Electrical Underground Work

	Title			Page

Purpose			2
Scope			2
Related Documents			2
Materials and Equipment			3
		General	3
		Conduit	3
		Grounding Equipment	4
Installation Procedures			4
		General	5
		RNC Conduit	5
		Concrete Encased RNC Conduit	5
		Direct Burial RNC Conduit	5
		Metallic Conduit	7
Direct Buried Cable			7
		General	7
		Cable Mechanical Protection	8
		Medium Voltage Direct Buried Cable (Over 600V)	8
Inspections and Testing			9
		Inspections	9
		Testing	9
		Grounding Electrode System Testing	10
		Low Voltage Cable Testing	10
		Medium Voltage Cable Testing	10
		Documentation	10
		Insulation Resistance Test Results	11
		Grounding System Resistance Test Report	12

This technical specification and method statement outline the requirements for the installation of underground electrical work. It sets the standards, responsibilities, and procedures for the project. Here are key points from the provided information:

Scope of Work: This article covers the installation, testing, and materials required for underground electrical work. It is intended for use by the engineering contractor or installer responsible for the project.

Engineering Contractor’s Responsibilities: The engineering contractor is responsible for providing all the necessary resources, including labor, tools, materials, and equipment, to complete the underground electrical system installation. They must ensure that the work complies with the contract drawings, this specification, relevant codes and standards, manufacturers’ instructions, and the guidance of the field representative.

Conflict Resolution: In case of conflicts or discrepancies between different sources of information, such as codes, specifications, or contract drawings, the field representative engineer should be promptly notified. Resolving such conflicts is crucial to ensure that the project proceeds smoothly and meets all necessary requirements.

Qualifications: The work should be carried out by a qualified electrical contractor or a civil contractor with the necessary qualifications to perform electrical work. This emphasizes the importance of hiring skilled and certified professionals for the job.

This article serves as a foundation for the underground electrical work, outlining responsibilities, conflict resolution procedures, and qualifications required for the project’s successful execution. It ensures that the work adheres to safety standards and industry best practices.

4WCE-600001 General Scope of Work for Construction Contracts

4AEL-620112 Commissioning: Grounding Systems

STD-P320A Electrical Standard Direct Buried High-Voltage Cables

4AEL-620303 Installation and Testing of Medium Voltage Cable

3.2 American Foundrymen’s Society (AFS)

Sand Testing Manual

American Society for Testing and Materials (ASTM)

D698 Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Standard Effort

3.4 Institute of Electrical and Electronic Engineers (IEEE)

81 Guide for Measuring Earth Resistivity, Ground Impedance, and Earth Surface Potentials of a Ground System

837 IEEE Standard for Qualifying Permanent Connections Used in Substation Grounding

3.5 National Fire Protection Association (NFPA)

NFPA 70 National Electrical Code (NEC)

3.6 NETA International Electrical Testing Association

ATS-2007 Standard for ACCEPTANCE TESTING SPECIFICATIONS for Electrical Power Equipment and Systems

4. MATERIALS AND EQUIPMENT

4.1 General

This section outlines the quality requirements for equipment and materials provided and installed by the engineering contractor in the context of electrical work. Here are the key points:

4.1.1 Quality Requirements:

All equipment and materials supplied and installed by the engineering contractor must meet high-quality standards. They should be free from defects, imperfections, and should be of recent manufacture.
The provided equipment and materials must be new, unused, and meet the classification and grade specified in the project’s specification or contract drawings.
Whenever possible, electrical materials and equipment should be labeled by Underwriters’ Laboratories, Inc., indicating compliance with safety and quality standards.

4.1.2 Substitutions:

The contract drawings and specifications include manufacturers’ catalog numbers to establish the required grade and quality for materials and equipment.
While equivalent materials or equipment from other manufacturers may be considered for substitution (unless marked “No Substitution”), any proposed substitutions should adhere to a specified process outlined in document 4WCE-600001.

4.1.3 Hazardous Areas:

Equipment and materials intended for use in areas classified as electrically hazardous must be approved for such use and installed in an approved manner.
All equipment and devices used in these areas should bear appropriate approval labels indicating their suitability for hazardous locations.
If the contract drawings do not specify the location as hazardous, it should be assumed that the installation is in a nonhazardous area.

