260400-UindergroundControlCablePowerDist-20110512.pdf

Telecommunications and Wiring Specifications 26 04 00 AG-05G1-S-11-0021

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Underground Power and Cable Distribution

SECTION 26 04 00

UNDERGROUND CABLE

1. PART 1 - GENERAL

1.01 DESCRIPTION

A. These specifications provide for installation of underground power conductors and cables, using trenching methods, conduit and underground secondary service.

1.02 REFERENCES

A. 02 3180 Excavation and Backfill for Utilities

B. 26 0010 General Technical Provisions

C. 26 0050 Basic Materials and Methods

D. 26 0115 Specialized Electrical Materials

1.03 SUBMITTALS

A. Submit shop drawings and equipment catalog data and manufacturer's installation operating and maintenance instructions for approval of the following items in accordance with

Section 260010:

B. Provide both hard copy and manufacturer’s original PDF files with submittals in electronic form with items marked to be submitted with all accessories.

C. Submit three copies of the following:

1. Conductor and Cable: Catalog data, cuts showing conductor and cable construction, thicknesses and material

2. Power and Cable Splices: Catalog data showing construction of all materials and installation procedures.

3. Splice Vault: Catalog data and shop drawings.

4. Metallic Core Marking Tape: Catalog Data.

5. Nameplates for cable identification provide engraving list with submittal.

1.04 QUALITY ASSURANCE

A. Follow the latest edition of the National Electrical Safety Code and NEC except where local regulations are more stringent.

B. Provide certifications that persons who install and terminate and splice underground cable have experience in the telecommunications field and have terminated and splices these cables.

1.05 DELIVERY, STORAGE AND HANDLING

A. Protect all material and equipment to be incorporated in construction from the elements.

B. Handle cable carefully at all times to avoid damage. Excessive bending of the cable will not be permitted.

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C. Seal the ends of the cable against moisture at all times with suitable end caps. Where it is necessary to cut the cable, terminate or seal ends immediately after the cutting operation.

2. PART 2 - PRODUCTS

2.01 CONDUITS

A. Install all communications, telephone, and fiber optic cables in conduit as shown on drawings.

B. See 26 00 50 for conduit types and construction materials.

2.02 POWER CONDUCTORS – UNDERGROUND INSTALLED IN CONDUIT

A. Conform to REA Specification (XLP-USE insulation, cross-linked polyethylene) U-1 for primary and U-2 Type 2 for 600 volt secondary unless otherwise shown on the drawings, and as described below.

B. All conductor-sizes on drawings are for copper conductors. Aluminum will not be allowed.

2.03 METALLIC CORE MARKING TAPE

A. Furnish plastic covered aluminum marking tape for power and conductors.

B. Tape width: 2".

C. UNDERGROUND DETECTABLE - 5 MIL 2 Mil Polyethylene Film Reverse Printed and

Laminated To Aluminum Foil Then Laminated To 2 Mil Polypropylene Film

D. Color: Power- Red, Telecommunication Cable-Orange.

E. Inscription: 25 pr Telephone Line "Caution, Buried Telephone Line", Fiber Optic

"Caution, Buried Fiber Optic Line" or as approved by the Contracting Officer

1. Orange

3. PART 3 - EXECUTION

3.01 INSPECTION AND INVENTORY OF BURIED POWER AND CABLE

A. Before any backfilling operations are begun, the Contractor and Contracting Officer shall jointly inspect all trenches, cable placement, splice vaults, risers, and other construction not accessible after backfilling.

3.02 PREPARATION

A. Trenching shall conform to Section 31 20 00.

3.03 POWER AND CABLE INSTALLATION

A. Conduit Cleaning

1. Prior to pulling cable thru conduits clean all conduits by swabbing out conduits to remove all debris.

B. Placing of Cable in Trenches: Do not lay cable when the outside temperature is below the minimum temperatures specified by the cable manufacturer.

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1. Power, communications cable and fiber optic cable shall be installed in conduit only.

Direct burial is not allowed.

2. Wherever possible, cable shall be played out from the reel mounted on a moving vehicle or trailer. Support the reel on a stand. Place cable in the trench by hand.

3. Inspect the cable as it is removed from the reel in laying operations to be certain that it is free from visible defects.

4. Cable pulled through conduit; duct or other locations shall be lubricated with a suitable cable lubricant prior to pulling into conduit or duct.

5. Do not exceed cable pulling tension as recommended by manufacturer.

a. Provide a pulling dynamometer to measure pulling tension on all pulls.

6. Leave a minimum of 24" slack on each cable at all risers, splices, transformer pads, pedestals and terminal points.

C. Cable Minimum Bending Radius: Measure radius to the surface of the cable on the inside of the bend.

1. Secondary service cable (600V or less) 6 times the overall diameter of the cable.

2. Primary cable (more than 600V) 12 times the overall diameter of the cable.

3. Cable - three feet radius.

D. Splices: Not more than one splice for each 2000' of power or cable installed in any one continuous run.

1. Make Cable splices in accordance with the manufacturer's instructions.

2. Provide written certification those persons making the splice on buried cable have demonstrated previous experience in splicing underground telephone cable.

