NEMA 7 enclosure design, third party certification, standards, and field modifications

In today´s safety and cost conscious environments, a stronger emphasis is being placed by manufacturers of NEMA 7 enclosures to design products with a broader range of hazardous locations applications, and time saving, field modifiable features. With these new design issues comes a renewed effort at third party testing authorities to upgrade existing modifications, develop new testing procedures for higher ratings and expanded certifications for greater field flexibility. This paper explores the design criteria of NEMA 7 enclosures from a manufacturer´s viewpoint, how third party certifications and testing standards apply, and end user concerns for labeling, certifications, and field modifications