Dynamic elaboration on the Art & Science of Hazardous Area Protection
General marking as per IEC 60079-7
These requirements supplement and modify the marking and instruction requirements of
IEC 60079-0 which are applicable also to Type of Protection increased safety ”e”.
The Level of Protection “eb” or “ec”, shall be shown as the Level of Protection.
Electrical equipment shall be additionally marked with the following:
a) rated voltage, along with rated current or rated power. If multiple voltage, current or power
ratings apply, and all of these ratings are not marked, then only the maximum ratings are
required to be marked with the complete rating details shown on the certificate;
For equipment or Ex Components effectively operating at other than unity power factor,
both current and power ratings are marked.
b) for rotating electrical machines in Level of Protection “eb”, the starting current ratio IA/IN
and time tE;
c) for measuring instruments with current-carrying parts and for current transformers, the
value of short-circuit current ISC;
d) for luminaires, the technical data of the lamps to be used, for example, electrical rating
and, if necessary, the dimensions;
e) for general purpose connection or junction boxes, the rating expressed as either
– the rated maximum dissipated power, or
– the set of values comprising for each terminal size, the permissible number and size of
conductor and the maximum current;
f) restrictions in use, for example use in clean environments only;
g) the characteristics of special protective devices where required, for example for
temperature control or for arduous starting conditions, and special supply conditions, for
example for operation only with a converter;
h) for batteries in accordance with IEC 60079-7 SEc.5.6: type of construction of cells,
number of cells and nominal voltage,
rated capacity with the corresponding duration of discharge.
i) for Ex Component terminals:
– the conductor range,
– the rated voltage;
Where marking space is insufficient, this information may appear in the instructions.
As the Type of Protection “e” ratings can be different from the industrial ratings, such
ratings should be segregated to the extent possible.
j) for resistance heating devices and resistance heating units to which the additional
requirements of 5.8 apply, the operating temperature.
IN case of INCREASED SAFETY CONCEPT additional measures are applied to increase the level of safety, thus preventing the possibility of high temperatures and the occurrence of sparks or electric arcs within the enclosure or on exposed parts of electrical equipment
Definition: Equipment protection by increased safety “e” is applied to electrical apparatus in which additional measures are applied & employed so as to give increased security against the possibility of excessive temperatures and of the occurrence of arcs and sparks in normal service or under specified abnormal conditions
In an INCREASED SAFETY equipment (assembly) , all components have their own individual Ex Certificates . The added advantage is the use of non-metallic enclosures in this protection scheme.
The only limitation is the EXCLUSIVE use of Ex Certified components which, most of the time , are available in limited power ratings.Industrial components are not permitted to be installed directly inside an Ex e certified enclosure.