Source: https://www.ecfr.gov/cgi-bin/text-idx?mc=true&node=se7.11.1755_1200&rgn=div8
Timestamp: 2020-02-16 20:38:23
Document Index: 578086592

Matched Legal Cases: ['art 1755', '§1755', '§1755', 'art 51', 'art 51', '§1755', '§1755']

Title 7 → Subtitle B → Chapter XVII → Part 1755 → §1755.200
§1755.200 RUS standard for splicing copper and fiber optic cables.
(a) Scope. (1) This section describes approved methods for splicing plastic insulated copper and fiber optic cables. Typical applications of these methods include aerial, buried, and underground splices.
(2) American National Standard Institute/National Fire Protection Association (ANSI/NFPA) 70, 1993 National Electrical Code (NEC) referenced in this section is incorporated by reference by RUS. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. A copy of the ANSI/NFPA 1993 NEC standard is available for inspection during normal business hours at RUS, room 2845, U.S. Department of Agriculture, Washington, DC 20250-1500, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal__register/code__of__federal__regulations/ibr__locations.html. Copies are available from NFPA, Batterymarch Park, Quincy, Massachusetts 02269, telephone number 1 (800) 344-3555.
(3) American National Standard Institute/Institute of Electrical and Electronics Engineers, Inc. (ANSI/IEEE), 1993 National Electrical Safety Code (NESC) referenced in this section is incorporated by reference by RUS. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. A copy of the ANSI/IEEE 1993 NESC standard is available for inspection during normal business hours at RUS, room 2845, U.S. Department of Agriculture, Washington, DC 20250-1500, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal__register/code__of__federal__regulations/ibr__locations.html. Copies are available from IEEE Service Center, 455 Hoes Lane, Piscataway, New Jersey 08854, telephone number 1 (800) 678-4333.
(b) General. (1) Only Rural Utilities Service (RUS) accepted filled cable and splicing materials shall be used on outside plant projects financed by RUS.
(c) Splicing considerations for copper cables—(1) Preconstruction testing. It is desirable that each reel of cable be tested for grounds, opens, shorts, crosses, and shield continuity before the cable is installed. However, manufacturer supplied test results are acceptable. All cable pairs shall be free from electrical defects.
(2) Handling precautions. The cable manufacturer's instructions concerning pulling tension and bending radius shall be observed. Unless the cable manufacturer's recommendation is more stringent, the minimum bending radius shall be 10 times the cable diameter for copper cables and 20 times the cable diameter for fiber optic cables.
(3) Cable sheath removal. (i) The length of cable sheath to be removed shall be governed by the type of splicing hardware used. Follow the splice case manufacturer's recommendations. For pedestals or large pair count splice housings, consider removing enough cable sheath to allow the conductors to extend to the top of the pedestal and then to hang downward to approximately 15 centimeters (cm) (6 inches (in.)) above the baseplate.
(4) Shield bonding and grounding. For personnel safety, the shields of the cables to be spliced shall be bonded together and grounded before splicing activities are started. (See paragraphs (g)(2), and (g)(5)(i) through (g)(5)(iii) of this section for final bonding and grounding provisions.)
(5) Binder group identification. (i) Color coded plastic tie wraps shall be placed loosely around each binder group of cables before splicing operations are attempted. The tie wraps shall be installed as near the cable sheath as practicable and shall conform to the same color designations as the binder ribbons. Twisted wire pigtails shall not be used to identify binder groups due to potential transmission degradation.
