CMI JBP75175 14" x 12" x 8" Black Plastic 3-Hole Swimming Pool Junction Box. CMI’s Thermocraft Swimming Pool Light Junction boxes are UL Listed to those rigorous standards. UL established a separate category and Standard just for weatherproof boxes that are designed to connect wires from the electrical panel to the swimming pool light. This Standard is much stricter than typical weatherproof boxes. The Thermocraft Box uses a Brass Terminal Bar with Stainless Steel screws, while competitors use cheaper aluminum bars with mild steel screws.