IEC 60079-35-1:2011 pdf – Explosive atmospheres – Part 35-1: Caplights for use in mines susceptible to firedamp – Generalrequirements -Construction and testing in relation to the risk of explosion
IEC 60079-35-1:2011 pdf – Explosive atmospheres – Part 35-1: Caplights for use in mines susceptible to firedamp – Generalrequirements -Construction and testing in relation to the risk of explosion.
5.1.2 Battery enclosure
The battery enclosure shall be tested in accordance with 81 to 8.3. In addition the battery enclosure shall meet the following requirements:
The pressure above atmospheric Inside the battery enclosure and the cells shall not exceed 30 kPa (0.3 bar) except that in sealed cells, a higher pressure is permissible, but each cell shall then be either provided with a pressure relief device or with the means to limit the pressure to a value which can be contained by the cell, as specified by the manufacturer.
Unless the caplight manufacturer can demonstrate that the concentration of hydrogen in the free volume of the battery enclosure cannot exceed 2 % by volume, the degassing apertures of all cells shall be so arranged that escaping gases are not vented Into any enclosure of the equipment containing electrical or electronic components or connections.
The cable between the battery enclosure and the headpiece enclosure shall have a sheath which is resistant to fatty acids and fire.
The cable sheath shall be tested for resistance to fatty acids in accordance with 8.6.
The cable sheath shall be tested for resistance to fire in accordance with 8.7.
For cable entries, each cable and its anchoring device shall comply with the tensile strength test according to 8.8.
One strand of the caplight cable shall:
a) when tested in accordance with 85, not ignite the methane and air mixture, or
b) be shown by calculation, or reference to cable data, not to exceed 450 °C under short circuit condition with its overload protection in place
Where overcurrent protection according to Clause 6 is provided wholly or partly by a fuse. each individual strand of each cable conductor shall be capable of either:
c) carrying the currents specified in 6.2b) without melting within the time specified (when tested without a fuse In circuit): or
d) carrying the currents specitied In 6.2b) without melting before the luse has ruptured (when tested with a fuse in circuit).
Where the requirement is satisfied by testing with a fuse in circuit, only the particular type of fuse used for the test shall be permitted for use in the caplight.
5.3 External charging contacts
Caplights which are recharged by means of external contacts shall Include a mechanical or electrical device preventing the withdrawal of current other than In accordance with 5.9 during the use of the caplight. When the electrical device is not an infallible component (as defined In IEC 60079-11, Components on which intrinsic safety depends). it shall be duplicated and each component shall be rated such that the maximum battery-charging current Is not more than two-thirds of the rated current for the component.
5.4 Internal electrical connections
Other than spring contacts for filament lamps, internal electrical connections shall conform to IEC 60079-7, Factory connections. Only the manufacturer’s recommended method(s) of making electrical connections to filament lamps shall be used
5.5 Solid electrical insulating materials
Solid electrical Insulating materials shall conform to IEC 60079-7. Solid electrical Insulating materials.
5.6 Internal wiring
Internal wiring shall conform to IEC 60079-7, Wiring internal to apparatus.
5.7 Supply of electrical power to other equipment
Where the caplight is also used to supply electrical power to other equipment (internal or external to the caplight) the other equipment shall not affect compliance with this standard and shall comply with an appropriate type of protection and equipment protection level (EPL),
Where the other equipment is external, the connection facilities to that equipment shall meet the requirements of IEC 60079-0, Connection facilities and terminal compartments or Supplementary requirements for plugs and socket outlets and connectors.
The EPL f the interlace shall be clearly identified in the documentation.
5.8 Creepage and clearance distances
All wiring connections and printed wiring boards which can affect the type of protection afforded shall be considered to have infallible separations if they meet the following creepage and clearance requirements:
– IEC 60079-7, Clearances and IEC 60079-7. Creepago distances: or
— 0,5 mm through solid insulation; or
— 0,5 mm under a conformal coating which shall seal the path between the conductors in question against the ingress of moisture and pollution, and shall give an effective lasting unbroken seal. It shall adhere to the conductive parts and to the insulating material. If the coating is applied by spraying, two separate coats shall be applied.
A solder mask alone is not considered as a conformal coating, but can be accepted as one of the two coals when an additional coat is applied, provided that no damage occurs during soldering. Other methods of application require only one coat, for example dip coating. brushing, or vacuum impregnating. A solder mask that meets the requirements of a Type I coating in accordance with IEC 60664-3 is considered as a conformal coating and an additional coating is not required.