3. Splice details are shown on the drawings.

4. Use pre-formed molded case poured "potted" splice kits installed in accordance with manufacturer's recommendations. See Section 260050.

5. Make all splices in splice vaults or at pedestals. Vaults or pedestals shown on drawings are the minimum number required.

6. Bends will not be permitted within 12 inches of the ends of splice.

7. The cable or circuit numbers and the exact location of the splices shall be noted and given to the Contracting Officer.

3.04 PULLING STRESSES

A. Maximum 500 pounds as measured by a dynamometer or less if recommended by cable manufacturer.

B. Do not use pulling eyes or other attachments connected directly to the conductor.

3.05 BACKFILLING

A. Conform to Section 31 20 00

B. Provide electrical bedding material on all conduits installed in trenches for 6” surrounding conduits.

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3.06 CONDUIT

A. All exposed ends of conduit shall be plugged during construction.

B. Remove burrs or sharp projections that might injure the cable.

3.07 TERMINATIONS TELEPHONE AND FIBER OPTIC CABLE

A. Make terminations in accordance with the manufacturer's instructions.

3.08 CABLE TERMINATIONS AND ROUTING

A. Provide bundling of all cable by binder groups and route input and output cables to lightning arrestors so that cable paths do not cross. Keep input and output cables separated to lightning protectors.

3.09 CABLE FILLING COMPOUND CLEANING

A. Clean all pairs of cable at each splice and termination of filling compound with solvent, not harming insulation approved by cable manufacturer.

3.10 BENDS

A. No bends shall be permitted within six inches of the ends of stress cones.

3.11 IDENTIFICATION OF CABLES

A. In each pull / slice vault and at each termination, provide engraved plastic nameplates tie wrapped to conduit in all splice and pull vaults or to wall if in buildings to identify the cable as follows on each nameplate:

1. Circuit Voltage, phase, cable size either in AWG or cable pair number and AWG size, source and termination of each cable.

B. See 260010 for nameplate construction and lettering height

3.12 CABLE MARKERS

A. Mark power and cable location with permanent cable markers 200 feet maximum interval and at all changes in direction greater than 30 degrees.

B. Provide cable direction marker as shown on drawings.

C. Install two-inch wide labeled metallic core plastic warning tape above cables as shown on drawings. Provide a separate marking tape for power cable and a separate tape for cable.

3.13 TESTS

A. Conduct tests in the presence of the Contracting Officer on each length of direct burial power and cable in the system, with terminations in place but disconnected. See Section

16010 TESTS for test report format and general provisions. These tests apply to cable direct buried or pulled in conduit.

B. Provide an independent testing firm(s) that specializes in testing power and telephone cable, with demonstrated minimum of 3 years in testing cable. Provide the appropriate testing equipment for high-pot, continuity and insulation resistance testing, and for fault locating.

C. Preliminary Continuity and Insulation Resistance (Power Cable): After installation of the power cable and prior to backfilling and the high potential test specified below, perform

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05/12/2011 Telecommunication and Wiring 26 04 00 - 5/8 a simple continuity test on the system by shorting each conductor pair together at the source and checking for continuity from the end of each tap or line with an ohmmeter. Megger each conductor to ground (includes neutral) and to each other conductor to test for insulation faults prior to doing hipot tests below. See 26 00 10 PRELIMINARY TESTS for insulation requirements. Ground one lead to a 5 foot driven ground rod and connect the other lead to conductor with terminations disconnected. Measure insulation resistance to ground and between phases with a DC Megger, 2,500 VDC, prior to doing hi pot test described below. After backfilling perform high - pot tests described below.

D. Continuity and Insulation Resistance (Cable): After installation, and prior to backfilling, perform a test on each separate length of cable, and after any splice or tap is made on the whole length of the cable from the source to each termination prior to encapsulation of splice. Repeat tests after encapsulation and placement of backfill. All cable pairs must pass insulation and continuity tests described below.

E. Cable Insulation Resistance Test: Measurements with digital type ohmmeter with a

10,000 megohm minimum scale range, Fluke 189 or equivalent. Limit test voltage to 10 volts D.C. (Fluke meets this requirement).

3.14 CABLE INSULATION RESISTANCE: TEST PROCEDURE

A. Disconnect all cable conductors and shields at both ends.

B. If this cable has two shields they should be tied together and treated as one shield for testing purposes. Scrape off plastic coating when connecting shields together.

C. Drive a 5-foot ground rod near cable end test point.

D. Set voltmeter to the 200 D.C. millivolt range.

E. Measure the voltage between the shield and ground rod, and record. The voltage should be less than .01 volts (ten millivolts). If the voltage is more than .01 volts, this indicates cracks or cuts in the outer cable insulation, which must be repaired before the remaining tests are performed. If the measured voltage is less than .01, proceed to the next step.

