S02 NGrid Installation Specifications.pdf

Supplement to Specifications for Electrical Installations

Underground Commercial Distribution (UCD) Installation and Responsibility Guide

Electric System Bulletin No. 759B July 2010

(Supersedes all previous versions of ESB 759)

For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

Supplement to Specifications for Electrical Installations

Underground Commercial Distribution (UCD) Installation and Responsibility Guide

Electric System Bulletin No. 759B July 2010

(Supersedes all previous versions of ESB 759)

For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

National Grid / Supplement to Specifications for Electrical Installations / ESB 759B July 2010

TABLE OF CONTENTS

UCD Specifications and Installation Guide Acknowledgement (Job Spec/Signoff Forms)

1.0 Scope

2.0 General Requirements

3.0 Type of Service…...…………

4.0 Plans…...…………..…

5.0 Permits…...….…………

6.0 Easements

7.0 Responsibility and Ownership

8.0 Transformer Clearance From a Building

9.0 Transformer Clearance From Objects……………………………………………………

10.0 Transformer Accessibility

11.0 Transformer Mechanical Protection/Bollards

12.0 Transformer Pad

13.0 Transformer Secondary

13.1 Transformer Secondary Connections

13.2 Secondary Bolt Assembly

13.3 Secondary Splice Box…...…………

14.0 Transformer Sweep Entry

15.0 Transformer Grounding and Bonding

16.0 Oil Containment

17.0 Riser Pole…...…………

18.0 Heavy Duty Handhole

19.0 Primary Cable Pull/Splice Box

20.0 Trench Requirements

20.1 Trench Depth New York/New England Concrete Encased Conduit

20.2 Trench Depth Conduit Direct Buried New York (under certain circumstances agreeable with the Company)

20.3 Trench Depth Direct Buried New York

Figure 20.0-1 Typical Trenches

21.0 Conduit Requirements

21.1 Pulling Tape

21.2 Trench and Conduit System Inspection…...…………

For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

22.0 Primary Cable and Electrical Equipment…...…………

23.0 Secondary Cable and Conduit System…...…………

24.0 Metering…...…………

25.0 Manhole…...…………

25.1 Manhole Frame, Ring and Cover…...…………

25.2 Switchgear Manhole…...…………

25.3 Switchgear Manhole Ground Grid…...…………

25.4 Switch Gear Manhole Bollard Layout…...…………

26.0 Fiberglass Switchgear Base with Conduit Entry’s…...…………

26.1 Fiberglass Switchgear Ground Grid…...…………

26.2 Switch Gear Fiberglass Boxpad Bollard Layout

27.0 Transformer Pad Specifications…...…………

Figure 27.0-1 15kV Transformer Pad 75- 500kVA 44-113

Figure 27.0-2 15kV Transformer Pad 750- 2500kVA 44-114

Figure 27.0-3 25-35kV Transformer Pad 75- 300kVA 44-115

Figure 27.0-4 25-35kV Transformer Pad 500-2500kVA 44-116

28.0 Sample Installations …...…………

29.0 Bollard Detail

30.0 Concrete Specifications…………………………………………………

31.0 Easement Applications……………………………………………

31.1 New England Easement Application Form……………………………………………

31.2 New York Easement Application Form……………………………………………

32.0 Concrete Approved Precast Manufacturers……………………………………………

33.0 Approved Materials – Underground Commercial Installations……………………………………… 54

34.0 Other Materials/Suppliers……………………………………………

35.0 Job Check off Sheets……………………………………………

35.1 3 Phase UCD Direct Burial Inspection Check List New York……………………………………… …57

35.2 3 Phase, Conduit Encased in Concrete Inspection Check List…………………..………

35.3 3 Phase UCD Conduit Inspection Check List New York

35.4 Transformer Foundation Inspection Check List

36.0 Cable Installation Maximum Pull Chart

37.0 Padmount Compartment Sealing Requirement

38.0 Revision History

1For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

Design and Layout

Pad Inspection NE

Trench Inspection

Company Installation

Eight weeks

One day

3 days

4 weeks

Company receives all required plans, load data and easement information

Company inspector

Company inspector

After all inspections are approved and permits/easements are procured.

Lead-Time Notes

NOTE: The above times are estimates only.