Table 1—Cable Pair Identification Within Binder Groups
1 White Blue.
2 White Orange.
3 White Green.
4 White Brown.
5 White Slate.
6 Red Blue.
7 Red Orange.
8 Red Green.
9 Red Brown.
10 Red Slate.
11 Black Blue.
12 Black Orange.
13 Black Green.
14 Black Brown.
15 Black Slate.
16 Yellow Blue.
17 Yellow Orange.
18 Yellow Green.
19 Yellow Brown.
20 Yellow Slate.
21 Violet Blue.
22 Violet Orange.
23 Violet Green.
24 Violet Brown.
25 Violet Slate.
Table 2—Cable Binder Group Identification
1 White-Blue 1-25
2 White-Orange 26-50
3 White-Green 51-75
4 White-Brown 76-100
5 White-Slate 101-125
6 Red-Blue 126-150
7 Red-Orange 151-175
8 Red-Green 176-200
9 Red-Brown 201-225
10 Red-Slate 226-250
11 Black-Blue 251-275
12 Black-Orange 276-300
13 Black-Green 301-325
14 Black-Brown 326-350
15 Black-Slate 351-375
16 Yellow-Blue 376-400
17 Yellow-Orange 401-425
18 Yellow-Green 426-450
19 Yellow-Brown 451-475
20 Yellow-Slate 476-500
21 Violet-Blue 501-525
22 Violet-Orange 526-550
23 Violet-Green 551-575
24 Violet-Brown 576-600
Table 3—Super-Unit Binder Colors
1-600 White.
601-1200 Red.
1201-1800 Black.
1801-2400 Yellow.
2401-3000 Violet.
3001-3600 Blue.
3601-4200 Orange.
4201-4800 Green.
4801-5400 Brown.
5401-6000 Slate.
Table 4—Screened Cable Service Pair Identification
1 White Red.
2 White Black.
3 White Yellow.
4 White Violet.
6 Red Yellow.
7 Red Violet.
8 Black Yellow.
9 Black Violet.
(6) Cleaning conductors. It is not necessary to remove the filling compound from cable conductors before splicing. However, it is permissible to wipe individual conductors with clean paper towels or clean cloth rags. No cleaning chemicals, etc., shall be used. Caution shall be exercised to maintain individual cable pair and binder group identity. Binder group identity shall be maintained by using color coded plastic tie wraps. Individual pair identification shall be maintained by carefully twisting together the two conductors of each pair.
(7) Expanded plastic insulated conductor (PIC) precautions. Solid PIC and expanded (foam or foam skin) PIC are spliced in the same manner, using the same tools and materials and, in general, should be treated the same. However, the insulation on expanded PIC is much more fragile than solid PIC. Twisting or forming expanded PIC into extremely compact splice bundles and applying excessive amounts of tension when tightening tie wraps causes shiners and, thus shall be avoided.
(8) Splice connectors. (i) Only RUS accepted filled splice connectors shall be used on outside plant projects financed by RUS.
(9) Piecing out conductors. Conductors may be pieced-out to provide additional slack or to repair damaged conductors. However, the conductors shall be pieced-out with conductors having the same gauge and type and color of insulation. The conductors used for piecing-out shall be from cables having RUS acceptance.
(10) Splice organization. Spliced pair bundles shall be arranged in firm lay-ups with minimum conductor tension in accordance with the manufacturer's instructions.
(11) Binder tape. Perforated nonhygroscopic and nonwicking binder tape should be applied to splices housed in filled splice cases. The binder tape allows the flow of filling compound while holding the splice bundles near the center of the splice case to allow adequate coverage of filling compound.
(12) Cable tags. Cables shall be identified by a tag indicating the cable manufacturer's name, cable size, date of placement, and generic route information. Information susceptible to changes caused by future cable throws and rearrangements should not be included. Tags on load coil stubs shall include the serial number of the coil case, the manufacturer's name, and the inductance value.
(13) Screened cable. Screened PIC cable is spliced in the same manner as nonscreened PIC cable. However, special considerations are necessary due to differences in the cable design. The transmit and receive bundles of the cable shall be separated and one of the bundles shall be wrapped with shielding material in accordance with the cable manufacturer's recommendations. When acceptable to the cable manufacturer, it is permissible to use either the scrap screening tape removed from the cable during the sheath opening process provided the screening tape is edge coated or new pressure sensitive aluminum foil tape over polyethylene tape.
(14) Service wire connections. (i) Buried service wires may be spliced directly to cable conductors inside pedestals using the same techniques required for branch cables. Buried service wires may also be terminated on terminal blocks inside pedestals in areas where high service order activity or fixed count cable administration policies require terminal blocks. However, only RUS accepted terminal blocks equipped with grease or gel filled terminations to provide moisture and corrosion resistance shall be used.
