6. Scope of Work and Detailed Specifications
6.6. Technical Requirements / Scope of Work
6.6.2. Cable: Single Conductor ,Copper, Mv-105,15,000 Volt
This specification states the requirements for a single conductor copper, 15,000 volt cable for use on single or three phase, 60 cycle, alternating current underground circuits between medium voltage transformers. The cable shall be classified as MV-105 per Underwriter’s Laboratories.
6.6.2.2.
Industry Standards
American Society for Testing and Materials - ASTM Association of Edison Illuminating Companies - AEIC Insulated Cable Engineers Association - ICEA
National Electrical Manufacturer’s Association - NEMA Underwriters Laboratories - UL
6.6.2.3.
Referenced Standards
The cable must conform in detail to the requirements stated herein and to the latest edition of ICEA S-93-639 (NEMA WC-74), ICEA S-97-682, UL1072 and AEIC CS8-00.Cable not conforming to this specification will not be accepted.
6.6.2.4.
Construction
The completed cable must consist of a stranded copper conductor, strand screen, EPR insulation and insulation shield all applied in a triple tandem extrusion process. A copper tape shield and a PVC jacket must be applied overall.
Cables shall be suitable for operation in wet or dry locations and must be rated 105º Centigrade for continuous operation, 130º Centigrade for overload operation and 250º Centigrade for short circuit conditions.
Cables must be UL listed at 15 KV, 133% insulation level and be classified as MV-105 (medium voltage - 105º). Cables shall be free of insulation and/or jacket repairs.
6.6.2.5.
Conductor
The conductor must be soft drawn annealed round copper wire.
The conductors must be concentric lay with a Class B stranding in accordance with ASTM B3 and B8. The conductor size will be No. 2 AWG, No. 1/0 AWG or other sizes as noted in proposal.
6.6.2.6.
Strand Screen
The conductor strand screen must be a black extruded, semi-conducting, thermosetting compound. It must be free stripping from the conductor and inseparably bonded to the overlying insulation.
The minimum thickness of the strand screen must be 2.5 mils. The thickness of the strand screen shall not be considered a part of the insulation thickness.
The conductor strand screen must comply with the requirements of ICEA S-93-639, ICEA S-97-682, and UL 1072.
6.6.2.7.
Insulation
The insulation must be a black thermosetting ethylene-propylene rubber (EPR) per ICEA S-93-639 (NEMA WC-74), AEIC specification CS8-00 and UL 1072, or latest revisions thereof.
The insulation must be circular in cross section, concentric to the conductor and must have an average thickness of 220 MILS (per 133% insulation level) with a minimum thickness not less than 90% of the average.
Initial physical requirements.
1. Tensile strength, Min., PSI 1200
2. Elongation at rupture, Min. % 250
After conditioning in an air over at 121+ 1oC for 168 hours using methods of test described in ASTM-D 573:
Tensile strength, minimum percent of unaged value 90
Elongation at rupture, minimum percent of unaged value 90
After 168 hours in water at 70 + 1oC, maximum water absorption must be:
Milligrams per square inch 5.0
At 15.6oC :
Maximum % P.F. @ 80 V/Mil 1.0
6.6.2.8.
Insulation Screen
A tight constricting envelope of black semi-conducting thermosetting material must be applied over the insulation. This covering shall conform to the contour of the insulation surface following non-uniformities and shall exclude air pockets adjacent to the insulation. It shall have resiliency to follow the expansion and contraction cycles of the cable remaining in constant contact with the insulation. The compounds chemical and mechanical compatibility with the insulation must be evidenced by compliance with the requirements of the cyclic aging and resistance stability tests per AEIC CS8-00.
The insulation screen must meet the requirements of ICEA S-93-639, NEMA WC-74, AEIC CS8-00 and UL 1072 or the latest revisions thereof.
The screen must strip freely from the insulation and, when removed, must not leave any conducting particles, deposits or other residue on the surface of the bared insulation.
The guaranteed peel strength of the screen from the insulation must be between 6 and 24 pounds per half inch width when tested per AEIC CS8-00 or latest revision thereof.
6.6.2.9.
Copper Tape Shield
The insulation screen must be covered with a metallic tape shield applied helically with a 25 percent overlap. The metallic tape must be uncoated, non-magnetic, copper, per ICEA S-93-639. The tape must be 5 mils in thickness.
6.6.2.10. Jacket
The jacket must be a black polyvinyl chloride (PVC).
The jacket thickness must be a minimum of 80 mils average, with no spot less than 90% of the average. The jacket must have the following physical properties:
1. Unaged Physical:
Tensile (PSI) 1500
Elongation (%) 100
2. After air oven for 120 hours @ 100oC:
Tensile (% of unaged) 85
Elongation (% of unaged) 60
3. After immersion in #2 oil for 4 hours @ 70oC:
Tensile (% of unaged) 80
Elongation (% of unaged) 60
4. After air oven for 1 hour @ 121oC:
Heat Distortion (% max) 50
5. After 168 hours @ 70oC:
Gravimetric water absorption (max. MG/IN2) 20
6.6.2.11. Testing
All cable produced under this specification will be subject to testing. Tests must be performed as required by ICEA S-93- 639, CS8-00, and UL 1072.
Tests must include conductor DC resistance, high voltage, insulation resistance, cold bend test, corona test per CS8-00, water absorption test, and any other tests that may be specified to insure the produced cable meets these specifications.
Tests must be performed on samples taken from completed cable. One (1) sample must be taken for each 5,000 feet or fraction thereof.
Any reel which fails to conform to these test requirements will be rejected.
6.6.2.12. Identification
On the black PVC jacket, at approximately two (2) foot intervals, the following information must be printed with permanent, white, contrasting ink:
1. Name of Manufacturer 2. Date of Manufacture 3. Wire size
4. 15KV, CU, 220 Mil EPR, 80 Mil PVC. 5. (UL) MV-105
On the PVC Jacket, on the side opposite the legend, at one (1) foot intervals, the manufacturer must print sequential footage.
6.6.2.13. Packaging
All cable must be shipped on sound, substantial, non-returnable reels with a three inch (3") steel reinforced arbor. Two 1/C cables must be parallel wound on each reel. Both cable ends must be readily accessible so that both conductors can be readily installed with a one reel set-up. Both ends of each length of cable shall be properly sealed against the entrance of moisture and other foreign matter. The ends must be securely fastened so as not to become loose in transit.
All reels must be 100% lagged with 2"x4" wood lagging.
Reel size must be a maximum of 76" high x 40" wide. The reel core diameter must be based on the minimum bending radius of the cable but must not be smaller than 36".
It is desirable that reels contain 2,500 linear feet per conductor but in no case may the maximum gross reel weight exceed 4,500 pounds.
A metal tag(s) must be securely fastened to each reel indicating the reel number; gross and tare weights; a description of the cable; directions for unrolling the cable; the total footage of cable on the reel; and the beginning and ending sequential footage numbers on the reel for each cable.