Project Title________________________________________________________________________

Location__________________________________________________________________________

Owner/Developer___________________________________________________________________

Customer’s Representative _____________________________ Date_______________________

Company Representative_______________________________ Date______________________

Specifications Issued___________________________________ Date_______________________

Company’s Copy

National Grid / Supplement to Specifications for Electrical Installations / ESB 759B July 2010

URD Specifications and Installation Guide Acknowledgement (Job Spec/Signoff Forms)

The requirements and specifications outlined in this guide book must be strictly followed. Any requirements not adhered to can pose safety problems, can be detrimental to the installed system and must be corrected before final acceptance. The customer will bear full cost to make corrections to sub-standard installations.

Customer is responsible to provide enough lead time for the company to design job, provide inspections and install company equipment where applicable.

Typical lead times are shown below.

2 For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

3For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

UCD Specifications and Installation Guide Acknowledgement The requirements and specifications outlined in this guide book must be strictly followed. Any requirements not adhered to can pose safety problems, can be detrimental to the installed system and must be corrected before final acceptance. The customer will bear full cost to make corrections to sub-standard installations.

Customer is responsible to provide enough lead time for the company to design job, provide inspections and install company equipment where applicable.

Typical lead times are shown below Design and Layout.

Design and Layout

Pad Inspection NE

Trench Inspection

Company Installation)

Eight weeks

One day

Three days

4 weeks

Company receives all required plans, load data, and easement information

Company inspector

Company inspector

After all inspections are approved and permits/easements are procured.

Lead-Time Notes

NOTE: The above times are estimates only.

Project Title________________________________________________________________________

Location__________________________________________________________________________

Owner/Developer___________________________________________________________________

Customer’s Representative _____________________________ Date_______________________

Company Representative_______________________________ Date______________________

Specifications Issued___________________________________ Date______________________

Customer’s Copy

4 For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

5For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

1.0 Scope

The purpose of this specification is to define, interpret and clarify the scope of work and material dealing with services to padmounted transformers and is a Supplement to Electric SYstem Bulletin (ESB) 750).

This specification does not cover any primary metering.

It is important that the Specifications for Electrical Installations book (ESB 750) be obtained and referred to in conjunction with this supplement for these installations. Any reference in this specification to the Company shall mean the nationalgrid Company. Any reference to the Customer shall mean the Contractor, Developer or property owner.

2.0 General Requirements

All electrical wiring to be connected to the Company equipment shall be installed in accordance with one or all of the following:

Local Municipal Inspection Authority

State’s Electrical Code

National Electrical Code

National Electrical Safety Code

Applicable Distribution Construction Standards of the Company

National Grid’s Specifications for Electrical Installations

There shall be no attempt to deviate from either the Distribution Standards of the company or the Company construction plan without the approval of the Company. Any specifications noted shall supersede the Specifications for Electrical Installations booklet unless otherwise approved by the Company.

Often a pre-construction meeting is helpful to all parties to ensure timely completion of the project.

The Company Business Service Representative will make the necessary arrangements for a pre-construction meeting, or a meeting to discuss changes. Company representatives will be available to discuss construction problems when requested or during a field visit

References:

ESB 750 - Specifications for Electrical Installations

ESB 754 - Outdoor Padmounted or Vault Enclosed Three Phase Transformer

All ESB’s are available at http://www.nationalgridus.com/electricalspecifications

The Customer shall be responsible to have all electrical and physical design documents prepared and updated by a design professional, in accordance with Section 1.7 of ESB 750 for the trenching, conduit, transformer pad, and handhole installations.

3.0 Type of Service

Electric service shall be three phase, four wire, 208Y/120 volts or 480Y/277 volt supplied from a padmount transformer to be located on the Customer’s premises. The primary electrical service to the padmounted transformer will be supplied from a pole or cable system owned by the Company, except in New Hampshire. In New Hampshire, the primary service to the transformer shall be customer owned.

6 For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

4.0 Plans

When municipal approval is required, the Company shall receive final town approved development plans on a scale not less than one-inch equal to one hundred feet prior to engineering construction plans. The property site plan shall show all proposed and existing utilities, i.e. water, gas, sewer, cable television, telephone, etc.

Direct Burial Systems in general: the Company specifies an arrangement whereby the Company’s power cables may run parallel with communication and other power cables, but not parallel with other utilities e.g. water, gas, sewer. These utilities shall be in a separate trench. The other utilities must maintain clearances as outlined in the NESC or by mutual agreement. Nationalgrid gas is permitted in the same trench with the following requirements: gas shall be at a minimum depth of 18” and shall maintain a minimum separation of 12” between all other utilities.

