1、FORD MANUFACTURING STANDARDS EWl JUNE 1993 POWER DISTRIBUTION FROM BUS DUCT SYSTEMS EWl Page 1 1. 1.1 1.2 1.3 2. 2.1 2.2 GENERAL: SCOPE: This standard describes the installation of bus drop cable, supports required, and devices and methods of terminating the cable. (See illustration on page 5). It a
2、lso describes conduit installations where the use of bus drop cable is not practicable. Whenever a specific standard is mentioned in this Standard, it is understood it will be the latest revision thereof unless otherwise specified. SAFETY: Refer to Ford Industrial Relations Safety Technical Bulletin
3、 No. 133 - “Safety Guidelines for the Installation of Electrical Distri- bution Busway Plug-in Units on Energized Busways“ for procedures to follow when installing or removing Busplugs. REFERENCE STANDARDS: ANSI/NFPA 70, “National Electric Code“. ASTM B-8, “Specification for Concentric-Lay Stranded
4、Copper Conductors, Hard, Medium-Hard or Soft“. ASTM B-174, “Specification for Bunch-Stranded Copper Conductors for Electrical Conductors“. ICEA S-61-402/NEMA WC 5, “Thermoplastic-insulated Wire and Cable for the Transmission and Distribution of Electrical Energy“. Ford Manufacturing Standards EEl, E
5、E2, EE4, and EXl Canadian Standards Association (CSA) C22.10, “Canadian Electric Code Part I (16th Ed.) plus Quebec Amendment“. BUS DROP CABLE: SIZE: The size of the cable shall suit the power requirements of the industrial equipment served. In no case shall it be smaller than size AWG (American Wir
6、e Gage) 12, or larger than size AWG 2. The cable shall include three power conductors and a grounding wire or wires. Section 6.0 describes installations requiring sizes larger than AWG 2. CONDUCTORS: Each conductor shall have at least seven strands of soft drawn. annealed Conner ner ASTM B-8 Class C
7、 or B-174 Class K- m =ill!J=iLbD 0051bi3 373 - FORD MANUFACTURING STANDARDS EWl JUNE 1993 POWER DISTEIBUTION FEOM BUS DUCT SYSTEMS Page 2 2.3 INSULATION: The cable shall be rated 600 VAC, minus 20 to +75 deg.C, be Underwriters Laboratories, Inc. (UL) Listed, and conform to ICEA and National Electric
8、al Code requirements. Individual thermoplastic insulated conductors shall be colored black, white, and red. The grounding wire or wires need not be insulated or if insulated they shall be green. The thermoplastic cable jacket shall be oil, water, ozone, corrosives and abrasion resistant. 3. TERMINAT
9、IONS: 3.1 All cable grips used under this standard shall be UL Listed and/ or CSA certified as required at the location where the equipment is to be installed. Holes in enclosures shall be ma& only with manually or hydraulically operated punches and dies, except for knockouts furnished in some types
10、 of bus plugs. Ground wires in the bus drop cable shall be twisted together and properly bonded to the enclosure at each termination with ring type crimp terminals or to lugs provided for this purpose. Plastic insulated bushings shall be installed on the threaded end of the grip connectors inside al
11、l enclosures, and are typically furnished with the connector. 3.2 TERMINATIONS AT THE BUS PLUG: Where the cable terminates at the bus plug, it shall pass through a wide-range strain relief grip having a neoprene gasket or seal around the cable to exclude dust. The connector portion of the grip shall
12、 have an attached single/double weave, stainless steel mesh extending at least five inches along the cable to prevent its pull out at the terminals inside the bus plug, control its bend radius and relive strain, in accordance with National Electrical Code sections 364-8 and 400-10. The grip shall be
13、 sized to avoid any stripping of the cable jacket where it passes through the connector body. 3.3 TERMINATIONS AT THE CONTROL ENCLOSURE (over 6 feet): Where the top of the control enclosure is six feet or more above the floor, the bus drop cable shall enter the enclosure through a deluxe cord grip,
14、which has the same mesh as the strain relief grip, but adds a neoprene grommet and compression nut to exclude both dust and liquids. A wide-range strain relief grip may be used, if permitted in writing by the specifying activity. FORD MANUFACTURING STANDARDS Ewl JUNE 1993 POWER DISTRIBUTION FROM BUS
15、 DUCT SYSTEMS EWl Page 3 3.4 TERMINATIONS AT THE CONTROL ENCLOSURE (under 6 feet): Where the top of the control enclosure is less than six feet from the floor, the bus drop cable shall be protected by a conduit riser to a height of eight feet above the floor. The strain relief grip and connector sha
16、ll then be attached to the upper end of the conduit. The conduit riser shall be rigidly supported with angle or channel iron braces. The conduit and supports shall be attached to the electrical control enclosure so that the control enclosure and conduit riser can be moved as one unit. 3.5 TERMINATIO
17、NS AT NEMA 12 DISCONNECT SWITCHES: Where the main discon- necting means for a piece of industrial equipment consists of a NEMA 12 disconnect switch or combination starter, such as may be found on a conveyor or drill press for example, the same methods of termination given above in Sections 3.3 or 3.
