1、 MIL-DTL-24646B 29 April 2008 SUPERSEDING MIL-DTL-24646A 26 February 2001 DETAIL SPECIFICATION FUSE BOXES, GENERAL SPECIFICATION FOR This specification is approved for use by all Departments and Agencies of the Department of Defense. 1. SCOPE 1.1 Scope. This specification covers the general requirem
2、ents for fuse boxes with or without switches used on Naval ships. 1.2 Part or Identifying Number (PIN). The PIN will consist of the following: M24646/1- 001 Designator and specification sheet number Dash number (see 3.1) 2. APPLICABLE DOCUMENTS 2.1 General. The documents listed in this section are s
3、pecified in sections 3, 4 or 5 of this specification. This section does not include documents cited in other sections of this specification or recommended for additional information or as examples. While every effort has been made to ensure the completeness of this list, document users are cautioned
4、 that they must meet all specified requirements of documents cited in sections 3, 4 or 5 of this specification, whether or not they are listed. 2.2 Government documents. 2.2.1 Specifications, standards, and handbooks. The following specifications, standards, and handbooks form a part of this documen
5、t to the extent specified herein. Unless otherwise specified, the issues of these documents are those cited in the solicitation or contract (see 6.2). FEDERAL SPECIFICATIONS QQ-B-654 - Brazing Alloys, Silver. QQ-N-281 - Nickel-Copper Alloy Bar, Rod, Plate, Sheet, Strip, Wire, Forgings, and Structura
6、l and Special Shaped Sections. Comments, suggestions, or questions on this document should be addressed to: Defense Supply Center, Columbus, ATTN: DSCC-VAT, Post Office Box 3990, Columbus, Ohio 43218-3990 or by email CircuitProtectdla.mil. Since contact information can change, you may want to verify
7、 the currency of this address information using the ASSIST Online database at http:/assist.daps.dla.mil. AMSC N/A FSC 5920 INCH-POUND Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-24646B 2 FEDERAL STANDARDS FED-STD-28 - Screw - Thread Stand
8、ards for Federal Services. FED-STD-28/2 - Screw - Thread Standards for Federal Services, Section 2, Unified Inch Screw Threads - UN and UNR Thread Forms. COMMERCIAL ITEM DESCRIPTIONS A-A-59142 - Rosins: Gum, Wood, and Tall Oil. DEPARTMENT OF DEFENSE SPECIFICATIONS MIL-S-901 - Shock Tests, H.I. (High
9、-Impact); Shipboard Machinery, Equipment, and Systems, Requirements for. MIL-E-917 - Electric Power Equipment, Basic Requirements. MIL-E-2036 - Enclosures for Electric and Electronic Equipment. MIL-DTL-15024 - Plates, Tags, and Bonds for Identification of Equipment, General Specification for. MIL-P-
10、15024/5 - Plates, Identification. MIL-PRF-15160 - Fuses: Instrument, Power, and Telephone, General Specification for. MIL-DTL-15291 - Switches, Rotary, Snap Action and Detent/Spring Return Action, General Specification for. MIL-I-24768/1 - Insulation, Plastic, Laminated Thermosetting, Glass-Cloth Me
11、lamine-Resin (GME). DEPARTMENT OF DEFENSE STANDARDS MIL-STD-108 - Definitions of and Basic Requirements for Enclosures for Electric and Electronic Equipment. MIL-STD-167-1 - Mechanical Vibrations of Shipboard Equipment (Type I - Environmental and Type II - Internally Excited.) MIL-STD-202 - Test Met
12、hod Standard Electronic and Electrical Components Parts. (Copies of these documents are available online at http:/assist.daps.dla.mil/quicksearch/ or http:/assist.daps.dla.mil or from the Standardization Document Order Desk, 700 Robbins Avenue, Building 4D, Philadelphia, PA 19111-5094). 2.2.2 Other
13、Government documents, drawings, and publications. The following other Government documents, drawings, and publications form a part of this document to the extent specified herein. Unless otherwise specified, the issues are those cited in the solicitation or contract). NAVAL SEA SYSTEMS COMMAND (Ship
14、 Systems) NAVSHIPS 9000-S6202-73055 - Fabricated Terminals (Closed End) and Branch Buses for Electrical Fittings. NAVSHIPS 9000-S6202-73246 - Fabricated Terminals (Closed End) and Main Buses for Electrical Fittings. (Copies of these documents are available from http:/www.navsea.navy.mil, or the Comm
15、ander Naval Sea Systems Command, SEA 05M2, 1333 Isaac Hull Avenue SE Stop 5160, Washington Navy Yard DC 20376-5160). 2.3 Non-Government publications. The following documents form a part of this document to the extent specified herein. Unless otherwise specified, the issues of these documents are tho
16、se cited in the solicitation or contract. (see 6.2). Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-24646B 3 AMERICAN SOCIETY OF MECHANICAL ENGINEERS (AMSE) ASME B46.1 - Surface Texture (Surface Roughness, Waviness, and Lay). (Copies of thes
