MIL-DTL-917 Electric Power Equipment, Basic Requirements ForThis specification covers the basic requirements applicable to the design, materials, and construction of naval shipboard electric power equipment \(exclusive of communication equipment, information technology \(IT\) equipment, and combat systems [fire control and weapons control equipment]\). Unless otherwise specified herein, the electric equipment developed for shipboard use under the requirements of this specification are limited to a maximum 450 volt \(V\) alternating current \(AC\) and a maximum 1,000 V direct current \(DC\). This equipment is intended for use on surface and submarine naval vessels \(see 6.2\).

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MIL-DTL-917F(SH)

PARAGRAPH

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3.2.21 Leakage current ....................................................................................................................................... 21

3.2.22 Electrical creepage and clearance distances............................................................................................. 22

3.2.22.1 Distance from enclosure ................................................................................................................... 22

3.2.23 Piping systems ......................................................................................................................................... 23

3.2.24 Screw thread standards for fastening devices .......................................................................................... 23

3.2.24.1 Fastening of parts.............................................................................................................................. 24

3.2.24.2 Fitted bolts ........................................................................................................................................ 24

3.2.24.3 Threads in aluminum ........................................................................................................................ 24

3.2.24.4 Threads in plastic .............................................................................................................................. 24

3.2.24.5 Inserts ............................................................................................................................................... 24

3.2.24.6 Thread projection.............................................................................................................................. 24

3.2.24.7 Bolt and screw thread engagement ................................................................................................... 24

3.2.24.8 Thread locking of mechanical assemblies ........................................................................................ 25

3.2.24.9 Fastening devices .............................................................................................................................. 25

3.2.24.9.1 Nuts, bolts, and screws .............................................................................................................. 25

3.2.24.9.2 Self-locking screws and bolts .................................................................................................... 25

3.2.24.9.3 Flat-head screws ........................................................................................................................ 25

3.2.24.9.4 Blind fasteners ........................................................................................................................... 25

3.2.24.9.5 Plastic ring and spring beam nuts .............................................................................................. 25

3.2.24.10 Thread-cutting screws ..................................................................................................................... 25

3.2.24.11 Washers .......................................................................................................................................... 25

3.2.24.11.1 Lockwashers ............................................................................................................................ 26

3.2.24.11.2 Flat washers ............................................................................................................................. 26

3.2.24.12 Lockwire and safety cable .............................................................................................................. 26

3.2.24.13 Liquid locking adhesives ................................................................................................................ 26

3.2.24.14 Prohibited locking devices .............................................................................................................. 26

3.2.25 Utilization of standard tools..................................................................................................................... 27

3.2.26 Equipment insulation requirements ......................................................................................................... 27

3.2.26.1 Required test ..................................................................................................................................... 27

3.2.27 Special shipboard environmental conditions ........................................................................................... 27

3.2.27.1 Wind speed ....................................................................................................................................... 27

3.2.27.2 Ice ..................................................................................................................................................... 27

3.3 Materials ........................................................................................................................................................... 27

3.3.1 Prohibited materials ................................................................................................................................... 27

3.3.1.1 Toxic pyrolytic materials .................................................................................................................... 28

3.3.1.1.1 Pyrolysis test ................................................................................................................................ 28

3.3.1.2 Mercury .............................................................................................................................................. 28

3.3.1.3 Asbestos.............................................................................................................................................. 28

3.3.1.4 Silicone ............................................................................................................................................... 28

3.3.1.5 PCBs ................................................................................................................................................... 28

3.3.1.6 PVC .................................................................................................................................................... 28

3.3.1.7 Cadmium and cadmium plating .......................................................................................................... 28

3.3.1.8 Other prohibited materials .................................................................................................................. 29

3.3.1.9 Flammable materials........................................................................................................................... 29

3.3.1.10 Fragile or brittle materials................................................................................................................. 30

3.3.2 Metals ........................................................................................................................................................ 30

3.3.2.1 Selection of metals in direct contact ................................................................................................... 30

3.3.2.2 Malleable iron and nodular graphitic iron castings............................................................................. 30

3.3.2.3 Corrosion-resistant metals .................................................................................................................. 30

3.3.3 Plastics ....................................................................................................................................................... 31

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