{"id":1453,"date":"2024-10-11T12:51:56","date_gmt":"2024-10-11T17:51:56","guid":{"rendered":"https:\/\/www.exitlightco.com\/blog\/?p=1453"},"modified":"2025-01-07T15:44:40","modified_gmt":"2025-01-07T20:44:40","slug":"understanding-nema-ratings-and-classes","status":"publish","type":"post","link":"https:\/\/www.exitlightco.com\/blog\/understanding-nema-ratings-and-classes\/","title":{"rendered":"Understanding NEMA Ratings &amp; NFPA 70 Classifications"},"content":{"rendered":"\n<p>NEMA ratings and Class 1 Division 1 and 2 ratings are two different systems used to classify enclosures or areas based on their environmental and safety requirements, particularly when it comes to protection against hazards. Here&#8217;s a breakdown of each:<\/p>\n\n\n\n<p><strong>NEMA Ratings<\/strong><\/p>\n\n\n\n<p>NEMA (National Electrical Manufacturers Association) ratings classify electrical enclosures based on their ability to protect against various environmental conditions. These ratings focus primarily on physical protection from dust, water, and other foreign objects. Examples of NEMA ratings include:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>NEMA 1<\/strong>: General-purpose indoor protection against dust and light.<\/li>\n\n\n\n<li><strong>NEMA 4<\/strong>: Protection against windblown dust and rain, splashing water, and hose-directed water; often used for outdoor applications.<\/li>\n\n\n\n<li><strong>NEMA 4X<\/strong>: Similar to NEMA 4, but also resistant to corrosion.<\/li>\n\n\n\n<li><strong>NEMA 6<\/strong>: Protects against occasional submersion in water.<\/li>\n<\/ul>\n\n\n\n<p>NEMA ratings generally do not specifically address hazardous or explosive atmospheres, though some enclosures may be suitable for use in such environments depending on their design.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity is-style-wide\"\/>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-9d6595d7 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:50%\">\n<figure class=\"wp-block-image size-large is-style-default\"><a href=\"https:\/\/www.exitlightco.com\/product\/LEDC1D2-R.html\"><img decoding=\"async\" src=\"https:\/\/www.exitlightco.com\/mm5\/graphics\/00000001\/LEDC1D2-R-1.jpg\" alt=\"\"\/><\/a><\/figure>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\"><\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:50%\">\n<figure class=\"wp-block-image size-large\"><a href=\"https:\/\/www.exitlightco.com\/product\/WLEX4X.html\"><img decoding=\"async\" src=\"https:\/\/www.exitlightco.com\/mm5\/graphics\/00000001\/WLEX4X.jpg\" alt=\"\"\/><\/a><\/figure>\n<\/div>\n<\/div>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity is-style-wide\"\/>\n\n\n\n<p><strong>Class 1 Division 1 and 2 Ratings<\/strong><\/p>\n\n\n\n<p>The Class and Division system is a method used by the National Electric Code (NEC) and similar standards to describe hazardous locations where explosive or flammable gases, vapors, or dusts might be present. The focus here is on the likelihood of an explosive atmosphere being present in an area.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Class 1<\/strong>: Refers to locations where flammable gases or vapors are present.<\/li>\n\n\n\n<li><strong>Division 1<\/strong>: The hazardous substance (gas, vapor, or liquid) is present continuously or frequently under normal operating conditions. The risk is high, and explosive atmospheres are expected to be present.<\/li>\n\n\n\n<li><strong>Division 2<\/strong>: The hazardous substance is only present in abnormal conditions (e.g., an accidental release or equipment malfunction). The risk is lower compared to Division 1.<\/li>\n<\/ul>\n\n\n\n<p><strong>Class 1 Division 1<\/strong> indicates a very high level of hazard since explosive or flammable gases are present most of the time. <strong>Class 1 Division 2<\/strong> indicates a lower level of hazard where the risk is only during abnormal conditions.<\/p>\n\n\n\n<p><strong>Key Differences<\/strong><\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Purpose<\/strong>:\n<ul class=\"wp-block-list\">\n<li><strong>NEMA<\/strong>: Focuses on environmental protection (dust, water, corrosion).<\/li>\n\n\n\n<li><strong>Class\/Division<\/strong>: Focuses on protection from hazardous or explosive atmospheres.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Hazardous Environment<\/strong>:\n<ul class=\"wp-block-list\">\n<li><strong>NEMA<\/strong>: Does not explicitly deal with explosive hazards.<\/li>\n\n\n\n<li><strong>Class 1 Division 1 and 2<\/strong>: Explicitly indicates the presence of explosive gases or vapors.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Use Cases<\/strong>:\n<ul class=\"wp-block-list\">\n<li><strong>NEMA<\/strong>: Suitable for non-hazardous areas and general protection.<\/li>\n\n\n\n<li><strong>Class 1 Division 1 and 2<\/strong>: Required for areas where explosive or flammable substances might be present.