Schneider Electric Push Buttons

Maintaining NEMA 4 Rating When Making Enclosure Penetrations

Cutouts are very common when modifying enclosures for push buttons, indication lights, conduit entries or mounting hardware. Cutting into an enclosure runs the risk of eliminating the protective nature of the NEMA rated attributes. Proper steps must be followed in order to preserve the NEMA rating of an enclosure.

Devices mounted to the enclosure must have the same NEMA rating as the enclosure. 

This means that if the devices are installed to the manufacturer's specifications, they will be able to maintain the NEMA rating of the enclosure. 

Water tight conduit hubs must be used when running wire through a cutout in an enclosure. 

There are many different types of conduit hubs that are used to secure conduit to an enclosure. However, only certain conduit hubs are rated for a watertight seal. By using water tight hubs, the NEMA rating of the enclosure is maintained.

Bonded washers are necessary when mounting hardware to an enclosure.

If standard mounting hardware is used, the NEMA rating of the enclosure will no longer be maintained. Bonded washers have rubber gaskets that make a watertight seal around the drilled hole. It is also important to make sure the material used for the bonded washer matches the material of the enclosure. Stainless steel enclosures require stainless steel bonded washers.