These guidelines emphasize the importance of using high-quality materials and equipment, adhering to safety standards, and considering approved substitutions when necessary to meet project requirements. Additionally, they highlight the need for specific approvals and labels when working in electrically hazardous areas.

4.2 Conduit

This section outlines the specifications for conduit types to be used in the project. Here are the key points:

4.2.1 Conduit Types:

The default conduit type for this project is specified as “Rigid Nonmetallic Conduit (RNC)” unless otherwise indicated.
The document provides descriptions for various conduit types that may be specified on the contract drawings. These include:
Rigid Metal Conduit Type RMC (Steel): This type of conduit, along with associated fittings, should have an outer zinc protective coating and an inner protective coating made of zinc, enamel, or an equivalent corrosion-resistant material.
Rigid Metal Conduit Type RMC (Aluminum): Conduit, fittings, and associated components in this category should be made of a corrosion-resistant aluminum alloy containing no more than 0.4% copper.
Rigid Nonmetallic Conduit (RNC): This should be Schedule 40, 90°C wire-rated, heavy-wall rigid plastic conduit. The specification mentions a specific brand, “Carlon or equal.”

The document specifies that unless otherwise noted in the contract drawings, Rigid Nonmetallic Conduit (RNC) is the default choice for conduit material. It also provides detailed requirements for other conduit types when they are specified.

This section ensures clarity regarding the types of conduit to be used in the project and outlines specific requirements for each type, including materials and coatings for metal conduits and the specifications for nonmetallic conduit.

4.3 Grounding Equipment

This section outlines the specifications for grounding materials and installation methods. Here are the key points:

3.1 Ground Rods:

Ground rods used in the project should have a copper surface over a steel center, with a diameter of 19 mm (3/4 in) and a length of 3 m (10 ft). This type is commonly referred to as “Copperweld.”
When ground rods longer than 3 m (10 ft) are required, they should be assembled using threaded couplings.
The contractor is responsible for providing all the necessary driving studs for the ground rods.

4.3.2 Ground Wire:

Ground wires must be made of bare, soft-drawn stranded copper with a conductivity of 100% International Annealed Copper Standard (IACS) at 20°C.
All ground wires should be buried at a minimum depth of 750 mm (2 ft 6 in) below the finished grade.
Specific burial depth and conductor sizes should be referenced in the contract drawings.

4.3.3 Underground Splices and Connections:

Underground splices and connections should be made using one of the specified methods and manufacturers. No substitutions are allowed. The approved connection methods are:
Cadweld process by ERICO Products, Inc.
Burndy “Hy-Ground” TM compression system (calibration tests required).
Panduit “STRUCTUREDGROUNDTM” Direct Burial Compression Grounding System (calibration tests required). Crimps should use the 3-step enhanced process to meet IEEE Std 837. Only Panduit dies and approved tools should be used.

4.3.4 Testing and Inspection:

Section 7 of the document covers the required inspections and testing of the grounding system and components before concrete is poured or trenches are backfilled. Ground rods must be tested before connecting them to the ground grid.

4.3.5 Grounding Pigtails for Aboveground Connections:

Grounding pigtails used for aboveground connections should extend a minimum of 3 m (10 ft) beyond the finished grade level, unless otherwise specified in the contract drawings.
Pigtails should be coiled and adequately protected to prevent damage and reduce the risk of becoming a tripping hazard.

These specifications ensure that the grounding system is installed correctly and meets safety standards, and they provide guidance on materials and methods to achieve this.

5. INSTALLATION PROCEDURES

5.1 General

This section outlines the general requirements and procedures for conduit installation. Here are the key points:

5.1.1 Conduit Installation:

Conduit installation should adhere to the contract drawings, the National Electric Code (NEC), local codes, and this specification.
In case of conflicting requirements, the most stringent ones should be followed.
The conduit installation and routing should match the contract drawings. Any deviations in routing must be approved by the Air Products representative and documented in as-built drawings.

5.1.2 Conduit Elbows:

Conduit elbows up to 40 mm (1 1/2 in) trade size should be standard radius or field bent conduit with the radius of standard elbows.
Larger conduit sizes should have minimum bending radii as specified to facilitate cable pulling.

