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 MIL-HDBK-1012/1
fault current interrupters are required for security lights in the Quiet Zone.
Safety ground leads associated with these circuits must not be connected to
local earth grounds at individual fixtures. Non-conducting supports are
recommended. If conducting supports are used, individual isolation
transformers are required at each fixture to isolate safety and local grounds.
(2) Electrical security devices, energized entirely from
remote direct current sources, may be used in Quiet Zone B provided they are
not grounded to local grounds within the quiet zone.
(3) Guy wires terminated in Quiet Zone B are required to have
at least one insulator in each individual wire.
(4) A three dimensional clearance of at least 25 feet must be
maintained between the sea cable and any current-carrying conductors installed
in Quiet Zone B. Conductors crossing the cable path must be routed at right
angles to the cable for at least 25 feet on each side. Conductor paths
parallel to the cable shall be avoided. Any such conductors are required to
have two adjacent return conductors in the same cable arranged so as to cancel
magnetic fields. Overhead installations are preferable to buried
installations anywhere in the quiet zone.
(5) Security fences within Quiet Zone B are required to be
grounded and bonded as specified in para. 5.5.3.3. Fences crossing the cable
path must run at right angles to the cable for a distance of at least 25 feet
on each side of the cable. Care shall be exercised in placing fence posts on
any similar structures requiring excavation in quiet zones A or B.
8.12.3.3 Grounding. Special grounding plans, tailored to each site, are
required for oceanographic facilities and will be included in the BESEP where
appropriate. Complete isolation of signal, safety, and neutral grounds is
required except at specifically designated points.
a) All sites have main ground identified as the G2 ground. In
addition, some sites have special grounds (G1 and G3) which are directly
associated with underwater cables and are installed and maintained by
underwater cable installation organizations. G2 grounds normally consist of
multiple driven electrodes with a measured resistance of less than one ohm.
G2 ground field construction details are included in the BESEP where
appropriate.
b) The G2 ground field is connected to a main G2 ground plate by a
single, large (typically 750,000 circular mils) conductor. No other
connections to this ground field are authorized without specific written
permission from SPAWAR (PMW 180).
c) The main G2 ground plate is connected to a number of branch
ground plates dedicated to individual subsystems. One branch ground plate is
dedicated to safety grounds, building frame grounds, and power circuit neutral
ground connections. Other branches are connected to specific subsystems as
specified in the BESEP. These grounding systems are in accordance with Volume
2, para. 1.4.3 of MIL-HDBK-419 and NFPA 70, Article 250.
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