the functionality of the junction box assembly.