5.1.3 Wall Openings for Ducts or Conduits:

When walls, such as pit, retaining, manhole, or handhole walls, are poured before ducts or conduits’ installation, windows should be boxed out in the wall with water stops.
The window openings should be filled with “Ceilcote EJ4” non-shrinking grout around ducts or conduits to create a watertight joint with the wall.
The inside of the opening should be finished smoothly and flush with the wall.

5.1.4 Inspections and Testing:

Section 7 of the document provides information on required inspections and testing before pouring concrete or backfilling trenches.

5.1.5 Mandrel Testing:

After ducts have been concrete-encased or backfilled, a mandrel should be passed through them to clean out dirt and moisture, verify orientation, and ensure there are no obstructions.
This procedure should be witnessed, approved, and logged by the Air Products field representative.
If the mandrel fails to pass through a duct, it must be exposed, and defects corrected.
Weatherproof plugs with fish tape eyelets should be used to cap conduits after successful testing to prevent the entry of dirt and moisture.
A calibrated fish tape should be installed in each conduit and properly fastened at the conduit plugs, with a minimum of 1 m (3 ft) of extra line at each end.

5.1.6 Conduit Stub-Ups:

Conduit stub-ups should be plumb within a 3 mm (1/8 in) tolerance per foot of conduit.
A 3 m (10 ft) conduit extension should be installed and secured during pouring to ensure and maintain plumbness.
Conduit stub-ups should be located within 25 mm (1 in) of the position shown on the contract drawings, except for stub-ups under electrical equipment and control panels, where a maximum tolerance of 6 mm (1/4 in) is allowed.

These specifications provide guidelines for proper conduit installation, ensuring that conduits are correctly routed, supported, and tested to meet project requirements and safety standards.

	Size	Bending Radius
	50 mm (2 in) and 65 mm (2 1/2 in)	minimum 600 mm (24 in)
	75 mm (3 in) and 90 mm (3 1/2 in)	minimum 900 mm (36 in)
	100 mm (4 in) and 125 mm (5 in)	minimum 1200 mm (48 in) on horizontal bends only

5.2 RNC Conduit

5.2.1 General

This section outlines the general guidelines for the installation of RNC (Rigid Nonmetallic Conduit) conduit:

5.2.1 General:

Solvent Cementing: All joints in RNC conduit should be solvent cemented according to the manufacturer’s recommendations. There should be visible evidence that the solvent has been applied to the fitting edge.
Conduit Terminations: Conduit terminations in manhole walls or building floors under free-standing electrical equipment should use duct bell ends and be flush with the finished surface.
Field Bends: All field bends should be made using heater box bending equipment, following the manufacturer’s recommendations.
Above-Grade Transition: When a conduit needs to extend above grade to reach utilization equipment, a below-grade transition from RNC to RMC (Rigid Metal Conduit) is required. This transition should include an RMC elbow and stub-up, unless specified differently in the contract drawings.
Conduit Bank Support: Conduit banks intended for both concrete encasement and direct burial should be rigidly supported to maintain horizontal and vertical spacing. This support should be achieved using Carlon Plastic “SNAP-LOC” spacers or their equivalent. These spacers should be placed at 1.5-meter (5-foot) intervals.
Spacer Sizing: Spacer sizing should match the conduit size and spacing requirements:

For 50 to 75 mm (2 to 3 inches) conduit, use spacers sized for 75 mm (3-inch) conduit with 50 mm (2-inch) horizontal and vertical separation.
For 88 to 127 mm (3 1/2 to 5 inches) conduit, use spacers sized for 127 mm (5-inch) conduit with 50 mm (2-inch) horizontal and vertical separation.

Transition Between Spacer Sizes: When both standard spacer sizes are used in large duct banks, transition from one size spacer in a lower horizontal row to the other size spacer in the next higher horizontal row. Invert a row of base spacers on top of the lower horizontal row to achieve this transition. The junction between base spacers should be solvent cemented and lashed to secure the higher horizontal rows from movement.

These guidelines ensure that RNC conduit installations are carried out properly, providing support, alignment, and spacing as necessary for the specific conduit sizes and configurations involved in the project. Proper installation helps maintain the integrity and safety of the conduit system.

