3.8
GROUNDING
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NOTE: If not specified in Division 16,
"Electrical," the following sentence shall be added:
"Wires inside the enclosure and for a distance of at
least 15 meters 50 feet outside of the enclosure
shall be enclosed in a grounded, threaded rigid
steel conduit system."
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Extend the grounding stud through and [bolt] [weld] it to the electrical
power panel with a minimum No. 4 AWG insulated stranded copper conductor to
effectively serve as a single grounding point for the completely assembled
shielded enclosure, both internally and externally.
3.9
SERVICE ENTRANCE PLATE
Install RF connectors for coaxial cable and other RF shielded cable on
entrance plate. Soft solder connectors to the plate. If location of plate
is not indicated, mount plate in wall panel adjacent to power line filters.
3.10
FIELD TESTS
3.10.1
Seam Leak Detection Testing
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NOTE: SELDS testing the seams in the floor
shielding is usually very difficult because you
cannot "sniff" on both sides (assuming the shield is
on the ground level). To circumvent this problem
SELDS loops may be positioned beneath the floor
shield for SELDS testing.
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Continuously test seams during fabrication using the SELDS, commonly known
as a "sniffer." Upon completion of the basic shielded enclosure, before
applying any metal primer or installing any accessories, test the entire
shielded enclosure with the SELDS. Install terminal points on the
shielding exterior and permanently attach test leads on two sets of
diagonally opposing corners during construction for use with the SELDS.
Continuously probe seams with the test receiver set to detect abrupt change
of shielding level greater than 10 dB on the "shielding unit" scale.
Clearly mark points having change greater than 10 dB and repair the seam to
meet the specified requirement. Retest each repaired point until there are
no points on seams which fail test.
3.10.2
Attenuation Testing
[Furnish the services of an independent testing laboratory, approved by the
Contracting Officer, to test the shielded enclosure. Certify that
laboratory is equipped and staffed to perform field tests of RF shielded
enclosures and performs the tests as a normal service.] [Final acceptance
testing will be by the Government.] Conduct the final shielding acceptance
test after penetrations have been completed, specifically including
electrical and other utility penetrations. In addition, the Contractor may
schedule a complete or abbreviated test to verify that the shielding
assembly is adequate prior to conducting final shielding acceptance test.
SECTION 13093N
Page 17
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