Key Findings
- Intrinsically safe (Ex i) circuits are associated with the color light blue under IEC/EN 60079-14.
- The standard does not mandate all Ex i cables to be blue but requires that, if color is used for identification, it must be light blue.
- Inspectors can require inspectability of connections but cannot mandate blue cables and glands if other compliant identification methods exist.
- Use of tape or boots is not directly prohibited, but they must not prevent inspection or be used to modify gland fit.
- Cable bends are regulated by minimum bending radius, not by fixed angle requirements such as 45°.
Confirmed Facts
- IEC/EN 60079-14 addresses installation of electrical equipment in explosive atmospheres. It specifies that intrinsically safe (Ex i) circuits must be clearly identifiable. If color identification is used, the required color is light blue. The same restriction applies regardless of whether the Ex i circuit is instrumentation, communication, or other applications. Light blue must not be used for non-Ex i circuits to avoid confusion.
- In practice, Ex i cables and glands are often manufactured in blue or with blue components. However, commercially available ATEX-certified cables and glands are also sold in black. Inspectors cannot legally demand that all such equipment be replaced with blue versions, provided the installation ensures clear identification of Ex i circuits by other means.
- Inspectors are authorized to demand that connections remain inspectable. IEC/EN 60079-14 requires an initial inspection, and IEC/EN 60079-17 governs periodic inspections. Covering terminations with tape or boots is not explicitly banned, but if it blocks inspection or hides possible conductor damage, inspectors can require removal for verification.
- The standards explicitly prohibit using tape, heat-shrink, or similar materials to adjust cable diameters to fit glands. Cable glands must be matched to the actual cable dimensions as supplied. Using fillers or improvised coverings to modify fit is not compliant. Shrouds or boots may be used only if permitted by the manufacturer and without hindering inspection or causing accumulation of moisture or corrosion.
- Regarding cable routing, IEC/EN 60079-14 and related guides impose requirements for mechanical protection and minimum bending radii. Common values cited in practice are eight to twelve times the cable diameter, depending on construction. The standard does not prescribe fixed angular rules such as “45° loops.” Angles of 90° are not prohibited if the minimum bending radius and mechanical integrity are respected.
- Reports indicate that some inspectors criticized the use of black Ex i cables and the covering of stripped sections with tape, but such criticisms are not grounded in direct ATEX wording. They reflect inspection practice emphasizing inspectability and avoidance of confusion, not explicit mandatory rules. Statements that “ATEX requires 45° cable loops” are not documented in the standard.
Sources
Published by Leonardo Tomás Cardillo
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