17、e documents may be obtained from http:/www.asme.org/ or ASME International, Three Park Avenue, New York, NY 10016-5990, 800-843-2763 (U.S/Canada), 001-800-843-2763 (Mexico), 973-882-1170 (outside North America), Email: infocentralasme.org). AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM) ASTM A342
18、/A342M - Standard Test Methods for Permeability of Feebly Magnetic Materials. ASTM B16/B16M - Rod, Brass, Free-Cutting, Bar and Shapes for use in Screw Machines. ASTM B36/B36M - Plate, Brass, Sheet, Strip and Rolled Bar. ASTM B584 - Castings, Copper Alloy Sand, for General Applications. ASTM B633 -
19、Electrodeposited Coating of Zinc on Iron and Steel, Standard Specification for. ASTM D4066 - Nylon Injection and Extrusion Materials (PA). (Copies of this document are available from http:/www.astm.org or the American Society for Testing Materials, 100 Barr Harbor Drive, West Conshohocken. PA 19428-
20、2959). 2.4 Order of precedence. In the event of a conflict between the text of this document and the references cited herein (except for related specification sheets), the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a s
21、pecific exemption has been obtained. 3. REQUIREMENTS 3.1 Specification sheets. The individual item requirements shall be as specified herein and in accordance with the applicable specification sheet. In the event of any conflict between requirements of this specification and the specification sheet,
22、 the latter shall govern. 3.2 First article. When specified, a sample shall be subjected to first article inspection (see 4.3 and 6.3). 3.3 Materials. Materials shall be as specified (see 3.1). When not specified, the contractor may select any material that will perform the intended function in the
23、equipment and will otherwise comply with the requirements of this specification. 3.3.1 Metals. Metals shall be of a corrosion-resistant type or shall be treated to resist corrosion as specified in MIL-E-917. Dissimilar metals, in contact with each other, shall be selected as specified in MIL-E-917.
24、The selection of metals in contact shall also be such as to prevent galling. 3.3.1.1 Nonmagnetic materials. When specified (see 3.1), all parts for nonmagnetic fuse boxes shall be of a nonferrous material or a material generally considered nonmagnetic. The magnetic permeability shall be not greater
25、than 2.0 after fabrication (see 4.6.10). 3.3.2 Brazing alloys. Brazing alloys for electrical connections shall be silver alloy type as specified in class BAg of QQ-B-654. 3.3.3 Nonmetallic materials. Nonmetallic materials shall be nonflammable, nontoxic, and fungus-inert as specified in MIL-E-917. 3
26、.3.3.1 Polyamide (nylon)parts. Molded polyamide (nylon) parts shall be in accordance with ASTM D4066 Group 1, Class 8, Grade 1. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-24646B 4 3.3.4 Prohibited materials. Prohibited materials shall be
27、 as specified in MIL-E-917 with the following additions: a. Asbestos. b. Cadmium. c. Mercury (see 3.3.4.1). 3.3.4.1 Mercury. In addition to the mercury requirement as specified in MIL-E-917, no parts shall have come in direct contact with metallic mercury, mercury compounds, or mercury bearing instr
28、uments or devices, employing only a single boundary of containment, during manufacture or inspection. (A single boundary of containment is one which is not backed up by a second seal or barrier to prevent escape and consequent mercury contamination in the event of rupture of the primary seal or barr
29、ier.) 3.3.5 Recycled, recovered, or environmentally preferable materials. Recycled, recovered, or environmentally preferable materials should be used to the maximum extent possible provided that the material meets or exceeds the operational and maintenance requirements, and promotes economically adv
30、antageous life cycle costs. 3.4 Parts. 3.4.1 Fuse clips. Fuse clips shall be as specified (see 3.1). Fuse clip retainers shall not be used with fuse clips for fuses rated 0-60 amperes (A). The clip shall be secured to the branch bus to allow easy removal without requiring disassembly of other parts
31、and will withstand a pull-force as specified in 4.6.1. 3.4.2 Fuse base. The fuse base shall be of glass melamine, as specified in type GME of MIL-I-24768/1, or shall be a material selected from the laminates as specified in MIL-E-917, provided they meet the electrical and mechanical requirements (se
32、e 3.1). The laminate shall be furnished in natural color except polyester laminates may be furnished in tan or red. Current carrying parts (less switches) shall be mounted on the fuse base. Unless otherwise specified (see 3.1), the fuse base shall be mounted in the approximate center of the enclosur
33、e. 3.4.3 Bus bars and connections. Bus bars and connections shall be brass, as specified in ASTM B16/B16M, ASTM B36/36M, and ASTM B584. 3.4.3.1 Main bus bars. Main bus bars shall be of the sizes as specified (see 3.1). Holes in the bus bars may be punched or drilled and the contact area shall be smo