(15) Copper cable testing. Copper cable testing shall be performed in accordance with RUS Bulletin 345-63, “RUS Standard for Acceptance Tests and Measurements of Telephone Plant,” PC-4, (Incorporated by reference at §1755.97).
(16) Cable acceptance. Installed cable shall be tested and pass the inventory and acceptance testing specified in the Telephone System Construction Contract (Labor and Materials), RUS Form 515. The tests and inspections shall be witnessed by the borrower's resident project representative. All conductors shall be free from grounds, shorts, crosses, splits, and opens.
(d) Splice arrangements for copper cables—(1) Service distribution closures. (i) Ready access closures permit cable splicing activities and the installation of filled terminal blocks for service wire connections in the same closure. Ready access designs shall allow service technicians direct access to the cable core as well as the terminal block.
(2) Aerial splices. Aerial splice cases accommodate straight splices, branch splices, load coils, and service distribution terminals. Aerial splicing arrangements having more than 4 cables spliced in the same splice case are not recommended. Stub cabling to a second splice case to avoid a congested splice is acceptable.
(3) Buried splices. (i) Direct buried splice cases accommodate straight splices, branch splices, and load coils. Direct buried splices shall be filled and shall be used only when above ground splicing in pedestals is not practicable.
(4) BD-type pedestals. (i) BD-type pedestals are housings primarily intended to house, organize, and protect cable terminations incorporating splice connectors, ground lugs, and load coils. Activities typically performed in pedestals are cable splicing, shield bonding and grounding, loading, and connection of subscriber service drops.
Table 5—Splice Capacities for BD-Type Pedestals
BD3, BD3A 100 Pair 50 Pair.
BD4, BD4A 200 Pair 100 Pair.
BD5, BD5A 600 Pair 300 Pair.
BD7 1200 Pair 600 Pair.
BD14, BD14A 100 Pair 50 Pair.
BD15, BD15A 400 Pair 200 Pair.
BD16, BD16A 600 Pair 300 Pair.
(5) Large pair count splice housings. Large pair count splice housings are recommended for areas not suitable for man- holes. The recommended capacities are shown in Table 6:
Table 6—Splice Capacities for Large Count Housings
BD 6000 6,000 Pair 3,000 Pair.
BD 8000 8,000 Pair 4,000 Pair.
BD 10000 10,000 Pair 5,000 Pair.
(6) Pedestal restricted access inserts. Restricted access inserts may be used to protect splices susceptible to unnecessary handling where subsequent work activities are required or expected to occur after splices have been completed. Restricted access inserts also provide moisture protection in areas susceptible to temporary flooding. A typical restricted access insert is shown in Figure 1:
(7) Serving Area Interface (SAI) Systems. SAI systems provide the cross-connect point between feeder and distribution cables. Connection of feeder to distribution pairs is accomplished by placing jumpers between connecting blocks. Only RUS accepted connecting blocks having grease or gel filled terminations to provide moisture and corrosion resistance shall be used.
(8) Buried cable splicing arrangements. Typical buried cable splicing arrangements are illustrated in Figures 2 through 5:
(9) Underground splices (manholes). Underground splice cases accommodate straight splices, branch splices, and load coils. Underground splices shall be filled.
(10) Central office tip cable splices. (i) Filled cable or filled splices are not recommended for use inside central offices, except in cable vault locations. Outside plant cable sheath and cable filling compound are susceptible to fire and will support combustion. Fire, smoke, and gases generated by these materials during burning are detrimental to telephone switching equipment.
(e) Splicing considerations for fiber optic cables—(1) Connection characteristics. Splicing efficiency between optical fibers is a function of light loss across the fiber junctions measured in decibels (dB). A loss of 0.2 dB in a splice corresponds to a light transmission efficiency of approximately 95.5 percent.