18、4 shall apply, depending on the height of the top of disconnect enclosure. The angle or channel iron bracing shall be attached to a structural member of the equipment. 4. CABLE STORAGE LOOPS: 4.1 At least one loop of cable shall be provided to allow for minor changes in equipment location. The speci
19、fying activity shall specify the diameter and number of loops. The loop or loops shall be supported by a quarter-bend cable clamp to hold the bus drop cable firm, and to which a guy cable spring can be attached. 4.2 The cable storage loop may be located above the bus plug or at the point where the h
20、orizontal run of cable drops down to the electrical control enclosure, as outlined in the requisitioners specifications. 5. CABLE SUPPORTS AND ACCESSORIES: 5.1 SAG LIMITATION: The horizontal run of bus drop cable shall be adequately supported. The sag shall not exceed six inches per twenty-five feet
21、 of cable. 5.2 GUY CABLES: The guy cable shall be extra flexible aircraft cable 7x19x1/8 inch diameter. Wire rope clamps shall be used at each termination of the guy cable. 5.3 SPRINGS: A spring shall be inserted between the guy cable and quarter-bend clamps. The spring pressure shall limit sag of t
22、he horizontal section of the bus drop cable to levels described in 5.1. FORD MANUFACTURING STANDARDS EWl JUNE 1993 POWER DISTRIBUTION FROM BUS DUCT SYSTEMS EWl Page 4 5.4 ANCHORING GUY CABLES: The guy cable shall be fastened to the structural steel of the building with a beam clamp. No holes shall b
23、e drilled in the structural steel for anchoring guy cables nor shall any brackets or hangers be permanently welded in place. Messenger cable may be installed if necessary and used to anchor guy cables. 6. CONDUIT INSTALLATIONS: 6.1 CRANE BAY AREAS: In areas where overhead cranes are used, bus drop c
24、able shall not be installed. All service wiring shall be in rigid steel conduit and installed as describes in either 6.3 or 6.4. No conductor shall be smaller than AWG 12 and no conduit shall be smaller than 3/4 inch. 6.2 CABLE LARGER THAN AWG 2: Installations requiring conductors larger than size A
25、WG 2 shall be connected to the bus duct system through bus plugs and individual conductors installed in conduit. 6.3 OVERHEAD CONDUITS: When conduit is installed overhead, it shall be supported from elements of the building structural steel and furnished with boxes and pulling fittings as may be req
26、uired in accordance with National Electrical Code article 300, 346, and 370 and any local code requirements. Where practical, conduit that follows the bottom chord of the building truss shall be installed above the chord so the conduit with its beam clamps and other supports will not be subject to d
27、amage from vehicles or any objects passing closely under the truss. Similarly, vertical runs of con&it along building columns and their attached boxes and fittings shall be located inside the column web to avoid exposure to damage. Runs of conduit shall be kept at least 12 inches away from other pip
28、es or surface carrying hot or cold media such as steam pipes, chill water pipes, ovens, washers, etc. 6.4 6.5 CONDUITS IN THE FLOOR: Conduit installed in wood block floors shall run from the bus plug to the closest building column and down the column to the floor. The wood block floor shall be remov
29、ed in a neat, narrow trench. Concrete shall be chipped to a depth which will allow conduit and fittings to be at least one inch below the top surface of the wood block. After the conduit is installed, the remaining trench space shall be filled with a coarse grade, mastic floor patching material as s
30、pecified by the requisitioning activity. CONDUIT, BOXES AND FITTINGS: Conduit, Boxes and Fittings shall conform to and be installed in accordance with the Ford Manufactu- ring Electrical Stan&rds listed above under Item 1.3. Installa- tions shall conform with this standard and with Section 13 of Standard EXl. FORD MANUFACTURING STANDARDS EWl JUNE 1993 POWER DISTRIBUTION FROM BUS DUCT SYSTEMS EWl Page 5 I- O 3 17 I CIY c