5.2.2 Concrete Encased RNC Conduit

These sections provide detailed specifications for the installation of RNC (Rigid Nonmetallic Conduit) conduit banks in concrete-encased applications:

5.2.2.1 Conduit Banks in Concrete Encasement:

Conduit banks specified as “concrete encased” on contract drawings should use rigid RNC conduit.
The conduit banks should be encased in a concrete envelope with a minimum of 50 mm (2 inches) of concrete between conduits and a minimum of 75 mm (3 inches) of concrete between conduit and earth backfill.
The minimum depth below grade to the top of the concrete should be 600 mm (24 inches), unless otherwise indicated on the contract drawings.

5.2.2.2 Concrete Specifications:

The concrete used for conduit runs should have a strength mix of 13.8 MPa (2000 pounds per square inch).
The maximum size of the aggregate in the concrete should not exceed 9 mm (3/8 inch).
The slump of the concrete should be between 178 and 230 mm (7 and 9 inches) to ensure proper distribution around the ducts.
After pouring the concrete, red dye should be spread on the surface and worked evenly into the wet concrete.

5.2.2.3 Trench Preparation:

Before pouring the concrete envelope, the conduit trench should be thoroughly cleaned to remove all debris such as trash, paper, wood, or metal scraps.
Conduit should be rigidly supported to maintain spacing and anchored to prevent floating. This is achieved using Carlon Plastic “SNAP-LOC” spacers or equivalent spacers, placed at 1.5-meter (5-foot) intervals.
The bottom spacer should be supported by and anchored to the floor of the trench.

5.2.2.4 Concrete Placement:

When placing concrete around the ducts, the delivery chute should be adjusted to minimize the fall of concrete into the trench.
A splashboard should be used to divert the flow of concrete away from the trench sides and prevent dislodging of soil and stones.
Concrete encasement should be poured from one end of the duct section toward the other to accommodate conduit expansion or contraction as the concrete cures.

5.2.2.5 Use of Trench Walls:

Whenever possible, the walls of the trench should serve as forms for the concrete encasement.
The trench width should be no wider than necessary to provide the nominal side concrete thickness.

5.2.2.6 Backfilling:

After the concrete has set, the trench may be backfilled.
Backfill material for finishing the grading should be clean, structural fill.
Unacceptable backfill materials include cinders, coarse builder’s sand, highly organic soils (humus, peat), or highly plastic clays.
The backfill should be placed in uniform layers not exceeding 200 mm (8 inches) in depth and compacted to 95% of maximum density as established by ASTM D698.

5.2.2.7 Application to Ground Wires:

The backfilling requirements mentioned in paragraph 5.2.2.6 should also apply to trenches containing only buried ground wires.

These specifications ensure that the installation of RNC conduit in concrete-encased applications is carried out correctly, providing both protection and support for the conduit system while maintaining safety and integrity.

5.2.3 Direct Burial RNC Conduit

This section provides specifications for the direct burial of RNC (Rigid Nonmetallic Conduit) conduit banks:

5.2.3.1 Direct Burial RNC Conduit:

RNC conduit banks installed below grade, which are not specified to be “concrete encased,” should be direct buried using rigid, Schedule 40 conduit.
The minimum depth below grade to the top of the conduit should be 600 mm (24 inches), unless otherwise indicated on the contract drawings.

5.2.3.2 Minimum Separation and Clearance:

A minimum separation of 50 mm (2 inches), both vertically and horizontally, between ducts is required to allow for good backfill compaction and heat dissipation, unless otherwise indicated on the contract drawings.
A minimum clearance of 75 mm (3 inches) should be maintained between the trench bottom, trench walls, and ducts.
The trench should be graded true and free of stones and soft spots.

5.2.3.3 Conduit Support and Backfill:

Conduit banks should be rigidly supported to maintain vertical and horizontal spacing using Carlon Plastic “SNAP-LOC” spacers or equivalent, placed at 1.5-meter (5-foot) intervals.
The base spacer should be supported by the floor of the trench and, in areas with high water tables, anchored to the floor of the trench.
After completing duct bank construction, well-graded sand backfill should be placed dry to a depth of at least 200 mm (8 inches) over the top of the duct bank.
The backfill should be manually raked level and compacted to 90% of maximum density.
After compaction of the selected backfill, the remaining backfill to grade should be placed in uniform layers not exceeding 200 mm (8 inches) in depth and compacted. Care should be taken to avoid excessive tamping, which could lead to duct shifting or distortion.

