A device that will not generate or store more than 1.2 V, 0.1 A, 25 mW, or 20 ìJ. Examples are switches, thermocouples, light-emitting diodes, connectors, and resistance temperature detectors (RTDs). Apparatus reliant on voltage or current limiting or suppression devices for remaining within the limits given in the definition, and sensors (e.g. certain gas detector sensors) that utilize catalytic reaction or other electrochemical mechanisms are excluded by IEC 60079-11 from the category of “simple apparatus”. Temperature limitations as described in 4.2 are applicable to simple apparatus.
Source: API Recommended Practice 14FZ, Recommended Practice for Design, Installation, and Maintenance of Electrical Systems for Fixed and Floating Offshore Petroleum Facilities for Unclassified and Class I, Zone 0, Zone 1, and Zone 2 Locations, Second Edition, May 2013. Global Standards
Electrical component or combination of components of simple construction with well-defined electrical parameters which is compatible with the intrinsic safety or energy-limited safety of the circuit in which it is used.
Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global Standards