Throughout any Ex inspection campaign non-compliant issues are going to be found. Here are some common issues we have found whilst conducting inspections on Intrinsically Safe equipment

• Incorrect Zone (Zone 2 for Ex Ex ic; Zones 1 and 2 for Ex ib; Zones 0, 1 and 2 for Ex ia)

• Incorrect Group for hazardous area classification

• Incorrect Temperature Classification for hazardous area classification

• Incorrect ambient temperature range for environment

• Documentation missing or incorrect

• Certificate of Conformity not read

• Labels missing or not illegible

• No separation of IS and Non-IS circuits

• Entity calculations not checked correctly or incorrect values used

• Barriers swapped out and IS calculations not re-checked

• No dedicated IS earth/bar

• Earthing missing from Galvanic / Zener barriers

• Uncertified or incorrectly certified barriers installed in the hazardous area and no Conformity Assessment Document

• Screens not earthed at one end (preferable in the Non hazardous area) and not secured in terminals in the hazardous area

• Not correct maintenance

• Testing done with 230 VAC

• Inspection not focusing on Ex installations outside of hazardous area

• Ex i devices built into a U certified Ex d box

• Unauthorized modification on Ex i circuit

• Human failures, misuse

What others can you think of?

Source: with some addings.

Keep up good work!


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