An electrical connector includes a housing, a first terminal, and a first lock. The housing includes a first receiving chamber and first recess positioned adjacent to the first receiving chamber. The first terminal is insertable into the first receiving chamber. The lock is securable to the housing and includes a horizontal base plate, a first pressing rod extending downward from the horizontal base plate and insertable into the first receiving chamber to press against the first terminal, and a first rotation prevention member extending downward from the horizontal base plate and insertable into the first recess to mate with the recess in a substantially gapless manner.