(2) Fiber core alignment. Fiber splicing techniques shall be conducted in such a manner that the cores of the fibers will be aligned as perfectly as possible to allow maximum light transmission from one fiber to the next. Without proper alignment, light will leave the fiber core and travel through the fiber cladding. Light outside the fiber core is not a usable light signal. Core misalignment is illustrated in Figure 6:
(3) Splice loss. (i) Splice loss can also be caused by fiber defects such as nonidentical core diameters, cores not in center of the fiber, and noncircular cores. Such defects are depicted in Figure 7:
(4) Handling precautions. The following precautions shall be observed:
(5) Personnel safety. The following safety precautions shall be observed:
(6) Equipment requirements. (i) Fiber optic splices shall be made in areas where temperature, humidity, and cleanliness can be controlled. Both fusion and mechanical splicing techniques may require a splicing vehicle equipped with a work station that will allow environmental control.
(7) Cable preparation. (i) Engineering work prints shall prescribe the cable slack needed at splice points to reach the work station inside the splicing vehicle. Consideration should be given to the slack required for future maintenance activity as well as initial construction activities. The required slack may be different for each splice point, depending on the site logistics. However, the required slack is seldom less than 15 meters (50 feet). The amount of slack actually used shall be recorded for each splice point to assist future maintenance and restoration efforts.
(8) Shield bonding and grounding. For personnel safety, the shields and metallic strength members of the cables to be spliced shall be bonded together and grounded before splicing activities are started. (See paragraphs (g)(4), and (g)(5)(i) through (g)(5)(iii) of this section for final bonding and grounding provisions).
(9) Fiber optic color code. The standard fiber optic color code for buffer tubes and individual fibers shall be as shown in Table 7:
Table 7—Fiber and Buffer Tube Identification
5 Slate.
8 Black.
9 Yellow.
10 Violet.
11 Rose.
12 Aqua.
13 Blue/Black Tracer.
14 Orange/Black Tracer.
15 Green/Black Tracer.
16 Brown/Black Tracer.
17 Slate/Black Tracer.
18 White/Black Tracer.
19 Red/Black Tracer.
20 Black/Yellow Tracer.
21 Yellow/Black Tracer.
22 Violet/Black Tracer.
23 Rose/Black Tracer.
24 Aqua/Black Tracer.
(10) Buffer tube removal. (i) The splice case manufacturer's recommendation shall be followed concerning the total length of buffer tube to be removed. Identify the length to be removed with plastic tape.
(11) Coated fiber cleaning. (i) Each coated fiber shall be cleaned. The cable manufacturer's recommendations shall be followed concerning the solvent required to clean the coated fibers. Reagent grade isopropyl alcohol is a commonly used cleaning solvent.
(12) Fiber coating removal. (i) Fiber coatings shall be removed. In accordance with the splicing method used, the splice case manufacturer's recommendation shall be followed concerning the length of fiber coating to be removed.
(13) Bare fiber cleaning. After the fiber coating has been removed, the bare fibers shall be cleaned prior to splicing. Each fiber shall be wiped with a clean tissue or cotton ball soaked with the cleaning solvent recommended by the cable manufacturer. The bare fiber shall be wiped one time to minimize fiber damage. Aggressive wiping of bare fiber shall be avoided as it lowers the fiber tensile strength.
(14) Fiber cleaving. Cleaving tools shall be clean and have sharp cutting edges to minimize fiber scratches and improper cleave angles. Cleaving tools that are recommended by the manufacturer of the splicing system shall be used.
(15) Cleaved fiber handling. The cleaved and cleaned fiber shall not be allowed to touch other objects and shall be inserted into the splicing device.
(16) Completion of the splice. (i) In accordance with the method of splicing selected by the borrower, the splice shall be completed by either fusing the splice or by applying the mechanical connector.
(17) Fiber optic testing. Fiber optic testing shall be performed in accordance with RUS Bulletin 345-63, “RUS Standard for Acceptance Tests and Measurements of Telephone Plant,” PC-4, (Incorporated by reference at §1755.97).
(18) Cable acceptance. Installed cable shall be tested and pass the inventory and acceptance testing specified in the Telephone System Construction Contract (Labor and Materials), RUS Form 515. The tests and inspections shall be witnessed by the borrower's resident project representative.
