A connection box assembly comprising a connection box having a proximal end shaped to receive a fastener and a distal end, spaced in the lateral direction from the proximal end, having a stop and a slide. The assembly may include a spacer shaped to be inserted, without the use of tools, within the slide until the spacer abuts the stop. The spacer may be adjustable in length. The spacer may be arranged to extend from the proximal end of the connection box in the transverse direction when inserted into the slide and abutted against the stop.