34、oth. Where punching is used, the operation shall not appreciably indent the surface of the bus bar in the vicinity of the hole. 3.4.3.2 Branch bus bars. Unless otherwise specified, branch bus bars shall be of the sizes as specified in Drawing 9000-S6202-73055 and shall be selected for the applicatio
35、n specified (see 3.1). 3.4.3.3 Main and branch terminals. Unless otherwise specified (see 3.1), main and branch terminals shall be as specified in Drawings 9000-S6202-73055 and 9000-S6202-73246 and shall be selected for the applicable wire size specified (see 3.1). Terminals shall be silver brazed t
36、o the bus bars. 3.4.3.4 Studs and stud type main cable terminals. Unless otherwise specified (see 3.1), studs and stud type main cable terminals shall be as specified in Drawing 9000-S6202-73055 and shall be through bolted at the main bus bar. The nuts shall be torqued to 6.5 .5 foot-pounds and tack
37、 welded by gas tungsten arc welding as specified in commercial procedures using CU-SN-C wire with 0.035 inch diameter. Only two tack welds shall be applied, one opposite the other at the junction of the nut flats and the main bus. One tack weld shall be applied to all nuts before the second tack wel
38、d is applied. All nuts shall be of brass. Self locking brass nuts may be used in lieu of nuts requiring tack welding at the option of the contractor. The stud or main cable terminal may be ground smooth at the nut to meet electrical clearance requirements. Stud connections to the branch buses shall
39、be as specified in Drawing 9000-S6202-73055. Stud connections shall be silver brazed to the branch and feeder bus bars. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-24646B 5 3.4.3.5 Switch terminal connector. The terminal connector between
40、 the branch bus and switch shall be sized and formed as shown (see 3.1). 3.4.4 Switches. Where required (see 3.1), switches shall be as specified in MIL-DTL-15291. Switch type shall be as specified (see 3.1). 3.4.4.1 Handles. Switch handles shall be brass, as specified in ASTM B584, or molded polyam
41、ide (nylon) and shall be as shown on figure 1. Handles shall be secured to the shaft extension by the use of corrosion resistant steel (CRES) setscrews, commercial grade. 3.4.4.2 Shaft extensions and coupling plates. Switch shaft extensions and coupling plates shall be zinc plated steel, CRES commer
42、cial grade, or nickel copper alloy as specified in QQ-N-281. For submersible fuse panels, the shaft shall be CRES or nickel-copper alloy per QQ-N-281. Cups shall be brass and coupling plates shall be brass or CRES. Molded polyamide (nylon) may be used for shaft extensions, cups and coupling plates a
43、t the option of the contractor. The shaft extension shall, regardless of manufacturer, mate with and be compatible with the switch handle shown on figure 1. The coupling plates may be as shown on figure 1 or may be contractors choice, providing they meet the requirements specified herein. Pins shall
44、 be of austenitic CRES commercial grade, or nickel-copper alloy as specified in QQ-N-281. 3.4.5 Commercial (hardware) parts. Commercial utility hardware items such as screws, bolts, and nuts may be used, provided they possess properties equivalent to and are replaceable by MS or AN part numbers. 3.4
45、.6 Mounting parts. Unless otherwise specified (see 3.1), mounting parts, such as brackets, straps, angles, and pads shall be of the same material as the enclosure. 3.5. Design and construction. Fuse boxes shall be of the design, construction, and physical dimensions as specified (see 3.1). Fuses and
46、 wiring shall not be furnished. 3.5.1 Enclosures. Enclosures shall be of the material specified and shall be submersible (15-foot), watertight, or totally enclosed as specified (see 3.1). 3.5.1.1 Wiring diagram. The wiring diagram (see 3.1), shall be as specified in MIL-E-2036 except the plastic pro
47、tective material shall be a clear plastic laminating film, 10-mils minimum thickness, of polycarbonate, polyester (PET), polypropylene, or other suitable commercial grade plastic, which is tough, rigid and chemically resistant. 3.5.1.2 Cable entrance. Unless otherwise specified (see 6.2), holes for
48、stuffing tubes or cable connectors shall not be provided. 3.5.1.3 Stuffing tubes. Unless otherwise specified (see 6.2), stuffing tubes shall not be furnished. 3.5.1.4 Mounting. The location of mounting holes shall be as specified (see 3.1). The enclosure shall support the total assembly of the box,
49、fuses, switches, where required, and associated hardware by the mounting means specified. Mounting bolts shall not be furnished. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-24646B 6 FIGURE 1. Switch handle and shaft linkage. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-24646B 7 3.5.2
