MIL-DTL-917F(SH)
3.12.3.3 Standard marking for connections. Identification marking shall be in accordance with MIL-STD-681
for those items of equipment listed therein. Other items, the marking of which is not covered by MIL-STD-681 or
by other applicable standards or specifications, shall have identifying terminal marking using numbers or letters or a
combination of both. Wiring documentation shall be in accordance with ASME Y14.100, ASME Y14.24, and
ASME Y14.34, as specified (see 6.2).
3.12.4 Bus bars. Design of bus bars including materials, sizes, spacing, arrangements, and joints shall be in
accordance with MIL-DTL-16036. All connections to bus bars shall be made by throughbolting the bus bar. Link
or tap changing connectors are not to be considered bus bars. When specified (see 6.2), bus bars shall be insulated
with materials in accordance with MIL-E-22118 for surface ships and MIL-I-15265 for submarine applications. All
joints, except those required for final shipboard installation, shall be insulated after assembly. Insulation distances
(clearance in air and surface creepage) of bus bars with external cabling and all associated hardware (lugs, bolts,
nuts, washers, and so forth) installed shall conform to the requirements of MIL-DTL-16036. Installation
instructions shall include a list of joints requiring insulation such that all current carrying parts will be insulated
upon completion of final shipboard installation. For laminated bus bars, the above requirements do not apply
provided that laminated bus bars shall be encapsulated and all exposed hook-up current carrying copper surfaces
shall be silver coated to control corrosion.
3.12.5 Fiber optic connections.
3.12.5.1 Fiber optic cables. Fiber optic cables shall comply with the requirements of MIL-PRF-85045.
3.12.5.2 Fiber optic connectors. Fiber optic connectors shall comply with the requirements of
MIL-DTL-83522.
3.13 Parts. Only parts specified herein shall be incorporated into the design of the equipment.
3.13.1 Parts selection. Parts not specified herein shall be selected from the applicable individual equipment
specification.
3.13.1.1 Parts derating. Derating of electronic parts shall be in accordance with the requirements of this
specification while observing the additional guidance of MIL-HDBK-338.
3.13.1.1.1 Resistor and rheostat derating. Power dissipation in resistors and rheostats shall not exceed
50 percent of the rated value after applicable derating and ambient temperature factors have been applied in
accordance with the part specification.
3.13.1.1.2 Capacitor derating. Capacitors shall be derated at least 50 percent. The expected peak voltage of a
capacitor under nominal and steady state tolerance conditions of AC voltage and frequency input and signal levels
with the equipment operating in the maximum ambient design temperatures shall not exceed ½ times the capacitor
maximum voltage rating. Use of a derating factor for capacitors different than 50 percent shall be approved by
NAVSEA.
Under transient or over-voltage conditions, no capacitor maximum voltage rating shall be exceeded. A derating
factor lower than 50 percent should not be used due to the space required for larger capacitors. The root mean
square (rms) value of any capacitor current due to an AC applied voltage or an AC ripple voltage superimposed on a
DC basis shall not exceed 50 percent of rated value for the capacitor.
3.13.1.1.3 Discrete semiconductor derating and application stresses. Semiconductor devices rated 5 amperes
and less are based on the absolute system (see the definitions in the appendix of MIL-PRF-19500). Power diodes
and silicon-controlled rectifiers (SCRs) above 5 amperes shall follow the format as described in table XIX. These
ratings shall not be exceeded under any service or test. Further, no two of the rated values (for example, voltage and
current) shall be imposed at the same time. Semiconductor devices shall be chosen and applied in such a way that
the worst stress of each type imposed on the device with any available setting of adjustable circuit parts does not
exceed its rated value for that stress factor as specified by the applicable device detail specification. This shall
include stresses under surge or transient conditions from clearing of grounds, shorts, or other faults on the power
system that may result from operation of protective devices.
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