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n\n<p>In short, while NEMA ratings address protection against environmental factors, Class 1 Division 1 and 2 ratings focus on the safety of equipment in areas with explosive hazards. Equipment in hazardous locations often needs to comply with both NEMA and Class\/Division requirements.<\/p>\n\n\n\n<p><strong>NFPA 70 NEC Hazardous Locations Classes, Divisions and Groups<\/strong><\/p>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-9d6595d7 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:100%\">\n<div class=\"wp-block-group is-vertical is-layout-flex wp-container-core-group-is-layout-8cf370e7 wp-block-group-is-layout-flex\">\n<figure class=\"wp-block-table is-style-stripes has-small-font-size\"><table><thead><tr><th>cLASS<\/th><th>DIVISION<\/th><th>GROUP<\/th><\/tr><\/thead><tbody><tr><td>I &#8211; \u00a0Flammable gases or vapors may be present<\/td><td>1 \u2013 Ignitable concentrations of hazards exist under normal operation conditions and\/or where the hazard is caused by frequent maintenance or repair work or frequent equipment failure<br>2 \u2013 Ignitable concentrations of hazards exist under abnormal operation conditions<\/td><td>Group A \u2013 Acetylene<br>Group B \u2013 hydrogen, butadiene, ethylene oxide, propylene oxide and acrolein<br>Group C \u2013 Ethylene, cyclopropane and ethyl ether<br>Group D \u2013 Acetone, ammonia, benzene, butane, ethanol, gasoline, hexane, methane, methanol, methane, naphtha, natural gas, propane and toluene<\/td><\/tr><tr><td>II \u2013 Combustible dust may be present<\/td><td>1 \u2013 Ignitable concentrations of hazards exist under normal operation conditions and\/or where the hazard is caused by frequent maintenance or repair work or frequent equipment failure<br>2 \u2013 Ignitable concentrations of hazards exist under abnormal operation conditions<\/td><td>E \u2013 Combustible metal dusts: aluminum, commercial alloys and magnesium<br>F \u2013 Combustible carbonaceous dusts: carbon black, charcoal, coal and coke dusts<br>G \u2013 Other combustible dusts: Chemicals, flour, grain, plastic and wood<\/td><\/tr><tr><td>III \u2013 Easily ignitable fibers or flyings may be present<\/td><td>1 \u2013 Ignitable concentrations of hazards exist under normal operation conditions and\/or where the hazard is caused by frequent maintenance or repair work or frequent equipment failure<br>2 \u2013 Ignitable concentrations of hazards exist under abnormal operation conditions<\/td><td>N\/A<\/td><\/tr><\/tbody><\/table><\/figure>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n<p><strong>NFPA 70 NEC Zone Classification System<\/strong><\/p>\n\n\n\n<p>The Zone Classification System serves as an alternative to the traditional Class and Division system, offering an American adaptation of the International Electrotechnical Commission&#8217;s (IEC) Zone system. This approach retains the wiring methods and protection techniques outlined in the NEC (National Electrical Code). Zones categorize the type of hazardous material\u2014whether gas or dust\u2014and assess the likelihood of its presence in ignitable concentrations in the surrounding atmosphere. Unlike the Class and Division system, which focuses on normal versus abnormal conditions, the Zone system is based on how frequently the hazardous material is present.<\/p>\n\n\n\n<figure class=\"wp-block-table is-style-stripes\"><table class=\"has-fixed-layout\"><thead><tr><th colspan=\"2\">NFPA 70 NEC Hazardous Locations Zones<\/th><\/tr><\/thead><tbody><tr><th><strong>Gases, Vapors and Mists<\/strong><\/th><td>0 \u2013 Ignitable concentrations of flammable gases or vapors which are present continuously or for long periods of time<\/td><\/tr><tr><th><\/th><td>1 \u2013 Ignitable concentrations of flammable gases or vapors which are likely to occur under normal operating conditions; may exist frequently because of repair\/maintenance operations or leakage; or equipment is operated in a manner that equipment breakdown\/faulty operations could result in the release of ignitable concentrations of flammable gases or vapors and failure of the equipment<\/td><\/tr><tr><th><\/th><td>2 \u2013 Ignitable concentrations of flammable gases or vapors which are not likely to occur under normal operating conditions and if they do will only persist for a short period of time; or volatile flammable liquids, gases, or vapors are confined within closed containers\/systems and can escape only as a result of an accidental rupture; or volatile flammable liquids, gases, or vapors are normally prevented by positive mechanical ventilation, but may become hazardous due to system failure<\/td><\/tr><tr><th><strong>Dusts and Fibers\/Flyings<\/strong><\/th><td>20 \u2013 Combustible dusts or ignitable fibers\/flyings are present continuously or for long periods of