F. Set meter to the 200 nanoseimen range. .

G. Note: To convert nanoseimens to megohms, use the following formula:

H. Megohms = 1,000/ns. Reading - 1.0 then megohms - 1,000/1.0 = 1,000 or use conversion chart supplied with Fluke meter.

I. Measure and record insulation resistance between:

1. Each conductor and every other conductor.

2. Each conductor and cable shield.

3. Each conductor to the ground rod, for cables installed in conduit ground shield after this test is done and repeat the tests.

4. Cable shield to the ground rod. For cables installed in conduit perform this test.

J. All individual resistance measurements shall exceed 5,280 KFTM (kilofoot-megohms).

K. KFTM. (Insulation Resistance) = Length of cable in kilofeet x measured resistance in megohms. 1 kilofoot (KFT) = 1,000 ft.

L. Example:

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1. Cable length = 2,640 feet (2.640 KFT), Measured resistance of cable shield to ground rod = 2,400 megohms; so, Insulation Resistance (KFTM) = (2.640) KFT x (2,400) megohms = 6,336 KFTM.

2. This is acceptable, as it exceeds the minimum of 5,280 kilofoot-megohm specification.

3.15 CABLE CONTINUITY TEST

A. Make measurements with digital type ohmmeter with a 10,000 megohm minimum scale range, Fluke 189 or equivalent. Limit test voltage to 10 volts D.C. (Fluke meets this requirement).

B. Procedure

1. Disconnect all cable conductors at both ends.

2. Short both conductors of each pair together at one end of cable.

3. Set meter to measure resistance in the expected range, and measure the resistance of each pair in the cable at the opposite end, and record.

4. The resistance of any pair should not exceed 38 ohms for each 1,000 feet of #22

AWG CU., cable tested.

5. Acceptable measured pair resistance = (cable length in feet) divided by 1,000 x (38 ohms per 1,000 feet).

C. Example:

1. Cable length = 1,255 feet, Measured resistance = 45 ohms. so, (1,255/1,000 x (38) =

47.69 ohms. (acceptable maximum)

2. Actual measured resistance = 45 ohms and is acceptable because this is less than maximum specified resistance allowable.

3.16 CABLE INSTALLATION PRECAUTIONS

A. For cable protection, conduit containing cable should be surrounded by at least 6 inches of fine sand. Care must be taken to prevent damage to the cable or insulation by falling rocks, sharp shovels or other tools, crushing by heavy equipment or machinery.

B. The insulation thickness is only .045" and a small puncture of the insulation will allow moisture and contaminates to contact the shield material, causing electrolysis which will eventually destroy the shield of the cable. More and more moisture enters over a period of time and finally the cable has to be replaced.

C. Insulation cuts or puncture faults without damage to the shield or conductors may be encased in a poured resin type splice container (without splicing) in lieu of replacing cable.

If a splice is made a splice vault must be installed.

3.17 CABLE FAILURES

A. Cable and splices that do not meet the above tests shall be corrected either by replacement or splice and the test procedure repeated until cable/splice meet test requirements. Replace defective length of cable and splice in new length using cast in-line re-enterable splice enclosures. Splice shall be installed in splice vault or made at a pedestal.

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3.18 HIGH POTENTIAL (POWER CABLE)

A. After successful continuity, insulation resistance tests and backfilling, perform high potential tests on each length of cable in the system.

B. Maintain for a minimum of five minutes a DC test potential of 240 percent of the final factory AC test voltage as follows:

C. 600 volt Secondary Cable

1. XLP-USE Insulation

Size Insulation

Thickness

Final Factory AC

Test

Field DC

Acceptance

6-2 0.060 4.5kV 10.8kV

1-4/0 0.078 5.5kV 13.2kV

AWG or MCM Inches Voltage Test Volts

250-500 MCM 0.094 6.8kV 16.3kV

600-1000 MCM 0.109 7.8kV 18.9kV

D. Primary Cable

1. XLP-USE INSULATION

2. Rated Voltage

AWG or MCM Inches Voltage Test Volts

15kV 0.175 22.0kV 52.8kV

25kV 0.260 32.5kV 78.0kV

E. The voltage may either be increased continuously or in steps to the maximum test value.

F. If increased continuously, increase uniformly to maximum voltage in not less than 10 seconds and in not more than approximately 60 seconds. Apply maximum test voltage for a total of five minutes.

G. If applied in steps, increase from one step to the next uniformly with each step long enough for the absorption current to attain reasonable stabilization (one minute minimum). Take current and voltage readings at the end of each step duration. The number of steps shall be from five to eight.

H. Plot leakage current in microamps DC vs. test voltage. Continue plot for five minutes.

I. Correct point faults by enclosing fault area in cast in-line splice enclosure, WITHOUT

SPLICING. If wire is damaged remove section damaged and splice in new wire with in-line compression splice lugs and poured urethane splice as above.

J. Install any splice or fault area described above in a splice vault or pedestal.

K. All faults discovered by this test shall be corrected and the tests rerun until cable splice meet requirements.

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L. Warning: Following these tests, a hazardous voltage may exist on the power cable. The conductor shall be grounded to permit any charge to drain to earth.

END OF SPECIFICATION 26 04 00