We are building a small NEMA 4X control enclosure to be installed in a C1D2 area. All of the internal components will have a C1D2 rating (thin client, power supply, some terminal strips). Since all of the components are rated accordingly, we are using a "general purpose" enclosure. The heat load/dissipation calcs I have performed theoretically show the enclosure will maintain an acceptable internal temperature; however, I'd prefer to add a vent to allow it to breath. Am I allowed to add a vent? The vent I am looking at using is AMVENT4XLG. We would add two of these on the low-side and high-side of the enclosure.