PN-Series NEMA 4X Boxes Bud Industries PN-Series NEMA 4X Boxes are designed to IP65 of IEC 529 and NEMA 1, 2, 4, 4X, 12, 13 specifications. These enclosures also pass UL508-4X requirements. Most models have internal guide slots for mounting PCB assemblies vertically. Some versions offer internal bosses to allow horizontal mounting of PCBs. The wall mounting holes and cover-attaching screws are outside the sealing area, preventing ingress of moisture and dust. The M-4 stainless steel, non-magnetic cover screws fasten into threaded brass inserts. The covers are sealed with a silicon gasket.