Conduit Systems in general: the Company requires a spare conduit for all Company owned duct systems, as shown in Company plans. The Company duct system when required must be in a separate concrete envelope from all other utilities. Other utilities must maintain clearances as outlined in the NESC.

5.0 Permits

In general, all applicable permits necessary to trench and excavate, including street openings and wetland permits, shall be obtained by the Customer and made available upon request if necessary.

The Customer shall be responsible for including these padmount and conduit/trench specifications with the wetlands application for developments located in or near wetlands. A copy of the wetlands permit may be requested by the Company prior to acceptance of the conduit/trench system by the Company.

The excavator doing the excavation shall obtain the required DIGSAFE permits before any excavation may take place in a public way. The Customer/Company doing the excavation is urged to obtain copies of the applicable statute and become familiar with its requirements. Similarly, the Customer/ Company shall determine if the municipality in which the excavation is to be done requires that water, sewer or other utility, municipal or private, be contacted separately.

The Customer shall certify to the Company that areas in which the Company is to perform installation or maintenance work is free of preexisting contamination by hazardous wastes or materials and to indemnify the Company for any claims, costs, expensed, suits, demands, citations, fines or damages of any kind arising from the presence of any such contamination.

6.0 Easements

As a condition of service, the Applicant or Customer must provide the Company with an easement(s), properly executed by all owners of record drafted by the Company, for all Company owned facilities located on private property (to include User or Private Roads (NY) and Private Ways (MA, NH, RI)), whether or not such private property is owned by the Customer. The Applicant or Customer will provide such easement(s) prior to the start of the Company’s construction and at no cost to the Company. The Applicant or Customer shall provide a copy of its mortgage and deed, together with a copy of the survey and/or plan of record, for the Company’s use in preparation of the easement(s) as well as any other documents necessary for the Company to prepare such easement(s).

Rights-of-Way, Easements In UCD, URD, or multiple occupancy building applications, the Customer shall provide the Company with two copies of the approved development map, certified as final by a design professional or licensed land surveyor, which the plan shall have been recorded or filed with the Registry of Deeds. The map shall indicate lot lines, building setback lines, grade lines, sidewalk, roadway, sewer, water, drainage, and

7For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

other facilities. The map shall also include the identification and, where appropriate, delineation of sensitive environmental resources including, but not limited to, wetlands, streams, archaeologically sensitive areas, and hazardous waste disposal areas, etc. In addition to this base information, this map shall clearly indicate the easement strips dedicated to the Company and the location of the lots (units) for which electric service is requested. The governmental authority having control over land use shall approve this map. In addition, when electronic maps are used, the Customer must consult the Company for submittal.

Rights-of-way and easements must be cleared of any obstructions at no charge to the Company.

The applicant shall grade the right-of-way or easement to within six inches (150 mm) of final grade before the Company commences construction. The applicant must maintain the Company’s clearance and grading requirements.

Easement application forms are located on pages 49 and 51.

7.0 Responsibility and Ownership

The division of ownership and responsibility shall be as outlined below by state. Typical installation specifications to reflect installation practices are shown in the back of this guide.

Massachusetts and Rhode Island

The Company will:

Supply, install, own and maintain:

primary cable, CT and PT’s, Transformer and Meter.

*Note: company will not install CT’s in CT cabinet.

Check the final torque connections to the transformer’s secondary bushings.

Own and maintain:

Primary conduit system (installed by Customer).

Secondary cable installed by the customer from transformer to secondary splice box, where required.

The Customer will:

Install, own and maintain:

transformer pad, reinforcement and grounding, oil containment where required by the Company or local authority, transformer mechanical protection, secondary equipment (including a secondary splice box if required), connect secondary connectors for the transformer, self contained meter box where required by the Company.

Supply and install to Company’s specification:

all primary conduits including concrete encasement, steel riser including 90 degree sweep and bonding clamp with tap, secondary cable from transformer to splice box if required.

make up secondary cable ends, including final toque of the secondary cable to the transformer.

Note: The Customer will be held accountable for any transformer damage occurring due to improper secondary installation.

