2.2.1
Interior
Enclosures to house equipment in an interior environment shall meet the
requirements of NEMA 250 Type 12.
2.2.2
Exposed-to-Weather
Enclosures to house equipment in an outdoor environment shall meet the
requirements of NEMA 250 Type 4X.
2.2.3
Corrosion-Resistant
Enclosures to house equipment in a corrosive environment shall meet the
requirements of NEMA 250 Type 4X.
2.2.4
Hazardous Environment Equipment
All system electronics to be used in a hazardous environment shall be
housed in a metallic enclosure which meets the requirements of paragraph
"Hazardous Environment."
2.3
TAMPER PROVISIONS
Enclosures, cabinets, housings (other than environmental camera housings),
boxes, raceways, conduits, and fittings of every description having hinged
doors or removable covers, and which contain any part of the CCTV equipment
or power supplies, shall be provided with cover operated,
corrosion-resistant tamper switches, arranged to initiate an alarm signal
when the door or cover is moved. Tamper switches shall be mechanically
mounted to maximize the defeat time when enclosure covers are opened or
removed. The enclosure and the tamper switch shall function together to
not allow direct line of sight to any internal components and tampering
with the switch or the circuits before the switch activates. Tamper
switches shall be inaccessible until the switch is activated; have mounting
hardware concealed so that the location of the switch cannot be observed
from the exterior of the enclosure; be connected to circuits which are
under electrical supervision at all times, irrespective of the protection
mode in which the circuit is operating; shall be spring-loaded and held in
the closed position by the door cover; and shall be wired so that they
break the circuit when the door or cover is disturbed. Tamper switches on
the doors which must be opened to make routine maintenance adjustments to
the system and to service the power supplies shall be push/pull-set,
automatic reset type.
2.3.1
Enclosure Covers
Covers of pull and junction boxes provided to facilitate installation of
the system need not be provided with tamper switches if they contain no
splices or connections, but shall be protected by tack welding or brazing
the covers in place. Zinc labels shall be affixed to such boxes indicating
they contain no connections. These labels shall not indicate that the box
is part of the security system.
2.3.2
Conduit-Enclosure Connections
All conduit-enclosure connections shall be protected by tack welding or
brazing the conduit to the enclosure. Tack welding or brazing shall be
done in addition to standard conduit-enclosure connection methods as
SECTION 16751A
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