Restricted breathing equipment is constructed such that the enclosure will restrict the entry of gases, vapors and mists.
Restricted breathing enclosures may be used where:
- the enclosure contains sparking contacts but with limitation of dissipated power so that the average internal air temperature does not exceed the external air temperature by more than 10 K, or
- the enclosure does not contain sparking contacts and the limitation is for external surface temperature (typically luminaires).
Equipment certified using this protection method is suitable for use in Class I, Zone 2.