8 For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

New Hampshire

The Company will:

Supply, install, own and maintain:

Transformer

CT and PT’s and

Meter

* Note: company will not install CT’s in CT cabinet.

Check the final torque connections to the transformer’s secondary bushings.

Own and maintain:

Secondary cable installed by the customer from transformer to splice box where required.

The Customer will:

Install, own and maintain:

Primary cable and conduit system, transformer pad, reinforcement and grounding, oil containment where required by the Company or local authority, transformer mechanical protection, steel riser including 90 degree sweep and bonding clamp with tap.

all secondary equipment (including a secondary splice box if required), connect secondary connectors for the transformer, self contained meter box where required by the Company.

Supply and install to Company’s specification:

secondary cable from transformer to splice box if required.

make up secondary cable ends, including final toque of the secondary cable to the transformer.

Note: The Customer will be held accountable for any transformer damage occurring

9For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

New York

The Company will:

Supply, install, own and maintain:

primary cable, transformer and

Meter.

Supply and maintain

CT and PT’s

Check the final torque connections to the transformer’s secondary bushings.

The Customer will

Install, own and maintain:

primary conduit and concrete encasement when required, transformer pad, reinforcement and grounding, oil containment where required by the Company or local authority, transformer mechanical protection, all secondary equipment (including a secondary splice box if required), connect secondary connectors for the transformer, self contained meter box where required by the Company, steel riser including 90 degree sweep and bonding clamp with tap.

Supply to Company’s specification when required:

open trench

Install to Company’s specification when required:

CT’s and PT’s make up secondary cable ends, including final toque of the secondary cable to the transformer.

Note: The Customer will be held accountable for any transformer damage occurring

10 For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

8.0 Transformer Clearance From a Building

Oil insulated equipment shall be located in compliance with the minimum clearances indicated below. For existing buildings, the transformer shall not block access to existing building systems, such as wall mounted fire sprinkler systems. The building owner’s and/or tenants fire insurance carrier or local inspection authority may restrict the proximity of the equipment to doors, windows or combustible materials. It is the customer/developer’s responsibility to determine the acceptability of the proposed location of the equipment.

Notes:

1. Noncombustible material is defined as a material that will not ignite, burn, support combustion or release flammable vapors, when subjected to fire or heat, or as described by the latest edition of the NFPA-220.

2. No portion of a building or building structure shall overhang any part of the pad-mounted equipment.

3. In cases where required distances cannot be met, a noncombustible barrier, 6 foot minimum height, shall be constructed. This barrier shall be designed to provide adequate fire protection to the existing structure. A design for this structure shall be prepared and sealed by the customer’s Professional Engineer or Registered Architect and shall further be approved by the local authority having jurisdiction of building code enforcement.

4. For exits from a public assembly room, such as an auditorium, a 10 foot minimum clearance should be increased to 25 feet, unless there is a barrier.

5. This requirement may vary between individual states. Refer to the building code regulations for the state involved.

National Grid / Supplement to Specifications for Electrical Installations / ESB 759B July 2010

Legend

Equipment, oil insulated

Window

Door

Ventilating Duct

11For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

9.0 Transformer Clearance From Objects

Clearances from objects:

A. An area measuring 10 feet from any point of the transformer pad shall be kept free of all:

buried water lines, storm drainage lines, gas lines, other electric lines;

underground fuel storage tanks; and above grade fire hydrants, cell towers, self contained diesel or diesel byproduct fueled generators, and outdoor enclosed generators.

Note: The 10 ft. clearance may be reduced with a noncombustible barrier (see Note 3) and shall not be less than five (5) feet from the edge of the transformer pad. The Customer or their authorized representative shall obtain this clearance reduction approval from the Company and the local AHJ(Authority Having Jurisdiction), as necessary, prior to the noncombustible barrier installation.

B. An area measuring 25 feet from any point of the transformer pad shall be kept free of all:

exposed water lines, gas piping, sewer lines;

open conductor electric lines; and above grade gas meters or regulator vents, fuel storage tanks or dispensing units, and non-enclosed gasoline/ propane / LP or LNG gas fueled generators.

chemical storage silos / tanks.

Note: The 25 ft. clearance may be reduced to 10 ft. with a noncombustible barrier (see Note 3) and shall not be less than five (5) feet from the edge of the transformer pad.