time<\/td><\/tr><tr><th><\/th><td>21 \u2013 Combustible dusts or ignitable fibers\/flyings are likely to occur under normal operating conditions; or may exist frequently because of repair\/maintenance operations or leakage; or equipment is operated in a manner that breakdown\/faulty operations could result in the release of ignitable concentrations of combustible dust or fibers\/flyings and failure of the equipment<\/td><\/tr><tr><th><\/th><td>22 \u2013 Combustible dusts or ignitable fibers\/flyings are likely to occur under normal operating conditions; or may exist frequently because of repair\/maintenance operations or leakage; or equipment is operated in a manner that breakdown\/faulty operations could result in the release of ignitable concentrations of combustible dust or fibers\/flyings and failure of the equipment<\/td><\/tr><\/tbody><\/table><figcaption class=\"wp-element-caption\">Group defines the\u00a0type\u00a0of hazardous material and partly the\u00a0location\u00a0of the surrounding atmosphere .<\/figcaption><\/figure>\n\n\n\n<p><strong>NFPA 70 NEC Hazardous Location Groups<\/strong><\/p>\n\n\n\n<figure class=\"wp-block-table is-style-stripes\"><table class=\"has-fixed-layout\"><thead><tr><th>Group I<\/th><th>Group II<\/th><th>Group III<\/th><\/tr><\/thead><tbody><tr><td rowspan=\"4\">Mines susceptible to firedamp (flammable mixture of gases naturally occurring in a mine)<\/td><td>Explosive gas atmospheres other than mines susceptible to firedamp \u2013 Group II equipment is subdivided into three subgroups<\/td><td>Explosive dusts \u2013 Group III equipment is subdivided into three subgroups<\/td><\/tr><tr><td>A \u2013 Atmospheres containing acetone, ammonia, ethyl alcohol, gasoline, methane, propane, or gases\/vapors of equivalent hazard<\/td><td>A \u2013 Atmospheres containing solid particles and fibers greater than 500 microns that could be suspended in air and settle out<\/td><\/tr><tr><td>B \u2013 Atmospheres containing acetaldehyde, ethylene, or gases\/vapors of equivalent hazard<\/td><td>B \u2013 Atmospheres containing combustible dusts other than combustible metal dusts<\/td><\/tr><tr><td>C \u2013 Atmospheres containing acetylene, hydrogen, or gases\/vapors of equivalent hazard<\/td><td>C \u2013 Atmospheres containing combustible metal dusts<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<p><strong>Browse and Shop Harsh Environment Egress Lighting<\/strong><\/p>\n\n\n\n<div class=\"wp-block-buttons is-layout-flex wp-block-buttons-is-layout-flex\">\n<div class=\"wp-block-button\"><a class=\"wp-block-button__link wp-element-button\" href=\"https:\/\/www.exitlightco.com\/category\/harsh-environment-exit-signs.html\">Exit Signs<\/a><\/div>\n\n\n\n<div class=\"wp-block-button\"><a class=\"wp-block-button__link wp-element-button\" href=\"https:\/\/www.exitlightco.com\/category\/harsh-environment-combination-exit-sign-emerency-lights.html\">Combo Exit Signs<\/a><\/div>\n\n\n\n<div class=\"wp-block-button\"><a class=\"wp-block-button__link wp-element-button\" href=\"https:\/\/www.exitlightco.com\/category\/HarshEnvironment-Emergency-Lights.html\">Emergency Lights<\/a><\/div>\n<\/div>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>NEMA ratings and Class 1 Division 1 and 2 ratings are two different systems used to classify enclosures or areas based on their environmental and safety requirements, particularly when it comes to protection against hazards. Here&#8217;s a breakdown of each: &hellip; <a href=\"https:\/\/www.exitlightco.com\/blog\/understanding-nema-ratings-and-classes\/\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":9,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[117],"tags":[123,122],"class_list":["post-1453","post","type-post","status-publish","format-standard","hentry","category-informational","tag-classes","tag-nema"],"_links":{"self":[{"href":"https:\/\/www.exitlightco.com\/blog\/wp-json\/wp\/v2\/posts\/1453","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.exitlightco.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.exitlightco.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.exitlightco.com\/blog\/wp-json\/wp\/v2\/users\/9"}],"replies":[{"embeddable":true,"href":"https:\/\/www.exitlightco.com\/blog\/wp-json\/wp\/v2\/comments?post=1453"}],"version-history":[{"count":6,"href":"https:\/\/www.exitlightco.com\/blog\/wp-json\/wp\/v2\/posts\/1453\/revisions"}],"predecessor-version":[{"id":1466,"href":"https:\/\/www.exitlightco.com\/blog\/wp-json\/wp\/v2\/posts\/1453\/revisions\/1466"}],"wp:attachment":[{"href":"https:\/\/www.exitlightco.com\/blog\/wp-json\/wp\/v2\/media?parent=1453"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.exitlightco.com\/blog\/wp-json\/wp\/v2\/categories?post=1453"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.exitlightco.com\/blog\/wp-json\/wp\/v2\/tags?post=1453"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}