5.2.3.4 Specifications for Initial Thermal Sand Backfill:

The material for the initial thermal sand backfill should be a well-graded sand that conforms to the requirements of a material classified as SW according to the Unified Soil Classification System.
Sieve analysis limits for this sand are provided for various sieve sizes.
The dry, compacted sand density should be approximately 1600 kg/m3 (100 pounds per cubic foot).
Two weeks after the contract award date, a standard sieve analysis should be performed on the sample by the contractor according to the procedures described in the American Foundrymen’s Society (AFS) Sand Testing Manual.

5.2.3.5 Final Backfill:

The backfill necessary to finish grade should be clean, structural fill.
Unacceptable materials for backfill include cinders, coarse builder’s sand, highly organic soils (humus, peat), or highly plastic clays.
The preferred final backfill is the well-graded sand used for the initial backfill.
The backfill should be placed in uniform layers not exceeding 200 mm (8 inches) in depth and compacted to 90% of maximum density as established by ASTM D698.

5.2.3.6 Warning Tape:

A red plastic warning tape reading “Caution – Buried Electric Line” should be installed at least 300 mm (12 inches) above each direct buried RNC conduit or conduit bank.
For conduit banks wider than 600 mm (24 inches), multiple warning tapes with parallel spacing of 600 mm (24 inches) should be used.

These specifications ensure the proper installation and protection of RNC conduit when direct buried, taking into account separation, clearance, support, and warning measures to maintain safety and integrity.

Sieve Size	Percent Passing
#4	75 to 100%
#10	50 to 65%
#16	30 to 50%
#30	25 to 35%
#50	10 to 25%
#100	5 to 15%
#200	0 to 5%

5.3 Metallic Conduit

5.3.1 Conduit Cutting and Burr Removal:

All metal conduit should be cut using a power hacksaw, band saw, or rotary pipe cutter.
After cutting, a (flute) reamer must be used on the interior of the conduit until all burrs are completely removed.

5.3.2 Metallic Lubricant Sealant:

All joints of galvanized steel and aluminum conduit must be coated with a metallic lubricant sealant.
Suggested sealants include “Lead Plate 250” as manufactured by Armite Laboratories or “Crouse-Hinds STL.”

5.3.3 Asphalt Paint Coating:

Steel conduit buried directly in soil and conduit stub-ups above grade should be coated with two coats of asphalt paint.
The minimum dry thickness of this coating should be 203 micrometers (8 mils).

5.3.4 PVC-Coated Conduit:

As an alternative to asphalt paint, factory-applied PVC-coated conduit may be used. This PVC coating serves as corrosion protection and eliminates the need for additional paint.

5.3.5 Steel Conduit for Direct Burial:

Steel conduit intended for direct burial should be installed following the guidelines outlined in section 5.2.3 (Direct Burial RNC Conduit).
However, the spacers in this case should be located at a maximum distance of 4.2 meters (14 feet) apart.

These specifications provide details on how to cut and prepare metal conduit, the use of lubricant sealants, options for corrosion protection, and installation guidelines for steel conduit in direct burial applications. Proper preparation and protection are essential to ensure the integrity and longevity of metal conduit installations.

6. DIRECT BURIED CABLE

6.1 General

6.1 General Guidelines for Underground Cables:

6.1.1 Cable Types:

All cable types must align with the specifications outlined in the contract drawings.
Refer to the testing requirements outlined in Section 7 before backfilling trenches.

6.1.2 Continuous Cable Runs:

Underground cable runs must be continuous without splices.
Splicing of cables below grade is generally prohibited, unless explicitly shown on contract drawings or authorized by Air Products Electrical Design.

6.1.3 Minimum Cable Depth:

The minimum depth from the surface to the top of the cable must be 600 mm (24 inches), unless otherwise specified in the contract drawings.
Trenching, backfill, and warning tape requirements should follow the guidelines provided in Section 5.2.3 (Direct Burial RNC Conduit).