The Customer or their authorized representative shall obtain this clearance reduction approval from the Company and the local AHJ(Authority Having Jurisdiction), as necessary, prior to the noncombustible barrier installation.

10.0 Transformer Accessibility

Equipment shall be located within 10 feet of a way open to vehicular traffic and a minimum distance from any structure such as poles, fences, etc. as a means to permit accessibility for installation and maintenance. A minimum of 10 feet of clear space shall be maintained in front of the equipment doors to permit installation and removal of separable connectors and fuses with shotgun stick.

For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

11.0 Transformer Mechanical Protection/Bollards

Whenever possible, equipment should be located so it is not subject to vehicular damage. If this is not feasible, adequate guards such as concrete filled pipes (Bollards) shall be placed to protect the equipment.

Bollards shall consist of 6 inch minimum diameter hot dip galvanized or painted steel pipes filled with concrete. When Bollards can not be painted at the time of installation, painted covers shall be installed. Page 56 shows manufacturer. Bollards are to be 5 feet above the ground and a minimum of 4 feet below the ground. Bollards to be set in a concrete footing as shown in detail below. Concrete is to be crowned on top of all bollards. Bollards shall be installed with due care to avoid interfering with ground grid and conduits. Refer to Pages 37 thru 40 for Transformer Pad dimensions. For switchgear locations, see pages 34 and 35.

The number, type (galvanized or steel) and locations of bollards shall be determined by Distribution Design/Planning, taking into account proximity to traffic and to buildings as well as other barriers to traffic. Other factors such as salt spray and fertilizers may impact type of bollard required.

Suggested bollard locations and dimensions are shown below. The location of bollards shall not impede a door opening of 100 degrees.

Notes:

1. Six foot minimum clearance from front of pad.

2. Distribution Design/Planning shall designate the number and location of Bollards by marking the Bollards of this drawing as follows:

3. Bollards shall be supported with a 12” minimum diameter concrete footing 6” below grade to base of the bollard.

4. For installations around oil containment curbs, install bollards six feet minimum on all applicable sides.

Picture of Bollard cover, use for when Bollards can not be painted.

Bollards Required

Bollards Not Required x

Blow up drawing detailing this is located on page 44

13For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

12.0 Transformer pad

The Customer shall provide and install a concrete transformer foundation in accordance with the Company standards. Precast concrete transformer foundations built to Company standards are available from a variety of vendors listed on page 53. Spec sheets of the different size pads are shown on pages 37 thru 40.

Cast in place pads shall meet the following specifications. Concrete shall be a Mix M-4 detailed specifications are on pages 45 thru 48. Reinforcing in pad shall be # 5 grade 60 bars and shall conform to ASTM STANDARD A 615 of latest date. Reinforcing rods are to be located in center of the slab, with a minimum of 2 inches of clearance from face of concrete. All transformer pads must have and adequate base of 2 inches of sand and 12 inches of gravel as shown on pages 37 thru

40. The gravel shall be thoroughly compacted and the sand thoroughly wetted immediately before placing the concrete.

Massachusetts, New Hampshire and Rhode Island

The location of the concrete transformer pad, on the Customer premises, shall be approved by the Company in advance of the construction. The Company must, with sufficient notification (24 hours minimum) from the Customer, inspect the forming and reinforcing of the pad, the sub grade preparation, and the ground grid prior to the pouring of concrete. This requirement is critical. Failure to have inspection done may result in the need to remove and rebuild the concrete foundation

New York

The location of the concrete transformer pad, on the Customer premises, shall be approved by the Company in advance of the construction.

13.0 Transformer Secondary

Size and number of secondary cables shall be in accordance with the NEC and shall be approved by the electrical inspector or AHJ of the town or city involved. Maximum number of secondary cables to be physically connected to the Company's pad-mounted transformer is outlined below:

4 Hole Spades 6 sets 750 kcmil Max.

6 Hole Spades 8 sets 750 kcmil Max.

10 Hole Spades 10 sets 600 kcmil or 8 sets of 750 kcmil

Secondary cable requirements greater than this, will require a separate compartment, handhole, or bus duct.

Secondary cable shall not be installed until pad mount transformer has been set to ensure adequate length of secondary cable and connections.

All acceptable spade terminals are shown in Figures 1, 2 and 3. Minimum terminal thickness is to be ¼ inch, with 9/16 inch holes.

