Last edit: 06/08/2025
When dealing with products suitable for an ATEX atmosphere, you need to bear in mind that there are 5 types:
- Component: Ex Components, such as empty enclosures or terminals, having only an Ex-Component Certificate, marked with the suffix “U”, cannot not be used in the hazardous area. A component must become an Equipment to be able to be installed in a classified area
- Equipment: Ex-Equipment is suitable for installation in a classified area, but they must be installed and used within the electrical ratings for power, voltage, current, frequency, duty, and such other characteristics where non-conformity might cause the installation to become an ignition hazard.
- Simple Apparatus. They are passive components for example switches, junction boxes, resistors and simple semi-conductor devices that do not need an Ex marking. However Simple apparatus shall be clearly identifiable by durable labelling. Labelling for simple apparatus is normally made by the manufacturer.
- Assembly: it’s a pre-manufactured combination of Ex Equipment and Ex Components, together with other items, that are electrically or mechanically interconnected and , that are pre-assembled prior to being placed into service at the end-user site.
- Excluded components. There are products that are excluded from the Atex product Directive since they are not considered a source of ignition. For example, stairs, manual tools like hammers or manual valves.
The other key concept is that, with the exception of simple apparatus, only Ex Equipment having an Ex Equipment certificate can be used inside a classified area.
Please bear in mind that an Ex Equipment assembly may have portions of the equipment assembly with different explosion protection specifications. For example a portion of the equipment assembly might require EPL Gb (Zone 1) with the remainder as EPL Gc (Zone 2), or a portion of the equipment assembly might require EPL Gc (Zone 2) with the remainder as non-hazardous.
The other important aspect is that the classified zone can be “external” to the assembly or generated by the assembly itself. In other terms, there are two aspects of area classification that can impact equipment assemblies. These aspects are:
- A potential source of release external to h the equipment assembly, or
- A potential source of release associated with the equipment assembly.
The standard IEC 60079-46: 2017 details how to assess and certify Assemblies.