6.1.4 Cable-Pipe Spacing:

Direct burial cables should be spaced at least 600 mm (24 inches) away from underground pipes, whether they cross or follow parallel routes.
When cables and pipes intersect, the cables should generally be buried at a minimum depth of 760 mm (30 inches) below the surface. If it’s not possible to maintain this minimum depth, the cables should be routed under the pipes.
Any conflicts between these requirements and the contract drawings should be promptly brought to the attention of an Air Products field representative.

These guidelines specify the cable types, continuity, minimum depth, and spacing requirements for underground cables. Proper adherence to these specifications ensures the safe and effective installation of underground cables.

6.2 Cable Mechanical Protection

6.2 Protection and Installation of Underground Cables:

6.2.1 Riser Cable Protection:

Riser cables must be protected using rigid galvanized steel conduit that is securely fastened in place.

6.2.2 Protection near Obstructions:

Direct burial cables passing close to obstructions such as foundations should be cushioned. This is achieved by placing thermally compatible bags filled with sand or other suitable barrier material between the cable and the obstruction.

6.2.3 Avoiding Foundations:

Direct buried cables should be routed to avoid foundations. Cables must never be directly buried beneath or within a foundation or floor slab.
When cables must penetrate a foundation or floor slab, underground conduit sleeves should be installed from the point of penetration to a location 1500 mm (5 ft) beyond the edge of the foundation or floor slab.

6.2.4 Warning Tape:

A red plastic warning tape with the text “Caution – Buried Electric Line” must be installed at least 300 mm (12 in) above each direct buried cable or cable bank. This warning tape should run continuously for the entire length of the installation.
Cable banks wider than 600 mm (24 in) should have multiple warning tapes with parallel spacing of 600 mm (24 in).

6.2.5 Termination in Concrete Slabs:

When direct burial cables terminate within concrete slabs, conduit sleeves should be provided to facilitate cable installation.
Contractors should refer to the contract drawings for specific details regarding the installation of conduit sleeves.

6.2.5.1 Installation Timing for Cable in Conduit Sleeves:

Direct burial cable should not be inserted into conduit sleeves (as mentioned in paragraph 6.2.5) until electrical building construction or installation is complete, and electrical equipment has been set in place.
During this phase, cable should be left on the reel and protected as directed by an Air Products field representative.

These guidelines address the protection and installation of underground cables, ensuring their safety and functionality when passing near obstructions, foundations, or concrete slabs. The use of warning tape is also emphasized for safety and identification purposes.

6.3 Medium Voltage Direct Buried Cable (Over 600v)

6.3 Medium Voltage Cable Installation Requirements:

6.3.1 Additional Requirements for Medium Voltage Cable:

All requirements mentioned in Section 6 apply to medium voltage cable installations, with the following additional requirements outlined below.

6.3.2 Cable Groupings and Burial Depth for Three-Phase Circuits:

For medium voltage cables in a three-phase circuit, the following criteria for cable arrangement must be followed:
Three single conductors should be grouped closely together in a parallel spacing arrangement, meaning there should be no separation between phases.
Multiple circuits should be separated by a minimum of 600 mm (24 in) of backfill and buried at a minimum depth of 760 mm (30 in) below grade. Contractors should refer to STD-P320A for detailed specifications regarding this arrangement.

6.3.3 Concrete Slab above Cable:

A concrete slab, 50 mm (2 in) thick, should be placed in the trench above the medium voltage cable. This slab should extend at least 150 mm (6 in) beyond either side of the span of the underground cable.

6.3.4 Concrete Slab for Routing above Existing Underground Facilities:

When medium voltage direct burial cables are routed above existing underground facilities, a 50 mm (2 in) thick concrete slab must be placed in the floor of the cable trench in the area of the crossing. This slab should extend at least 150 mm (6 in) in all directions beyond the span of the cables.

6.3.5 Surface Marker Posts and Identification Plates:

All medium voltage direct buried cables must have concrete surface marker posts placed along their routes. These posts should be fitted with permanent, non-corrodible metal warning and identification plates inscribed with the text “DANGER ELECTRIC CABLES.”
Surface marker posts should be installed at all points where cable routes change direction, at splices, and at maximum intervals of 15.0 m (50 ft) along straight sections of cable routes.

6.3.6 Cable Acceptance and Testing Requirements:

Refer to specification 4AEL-620303 for cable acceptance and testing requirements that must be completed before installation of medium voltage direct buried cables.