14 For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

Notes:

1. Figure 4 – Compression connections will accommodate up to four cables with a maximum individual lug width of 1¼ inch.

2. Figure 5 – Compression connections will accommodate two cables with lug greater than 1¾ inch width.

3. Figure 6 – Typical example of bolted connections for two, four or six cables to maximum capacity of lug.

4. Metering (CT’s) mounted inside the padmounted transformer may reduce the number of sets of secondary that can be installed by blocking off some holes on the secondary spade. In some cases the customer may be required to purchase a secondary splice box.

5. A list of a few manufacturers that supply the connectors is located on page 56.

Figure 1 Figure 2 Figure 3 kVA Rating L.V. Rating kVA Rating L.V. Rating kVA Rating L.V. Rating 75 – 300 208Y/120 500 208Y/120 750 – 1000 208Y/120 75 – 500 480Y/277 750 – 1500 480Y/277 2000 – 2500 480Y/277

Figure 4 Figure 5 Figure 6 4 Cables – 500 kcmil & Below

15 For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

13.1 Transformer Secondary Connections

All connectors and connector fasteners shall be furnished, installed, owned and maintained by the customer/developer. Connectors shall be approved by the Company prior to purchase.

Final electrical connection to the transformer secondary terminals shall be inspected by the Company. The customer/developer shall make all final connections to the spades of the pad-mount transformer to a final torque of 40 foot pounds. Size and number of secondary cables shall be in accordance with the NEC and shall be approved by the electrical inspector or AHJ for the town or city involved.

13.2 Secondary Bolt Assembly

The customer/developer shall supply and install aluminum connectors for use with aluminum cable or copper connectors for use with copper cable. Tin plated connectors can also be used as an alternate connector for aluminum and copper connectors. Connector shall be a cable to flat clamp or compression type connector, with a minimum of two holes in the flat pad and two clamping elements or two compressions per cable, and must be approved by company representative. Bolts and flat washers shall be grade 304 stainless steel. Belleville washers shall be grade 301 stainless steel. Nuts shall be waxed grade 316 stainless steel.

A. A flat washer is placed between the concave side of the belleville washer and the surface of the member being joined. The belleville is thus captured between the head of the bolt and the large flat washer. The flat washer should have an outside diameter greater than the flattened belleville’s such that no overhand results. Select a flat washer that is twice as thick as the belleville for strength. (If not available, stack two or three thinner washers to achieve the same effect).

B. With the belleville washer captured between the flat washer and the bolt head, fit the assembly into its hole. When the washers are fitted in position, there should be no interference with washers of adjacent bolts and no overhang over surface edges.

C. Tighten the nut on the bolt (with a washer of its own) until a sudden, noticeable increase in torque is required to continue. The belleville washer is now flat. It is not necessary to “back off” the nut after tightening to this point.

16 For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

13.3 Secondary Splice Box

A secondary splice box may be required where the customer’s number of secondary cables exceeds the maximum allowed amount on the transformer. Supplying and installing this box is the customer’s responsibility. The cables from the transformer to this box are to be specified by company’s representative. The customer is responsible to supply and install the cables.

Once the service is energized the company will take over ownership of only the secondary cables from the transformer to the secondary splice box.

A list of a few manufacturers that supply the secondary splice box is located on page 56.

14.0 Transformer Sweep Entry

Conduit shall be installed as shown on Pages 37 thru 40 before slab is poured. Use 36 inch radius sweeps, with couplings, nipples and bushings as required. Sweeps for primary cables shall be galvanized steel or schedule 40 PVC. Conduits shall be raised a minimum of 1 inch approximately over the concrete slab. Expanding foam Hilti Inc. CF810 shall be used to fill inside the conduits after the primary/secondary is installed. Ownership of cable will determine who installs the foam on each cable. After pulling tape is in, install the expanding foam in any spare/empty conduits. Place a rag into empty conduits prior to the foam as a support for the foam while curing takes place.

After the concrete pad is cured, the remainder of the conduit primary and secondary openings through pad will be sealed with grout. Before sealing steel sweeps, the sweeps must have a bond clamp attached with a #4 Cu tap to connect to the ground grid. Fill the conduit primary and secondary openings with sand (no aggregate) to a grade of approximately 2 inches below the top of the concrete pad. Place a layer of concrete grout (no aggregate) 1 to 2 inches thick on top of the sand layer to seal the conduit entrance. Do not cover the conduit ground clamps with grout. The expanding foam may be used as an alternate for filling in the opening with sand and concrete grout. Ownership of conduits and pad will determine who seals openings. See page 62 for further details in company bulletin 09-09 Three Phase Pad-mounted Transformer Sealing.

