Answer:
They must be enclosed in explosion proof housing or general-purpose housing (as per NEC Regulations)
Explanation:
It is important to know what are Class I, Division 1 and 2 locations.
Class I: includes those industries or places where flammable gases exists and there are chances of explosions.
Division 1: Those places where hazard can happen under normal operating conditions
Division 2: Those places where hazard can happen under abnormal conditions.
The conventional relays, contactors and switches cause arcing when they operate and this is a completely normal phenomenon but with respect to these categories, it is very dangerous to operate such electrical devices without any precaution.
Therefore industries are required by the regulatory authorities to install explosion proof housing to enclose conventional relays, contactors and switches to avoid any explosion or hazard. General-purpose housing can also be used given that it follows the regulations provided by the NEC or any other regulatory authority.
