Electrical Control Enclosures
Control enclosures are used to house electronic equipment are often listed with ratings. These ratings standardize enclosure performance and identify the enclosure’s ability to resist external environmental influences.
NEMA, CSA, and UL Control Enclosures
In North America, NEMA, CSA, and UL are the commonly recognized standards organizations. UL and CSA both require enclosure testing by qualified testers in certified labs. They send site inspectors to ensure a manufacturer adheres to established manufacturing methods and material specifications. NEMA does not require independent testing and compliance is determined by the manufacturer.
NEMA Enclosures for For Hazardous Locations
Type 7 and 10 enclosures are designed to contain an internal explosion without causing an external hazard. Type 8 enclosures are designed to prevent combustion through the use of oil-immersed equipment. Type 9 enclosures are designed to prevent the ignition of combustible dust.
- Type 7 Enclosures: Constructed for indoor use in hazardous (classified) locations classified as Class I, Division 1, Groups A, B, C, or D.
- Type 8 Enclosures: Constructed for either indoor or outdoor use in hazardous (classified) locations classified as Class I, Division 1, Groups A, B, C, and D.
- Type 9 Enclosures: Constructed for indoor use in hazardous (classified) locations classified as Class II, Division 1, Groups E, F, or G.
- Type 10 Enclosures: Constructed to meet the requirements of the Mine Safety and Health Administration.
IEC Control Enclosures
The IEC (International Electrotechnical Commission), which is a worldwide organization for standardization, established the IP (Ingress Protection) rating system. Like NEMA, IEC does not require independent testing and leaves compliance and up to the manufacturer. Unlike NEMA ratings, IEC IP ratings do not specify fabrication practices, corrosion protection, or risk of explosion.
Content on this page was created using excerpts from the Power Transmission Handbook (5th Edition), which is written and sold by the Power Transmission Distributor’s Association (PTDA). The Power Transmission Handbook is just under 400 pages and is a valuable resource for anyone involved or interested in the power transmission industry.