Equipment protection levels (EPLs), equipment categories and area certification markings for zone classified locations

The markings for hazardous area equipment present a challenge to professionals dealing in the international engineering arena. The markings can be confusing, and with standards continually revised, can be a challenge to keep up-to-date. The introduction of equipment protection levels and ATEX categories have made markings even more challenging to those who are not familiar with the IEC requirements or the ATEX European Union directives. ATEX refers to two separate (but related) European Union (EU) Directives: 2014/34/EU (replaced 94/9/EC) — Equipment Directive — primarily concerned with trade and the manufacture and sale of Ex equipment, and 1999/92/EC — Use Directive — primarily concerned with the safety of workers and applies to the Classification of Hazardous Areas and the correct selection, installation, inspection and maintenance of Ex equipment. Though markings for equipment certified under IEC requirements, the ATEX directive [1], Articles 505/506 of the US National Electrical Code (NEC) [2], and Section 18 of the Canadian Electrical Code (CEC) [3] may all seem similar, there are differences between them. The purpose of this paper is to 1) identify the Equipment Protection Levels and what they mean, 2) identify the ATEX categories and how they relate to the EPLs and 3) examine these different marking systems.