IEC 60079-1-2014 pdf free download
IEC 60079-1-2014 pdf free download.Explosive atmospheres – Part 1: Equipment protection by flameproof enclosures“d”.
Electrical equipment with flameproof enclosure d” shall be one of the following:
— level of protection “da” (EPL “Ma” or “Ga”);
— level of protection “db” (EPL “Mb” or “Gb”); or
— level of protection dc” (EPL “Gc”).
The requirements of this standard shall apply to all levels of protection unless otherwise stated.
4.2 Requirements for level of protection “da”
Level of protection ada” is only applicable to catalytic sensors of portable combustible gas detectors.
The following are the additional specific requirements for level of protection “da” that modify or supplement the requirements of this standard:
— the maximum free internal volume shall not exceed 5 cm3
— the electrical conductors into the sensor shall employ a sealed joint, in accordance with Clause 6, directly in the wall of the enclosure;
— the breathing device of the sensor shall comply with Clause 10, and shall be bonded to the wall of the enclosure so as to eliminate any gaps (such as cementing per 6.1 or sinter bonding) or shall be press-fitted to the wall of the enclosure with supplemental mechanical means of securing (such as swaging);
— supplied by a circuit of Level of Protection “ia”, with a maximum dissipated power limited to 3,3 W for Group I and 1,3 W for Group II and
NOTE catalytic elements operate normally at a high temperature. If the power dissipation is increased beyond normal operating levels, the element fails to an open circuit. Therefore, the required power limitation provides a limitation of the external surface temperature.
— the non-transmission tests of 15.3 or 15.4.4 (if applicable) are modified to increase the number of non-transmission tests as shown in Table 1.
4.3 Requirements for level of protection “db”
Other than specific requirements for level of protection wdan and dc”, all other requirements of
this standard shall apply to level of protection “db”.
4.4 Requirements for level of protection “dc”
4.4.1 General
The requirements for level of protection “dc” are applicable to electrical equipment and Ex components with electrical switching contacts and are found in 4.4.2 through 4.4.3.
4.4.2 Construction of “dc” devices
4.4.2.1 General
The requirements of 4.4.2.2 through 4.4.2.5 replace those of Clause 5 through Clause 13. For equipment in level of protection “dc” that is intended for connection to field wiring, Clause 13 applies.
4.4.2.2 Free internal volume
The free internal volume shall not exceed 20 cm3.
4.4.2.3 Seal protection
Enclosures for level of protection dc that do not serve as the external equipment enclosure shall be capable of withstanding normal handling and assembly operations without damage to seals. When the enclosure for level of protection dc also serves as the external equipment enclosures, the enclosure requirements of lEG 60079-0 apply.
4.4.2.4 Continuous operating temperature (COT) requirements
Poured seals and encapsulating compounds shall have a continuous operating temperature (COT) range that includes a minimum temperature that is below, or equal to, the minimum service temperature and a maximum temperature that is at least 10 K above the maximum service temperature.IEC 60079-1 pdf download.
