IEC 60079-11:2023/ISH4:2025

INTERNATIONAL ELECTROTECHNICAL COMMISSION
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IEC 60079-11
Edition 7.0  2023-01
Explosive atmospheres -
Part 11: Equipment protection by intrinsic safety “i”

INTERPRETATION SHEET 4
This interpretation sheet has been prepared by subcommittee 31G: Intrinsically-safe apparatus,
of IEC technical committee 31: Explosive atmospheres.
The text of this interpretation sheet is based on the following documents:
DISH Report on voting
31G/425/DISH 31G/430/RVDISH
Full information on the voting for the approval of this interpretation sheet can be found in the
report on voting indicated in the above table.

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IEC 60079-11:2023 (Edition 7.0)
EXPLOSIVE ATMOSPHERES – Part 11: Equipment protection by intrinsic safety “i”
Background
The table of changes for IEC 60079-11:2023 (Edition 7) states:
Where two diodes are used in a safety shunt for Level of Protection “ia”, the failure of only a
single diode has been extended to the failure of a single shunt path. This means that the
tracking from the diode to reference voltages (for example, ground) no longer have to be
infallible.
ICS 29.260.20
IEC 60079-11:2023-01/ISH4:2025-09(en)

IEC 60079-11:2011 (Edition 6) 8.7.1 states:
Where diodes or Zener diodes are used as the shunt components in an infallible shunt safety
assembly, they shall form at least two parallel paths of diodes. In Level of Protection “ia” shunt
safety assemblies, only the failure of one diode shall be taken into accou
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