(f) Splice arrangements for fiber optic cables—(1) Aerial splices. Cable slack at aerial splices shall be stored either on the messenger strand, on the pole, or inside a pedestal at the base of the pole. A typical arrangement for the storage of slack cable at aerial splices is shown in Figure 9:
(2) Buried splices. Buried splices shall be installed in handholes to accommodate the splice case and the required splicing slack. An alternative to the handhole is a pedestal specifically designed for fiber optic splice cases. Typical arrangements for buried cable splices are shown in Figures 10 and 11:
(3) Underground manhole splices. Underground splices shall be stored in manholes on cable hooks and racks fastened to the manhole wall. The cable slack shall be stored on cable hooks and racks as shown in Figure 12:
(4) Central office cable entrance. (i) Filled cable or filled splices are not recommended for use inside central offices except in cable vault locations. Outside plant cable sheath and cable filling compound are susceptible to fire and will support combustion. Fire, smoke, and gases generated by these materials during burning are detrimental to telephone switching equipment.
(g) Bonding and grounding fiber optic cable, copper cable, and copper service wire—(1) Bonding. Bonding is electrically connecting two or more metallic items of telephone hardware to maintain a common electrical potential. Bonding may involve connections to another utility.
(2) Copper cable shield bond connections. (i) Cable shields shall be bonded at each splice location. Only RUS accepted cable shield bond connectors shall be used to provide bonding and grounding connections to metallic cable shields. The shield bond connector manufacturer's instructions shall be followed concerning installation and use.
(ii)(A) Shield bonding conductors shall be either stranded or braided tinned copper wire equivalent to a minimum No. 6 American Wire Gauge (AWG) and shall be RUS accepted. The conductor connections shall be tinned or of a compatible bimetallic design to avoid corrosion problems associated with dissimilar metals. The number of shield bond connectors required per pair size and gauge shall be as shown in Table 8:
Table 8—Shield Bond Connectors per Pair Size and Gauge
50-100 150-300 200-400 300-600 2
150-200 400-600 600-900 900-1500 3
300-600 900-1200 1200-2100 1800-3600 4
(3) Buried service wire shield bond connections. Buried service wire shields shall be connected to the pedestal bonding and grounding system. Typical buried service wire installations are shown in Figures 17 and 18. In addition to the methods referenced in Figures 17 and 18, the shields of buried service wires may also be connected to the pedestal bonding and grounding system using buried service wire bonding harnesses listed on Page 3.3.1, Item “gs-b,” of RUS Bulletin 1755I-100. RUS Bulletin 1755I-100 may be purchased from the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402. When those harnesses are used they shall be installed in accordance with the manufacturer's instructions. Figures 17 and 18 are as follows:
(4) Fiber optic cable bond connections. (i) The cable shield and metallic strength members shall be bonded at each splice location. Only RUS accepted fiber optic cable shield bond connectors shall be used to provide bonding connections to the metallic cable shields. The shield bond connector manufacturer's instructions shall be followed concerning installation and use.
(5) Grounding. (i) Grounding is electrically connecting metallic telephone hardware to a National Electrical Safety Code (NESC) acceptable grounding electrode. Acceptable grounding electrodes are defined in the Rule 99A of the NESC.
(6) Bonding and grounding splice cases. (i) Splice cases are equipped with bonding and grounding devices to ensure that cable shields and metallic strength members maintain electrical continuity during and after cable splicing operations. The splice case manufacturer's recommendations shall be followed concerning the bonding and grounding procedures. Conductors used for bonding shall be either stranded or braided tinned copper wire equivalent to 6 AWG. Conductors used for grounding shall be a solid, bare, copper wire equivalent to minimum No. 6 AWG.
(7) Bonding and grounding central office cable entrances. The RUS Telecommunications Engineering and Construction Manual (TE&CM) Section 810 provides bonding and grounding guidance for central office cable entrances. Splicing operations shall not be attempted before all metallic cable shield and strength members are bonded and grounded.
[60 FR 5097, Jan. 26, 1995; 60 FR 9079, Feb. 16, 1995]