MIL-DTL-16036M(SH)
3.10.13 Bus bar capacity. Main bus bar rating shall be not less than the largest feeder circuit element rating of
the power source supplying the main bus. If the bus is fed via a transformer, bus bar rating shall not be less than the
transformer secondary current. Units shall accept the maximum bus size required for standardized units as shown on
figure 9. Either main bus taps or branch bus taps feeding three or more AQB circuit breakers shall be sized based on
75 percent of the sum of the active and spare circuit breaker frame sizes (maximum current rating) supplied, but not
exceeding the main bus rating. Main bus taps and branch bus taps feeding one or two circuit breakers shall be sized
based on 100 percent of the active and spare circuit breaker frame sizes supplied, but not exceeding the main bus
rating.
3.10.14 Bus bar insulation. When specified (see 6.2), bus bars within the switchboard shall be insulated with
MIL-E-22118 materials or other approved electrical insulating materials or compounds to improve creepage
distances. When insulating varnish is utilized the coating shall be flexible, tough, moisture and acid resisting, and
shall have an insulation resistance value of at least 500 volts per mil of thickness. One coat, 0.004 to 0.006 inch
thick, shall be applied. Before painting, burrs and sharp edges shall be removed and bus bars cleaned to remove
dust, grease, oil, or other foreign material. Paint may be applied by spraying or flowed on with a soft bristle brush
when spraying is impractical. Coatings shall be free from pinholes. Bus bars shall be painted before assembly up to
1/4 to 1/2 inch from joint area. All current-carrying parts, including bus joints and connections, shall be insulated
upon completion of final shipboard assembly. A hard copy of installation instructions shall be provided by the
switchboard manufacturer and installation instructions shall include a list of joints that are required to be insulated
during installation as well as procedures for insulating the listed joints.
3.10.15 Cable lug terminals. Cable lug terminals installed on all cables entering or within the switchboard shall
be crimp Type CLC or CLCG in accordance with MIL-T-16366 or ring tongue SAE-AS7928, Type I, Class 1 or
cable lug terminals approved by the installing activity as specified (see 6.2). Prior to assembly and crimping, a light
coating of corrosion preventive paste in accordance with MIL-C-11796 shall be applied to the conductor and the
interior of the terminal lug barrel. CLC or CLCG lug terminals shall be used with ACB circuit breakers or bus bar
applications. Cable lug terminals shall not be installed on spare circuit breakers to which a cable is not attached.
For all cables, cable lug terminals shall be secured by means of locking devices in accordance with 3.5.12.3. A
tightening sequence (torque and location) as described in Section 4 of S9086-CJ-STM-010, NSTM Chapter 075
shall be used when multiple bolts are present. Cable lug terminals for cables entering a switchboard may be
furnished by the installing activity when specified (see 6.2).
3.10.16 Connections between buses. Connections between the buses of adjacent sections of a switchgear group
may be made by cables instead of solid bus bars to permit relative movement of the sections under shock without
rupturing the switchboard main bus circuit. A means for readily disconnecting the cables from the bus shall be
provided in all sections having a source of power other than from the connecting cables. The disconnecting device
shall have a rating equal to the main bus. Cable connections shall be made by the installing activity. Switchboard
arrangement shall include means to provide for the entrance of the connecting cable into the switchboard structure
and for connecting the cables to the switchboard bus. Connecting cables shall have a current rating equal to that of
the smaller of the two connected buses. Consideration shall be given to facilitate connection (by the installing
activity) for the ship s cable to the switchboard so that these cables will not result in restriction of access features.
Armor shall be removed from the portion of ship s cables inside the switchboard. Instructions for interconnecting
wiring shall be shown on the switchboard drawings.
3.10.17 Cables entering switchboards. Cables shall enter the switchboard from either the top or bottom.
Cables entering through the top dripshield shall not compromise the watertight integrity of the dripshield.
Switchboard arrangement as specified (see 6.2) shall provide for proper cable connections without restrictions of
access features.
3.10.18 Special requirements for 100-ampere frame circuit breaker base connections.
3.10.18.1 Insulation distances. Bus to component stud line-side and load-side connections on 100-ampere
frame circuit breaker bases shall meet the following requirements:
a. Bus connections within 4 inches of the bus/component stud connection shall meet the clearance distances of
MIL-E-917.
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