Abstract: An apparatus includes first and second struts, each of which defines a channel and has an open side. The struts together define a juncture at which one of the struts crosses the other. First and second electrical contacts engage busbars in the channels. Wires interconnect the first electrical contacts with the second electrical contacts. A housing contains the wires. The housing has a first elongated portion reaching along the open side of the first strut in a direction from the first electrical contacts toward the juncture, a second elongated portion reaching along the open side of the second strut in a direction from the juncture toward the second electrical contacts, and a corner at which the first and second elongated portions meet in vertical alignment with the juncture.