Certification, intrinsically safe electrical

In 1936, the first certificate was issued in Great Britain for an intrinsically safe electrical device which was not designed for application in mining operations. 

Certification. It is a benefit to the employer to ensure that the intrinsically safe electrical circuit is certified. Certification can be achieved through the use of a third party, such as Underwriters Laboratories or Factory Mutual Research. Both of these organizations have their own standards for approval which are based on NFPA 493. The certification is accomplished in three steps ... 

Not all of the apparatus inserted in an intrinsically safe circuit need to have a certificate. This is based on the fact that, e.g., a terminal, a plug-and-socket connector or even a contact sparking in normal operation will not cause a risk if the electrical circuit is intrinsically safe. 

This certificate is issued for the electrical apparatus Intrinsically Safe Field Bus System RS 485... 

As a rule, they are installed in the safe area as associated apparatus. They are used to limit the electrical values for sensors, actuators etc. located in the hazardous area to levels permissible for intrinsic safety. A certificate is required each time. 

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