Certain Devices Such As Lighting Fixtures, Motors, Control Stations and Receptacles Are “Factory Sealed”.
The Manufacturer Builds Into Their Product a Sealing Method Which Complies With the Requirements of the Code.
These Devices Are Typically Marked “Seals Not Required”
Rule 18-118 Lighting Fixtures, Class I, Zone 1
(1) Fixtures for fixed and portable lighting shall be approved as complete assemblies in accordance with the requirements of Rule 18-100 and shall be clearly marked to indicate the maximum wattage of lamps for which they are approved.
(2) Fixtures intended for portable use shall be specifically approved as complete assemblies for that use.
(3) Each fixture shall be protected against physical damage by a suitable guard or by location.
(4) Pendant fixtures shall be:
(a) Suspended by and supplied through threaded rigid conduit stems, and threaded joints shall be provided with set screws or other effective means to prevent loosening; and
(b) For stems longer than 300 mm, provided with permanent and effective bracing against lateral displacement at a level not more than 300 mm above the lower end of the stem, or provided with flexibility in the form of a fitting or flexible connector approved for the purpose and for the location not more than 300 mm from the point of attachment to the supporting box or fitting.
(5) Boxes, box assemblies, or fittings used for the support of lighting fixtures shall be approved for the purpose and shall comply with the requirements of Rule 18-100.
Rationale for Rule 18-118.
Lighting fixtures contain two possible sources of ignition: the hot lamp surface and, should the lamp break, a hot filament that will burn out, producing a combination of intense heat and a spark. For this reason, this Rule requires all lighting fixtures for use in Class I, Zone 1 locations to meet the requirements of Rule 18-100.
Intent for Rule 18-118
We intend that lighting fixtures be approved as complete assemblies because if any part, including the lamp, is changed, the heating characteristics of the fixture may change and the maximum surface temperature of the fixture may be exceeded. Some fixtures are approved with a number of different globes and a number of different corresponding lamps. This information is then clearly marked on the fixture or the accompanying instructions, and it is the installer's responsibility to ensure that the completed assembly is approved. Most Class I fixtures have a connection chamber separated from the lamp chamber by a seal, and therefore qualify for the factory-sealed exemption.
Electrical Safety Authority