CompEx `d` - Flameproof Enclosure
Ex d type of protection is a type of protection in which the parts that can ignite an explosive atmosphere are placed in an enclosure that can withstand the explosion developed within the enclosure, and prevent the transmission of the explosion to the outside environment.
Area of usage:
- Zone 1 or Category 2 or EPL Gb
- Zone 2 or Category 2 or EPL Gc
- All gas groups.
Gaps in the enclosure
Since these enclosures are not hermetically sealed, all gaps, cover flanges, cable inlets and other places where a gas could enter or leave the enclosure are not to exceed these specified values:
- 0.1 mm with group IIC gases
- 0.15 mm with group IIA or IIB gases.
Threaded joints
The treaded part must be at least 8 mm long, with 6 threads of which 5 threads must be engaged.
Minimum distances to other objects next to the enclosure
These values will depend on the type of the hazardous gas potentially surrounding the enclosure:
| Group | Minimum distance |
|---|---|
| IIA | 10 mm |
| IIB | 30 mm |
| IIC | 40 mm |
Glands
All glands used for cable entry to an Ex `d` enclosure have to be Ex `d` or Ex `de` certified. A barrier gland may be required if one of these is true:
- Cable outside body not round (some old types of cables, usually not in use any more).
- Not a Compact Cable (some old types of cables, usually not in use any more).
- Hygroscopic fillers (some old types of cables, usually not in use any more).
- Group IIC gases.
- Group IIA and IIB gases and enclosure internal volume greater than 2 litres.
Ex `d` type enclosures are always made of metal, because of that there is no need for locknuts, serrated washers, IP washers, or shrouds of any type. Blanks used to cover any unused entry holes must be Ex `d` or Ex `de` certified!
