A-Series™ Panelboards. Pro-Stock, Unassembled Lighting Panels. Main Breaker Kit. Interior Type: AQU3: 208/120 VAC, 3 Phase. Breaker not included except for .WB. kits (where product number ends in .WB.). .WB. kits include a breaker, mounting kit and load-side lugs. Rating plugs must be ordered separately. Note: 400A and 600A breaker kits cannot be used for sub-feed applications in Pro-Stock panelboards. To achieve 6 poles of subfeed, the MB233WB or MB233 kit is also required. 6 poles of subfeed only work with 400A and 600A interiors.