These additional requirements are specific to the installation of medium voltage cables and are essential for ensuring safety and proper functioning of the cables in underground installations. The use of concrete slabs and surface marker posts with warning and identification plates helps enhance safety and visibility. Testing requirements are also highlighted for compliance before installation.

INSPECTION AND TESTING

7.1 Inspections

7.1 Inspections and Testing Requirements:

7.1.1 Notice for Inspections:

Contractors are required to provide a minimum of 24 hours notice to the Air Products field representative before conducting any necessary inspections or testing.

7.1.2 Inspection of Conduit Duct Banks and Grounding Systems:

Before any backfilling work commences, all conduit duct banks and grounding systems must undergo inspection and approval by the Air Products field representative.

7.1.3 Inspection of Grounding Electrode System Installation:

During the installation of the grounding electrode system, both the contractor and the Air Products field representative should visually inspect the installation. This inspection aims to ensure that all grounding electrode system components have been correctly provided and that all system connections have been made in accordance with the contract drawings.

7.1.4 Inspection and Testing of Ground System Splices and Connections:

Ground system splices and connections should be visually inspected to verify that proper welding or compression has been carried out. Additionally, these connections must be tested for electrical continuity as specified in paragraph 7.3.1. Exothermic connections should undergo a strength test by being struck with a 1-pound hammer.

7.1.5 Inspection of Grounding Electrode System After Backfilling:

Following the completion of backfilling in the grounding electrode system trenches, both the contractor and the Air Products field representative should perform a visual inspection of the installation. This inspection ensures that all grounding electrode system pigtails, as indicated on the contract drawings for future use, have been provided. Refer to paragraph 5.1.5 for conduit verification and completion requirements.

These inspection and testing requirements are crucial to verify that the installed systems and components meet the specified standards and comply with the contract drawings. They help ensure the integrity and safety of the electrical installations.

7.2 Testing

7.2.1 Testing Requirements and Codes:

In this section, the testing requirements are outlined, and they are accompanied by specific codes indicating various aspects of these tests. Here’s an explanation of each code:

Test Required A: This code signifies that the test reports must be documented in duplicate. Copies of these reports need to be submitted to Air Products on a daily basis. The originals of these reports should be organized into a comprehensive indexed test report, which is to be submitted to Air Products upon the completion of the job. It is essential that all documentation includes the full load test current for each phase, along with other necessary test data.
Test Required B: Tests with this code must be witnessed by a qualified Air Products field representative who possesses a technical understanding of the tests being conducted and the test equipment being used. This representative will oversee and verify the accuracy and integrity of the tests.
Test Required C: Tests marked with this code should be carried out by a reputable and qualified specialized testing service. This service must be approved by both the Air Products field representative and, where applicable, the inspection agency with jurisdiction over the project. This ensures that the testing is conducted by professionals with the necessary expertise.
Test Required D: For tests requiring this code, the test equipment used must be properly calibrated and certified. Calibration must adhere to the specified calibration requirements outlined in section 600.001. Evidence of calibration, in documented form, should be provided to the Air Products representative. This documentation should include details such as the identification of the equipment being calibrated, reference to the calibration procedure used, the equipment utilized for calibration, the method for checking calibration, the date of calibration, the individual responsible for performing the calibration, and the calibration due date.

These codes and requirements are in place to ensure that all testing procedures are conducted accurately, documented comprehensively, and overseen by qualified individuals or services to meet the necessary standards and regulations.

	Test Required
7.3 Grounding Electrode Testing

7.3.1 Perform a contact resistance test on each connection or splice using a digital low resistance ohmmeter (ductor). Resistance test values shall be 30 micro-ohms per joint, or less. A fluke meter capable of reading less than 1 ohm is acceptable with approval.		B

7.3.2 Contractor shall measure the grounding electrode system resistance by the three-point “fall-of-potential” method with the Biddle ground tester on a dry day according to the latest edition of IEEE Standard 81. The measured resistance of the grounding electrode system must be 5.0 ohms or less. Ground rods or electrodes shall be tested before connected to the grounding grid system. All test wells shall be tested. Test data to be recorded on Form 2.		A,B,D

