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Correct installation
For the installation of electrical systems in areas with explosive gas atmospheres of group II, rule IEC 60 079-14 (EN 60079-14) will apply.
Electric circuits of protection types d, e, q, o, m, p
Installation in the panel is identical to ”standard” installation, however the pro-
cedures for connecting Ex equipment must be followed. This refers, for example to voltage, current, fuses and motor protection equipment, etc. The require-
ments for specific products must be taken from their corresponding test certifi-
cates, standards and prescriptions as well as from the guidebook. It is only permitted to work on electric circuits within the Ex-area (for example when connecting to Ex-e terminal box if the voltage has been switched off). An Ex-e terminal box should only be opened after the voltage has been switched off.
Electric circuits of protection type „i“ (intrinsically safe)
For the planning and operation of switchgears and control systems installed in the safe area, but which contain circuits leading into the Ex-area, certain requirements should be considered. This applies especially to intrinsically safe circuits. Intrinsically safe circuits and non-intrinsically safe circuits should be kept separate. Minimum distances (distances) between bare connections must be observed, the cables must not produce any inadmissible external induc-
tance or capacitance. The maximum admissible electrical limits of Ex-i equip-
ment must be observed at all times. Intrinsically safe and non-intrinsically
safe electrical circuits should not cross, however it is allowed between two in-
trinsically safe circuits. Intrinsically safe circuits must be clearly marked.
Intrinsically safe circuits are marked by a „light blue“ color. This color is re-
commended for all intrinsically safe circuits to prevent confusion and/or linking up to a non-intrinsically safe circuit. Examples: cabels, cables, cable conduits, dampers, connection boxes, cable connectors,...
A minimum distance of 50 mm should be allowed between intrinsically safe and non-intrinsically safe circuits, and a minimum distance of 6 mm between two different intrinsically safe circuits. During installation the cables of intrinsically safe and non-intrinsically safe circuits should be laid out separately!
Suggestion on how to create a pannel
It is necessary to keep intrinsically safe and non-intrinsically safe equipment separate. It is recommended, in this case, that a sufficient distance be kept, to avoid extra costs in the future.
Large transformers, frequency rectifiers, large relays and other electric equip-
ment that may influence intrinsically safe circuits by inductance or capacitance should be installed at a sufficient distance. As a precaution Ex-i equipment should have a suitable cover to protect it from incorrect handling. The appro-
priate standards and regulations must be observed.
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