	Test Required
7.3.2.1 A minimum of two separate resistance readings shall be measured. One reading shall be measured using the grounding test well at the electrical building/substation area. The other reading shall be measured using a test well, grounding electrode system conductor, or pigtail located the farthest distance away from the Electrical Building test well location on the site. Any discrepancies in the readings shall be brought to the attention of the Air Products Global Support Services (GSS) Electrical Engineering.	A,B,D

7.4 Low Voltage Cable Testing

7.4.1 Perform dc insulation resistance test on all direct-buried underground feeders before backfilling trenches. Record test data on Form 1.	A, D

7.4.2 Perform dc insulation resistance test on all direct -buried underground feeders after backfilling trenches. Record test data on Form 1.	A, D

7.5 Medium Voltage Cable Testing

7.5.1 Perform acceptance testing per specification 4AEL-620303 Sections 4 and 7.	A,B,C,D

7.5.2 Perform dc insulation resistance test on all direct-buried underground feeders after backfilling trenches.	A, D

7.6 Documentation
7.6.1 File one copy of the completed documentation on-site for future reference and forward one copy to the Air Products field representative.	A, D

Insulation Resistance Test Values for Electrical Apparatus and Systems

From NETA ATS-2007 (Table 100.1)

Nominal Rating of Equipment in Volts	Minimum Test Voltage, DC	Recommended Minimum Insulation Resistance in Megohms
250	500	25
600	1,000	100
1,000	1,000	100
2,500	1,000	500
5,000	2,500	1,000
8,000	2,500	2,000
15,000	2,500	5,000
25,000	5,000	20,000
34,500 and above	15,000	100,000

Test results are dependent on the temperature of the insulating material and the humidity of the surrounding environment at the time of the test.

Form 1

	INSULATION RESISTANCE TEST RESULTS
Project Name:	Project Number:		Contractor P.O. #:
Contractor Name:	Test Voltage, Vdc:		Circuit/Cable #:
Cable Mfr.:	Cable Length, Feet:		Aerial, Duct, or U/G:
# of Conductors per Cable:	Wire Size, AWG or MCM:		Shielded or Non-shielded:
Voltage Rating of Cable:	Insulation Type:		Insulation Thickness:
Pothead or Terminal Type:	Location, Indoor or Outdoor:		Date:
Time:	Temperature, °C/°F-% R.H.:		Weather:
Operator Name:	Operator Company:		Test Set Mfr.:
Model #:	Serial #:		Calibration Date:
Corona Suppression (Ionization Protection) Used, Yes/No:		Type Used:
Test Set Guard Lead Used During Test, Yes/No:		Where Connected:
Contacts/Cable Cleaned Before Test, Yes/No		Cleaner Type:
List Associated Equip. Used:
Remarks:

TEST DATA – MEGOHMS

	Æ A- Gnd	Æ B- Gnd	Æ C- Gnd	Æ A- Æ B	Æ B- Æ C	Æ C- Æ A
1/4 Min.
1/2 Min.
3/4 Min.
1 Min.
2 Min.
3 Min.
4 Min.
5 Min.
6 Min.
7 Min.
8 Min.
9 Min.
10 Min.
10/1 Min. Ratio (PI)

_________________________________		_______________________________
Contractor Superintendent/Date		Air Products Representative/Date

Click on Insulation Resistance Test Results (above)

for Excel Worksheet

Form 2

Grounding System Resistance Test Report

Date:___________

Facility:_________________________________________ Equipment Location: _________________________________________ Project #:____________________________

Equipment Designation/Tag #:__________________________________________________ Unit #:____________________________ of ____________________________ Units

Manufacturer:_______________________________________________________________ Serial number:_________________________________________________________

Model number:______________________________________________________________ Type:________________________________________________________________

Equipment Rating:___________________________________________________________ Volts:_______________________________ Amps:__________________________

Technician:_________________________________________________________________ Test Set:____________________________ Sheet #____________ of ___________

Season __________________ Type Soil ____________ Soil Condition Dry _____________ Temperature ____________________°F

Moist____________ Humidity ______________%

Single Rod Multiple Rods _______________ Buried Strips or Wire ___________

Type System Depth _________Ft. Longest Dimension ___________Ft. Longest Dimension ____________Ft,

Distance to Aux Current Electrode _______________Ft.

Purpose

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