Expanding Foam CF810 available at Hilti Inc. 1-800-879-8000 Stuart C Irby Co 1-315-453-2970 and 1-315-329-0038

Spare conduits can also be sealed with conduit plugs, see page 54 for a list of manufacturers.

15.0 Transformer Grounding and Bonding

The ground grid shall be 2/0, bare, soft drawn, 19 strand copper wire. The wire shall be installed 12 inches below finished grade and located around the transformer pad as shown on page

17. Bond to all exposed metallic conduit and leave 3 feet of wire above pad for grounding transformer, one lead in the primary conduit window opening and the other lead in the secondary conduit window opening.

17 For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

Two 5/8 inch diameter, 8 feet long copper weld ground rods and approved connectors shall be installed to 12” below finished grade. Leave the ground rods and grid exposed until inspected the Company. The ground grid is to be complete and backfilled prior to energizing the transformer.

Connections to ground grid to be made as shown on Details A and B below, except that exothermic welding ("cad weld") shall be an acceptable alternative to a compression connection.

Bolted connectors are only acceptable for the ground grid connections to the ground rods.

The company will install the ground taps onto the transformer.

18 For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

16.0 Oil Containment

This is to be used where oil containment is required by local authorities or where otherwise justified.

This liner system will significantly slow the migration of oil into the under laying sub grade, allowing additional time to initiate a cleanup response. The polypropylene geotextile allows the passage of water but absorbs small quantities of oil. This design is intended to confine 100% of total transformer oil present, with a 20% reserve margin, for up to 36 hours. If additional confinement is desired consult the company Environmental Engineer. Follow the following installation steps. See Page 19 for construction detail. A precast containment barrier is available as an alternate to casting one in place, check with the precast suppliers on page 53 for availability. Precast curb can be one piece or made up of separate pieces assembled in the field.

Note: on field assembled pieces. All pieced must be sealed together with rope tar, rubber sealant or equivalent.

1) Build oil curb, this should be installed with concrete in accordance with Mix #4 per concrete specifications on pages 45 thru 48. Reinforcement to be #4, grade 60 rods minimum, 6 inches on center, bend rods around corners. Curb to be 24” deep with a minimum thickness of 6”.

2) Install geotextile liner from top of walls and around bottom of containment area. Areas where conduit crosses overlap liner around conduit and seal with expanding foam.

3) Install 6” of silty sand on top of liner.

4) Install second layer of geotextile liner as noted in step 2.

5) Build up area for transformer pad with 6” of compacted gravel and level.

6) Install ground grid.

7) Set/build transformer pad.

8) Fill in conduit openings with silty sand or expanding foam up to the last two inches of the pad

9) Fill rest of conduit opening with concrete grout or expanding foam.

10) Fill area between slab and curb with 1½ inches uniformly graded crushed rock.

Geo-textile Liner Generic name is: 16oz polypropylene geotextile also called filter fabric weighing 16oz/sqare yard.

Brand names/Suppliers are:

AME1680 available from American Engineering Fabrics (AEF), Inc.

(Emphasize polypropylene not polyester) New Bedford, MA@1-617-965-0007/1-800-770-2666 or from Vellano Bros. Lancaster NY 1-716-684-7222, several other locations in NY, MA, RI and NH, go to www.vellano.com

Synthetic Industries ST 160 available from Spartan Mills Inc’s, Spartanburg, NC 1-803-576-2353

Carthage Mills FX-160HS / US Construction Fabrics LLC 90 Range Rd, Windham NH 03087 1-603-898-0532

19For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

Containment Area Plan View

Typical Cross Section of Containment Pad A-A

For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

17.0 Riser Pole

The Company shall designate conduit riser locations on the pole. All primary risers shall be Galvanized Steel, this includes the 90 degree sweep. Per NESC all steel risers must be bonded 6” down from top of riser and the bond must be at least 8’ high from finished grade.

The Customer is responsible for providing and installing the bond clamps and the tap. The Company will make the bond connection from that riser bond tap to the ground system on the pole. Spare riser sweep shall be bonded also. Riser sweep in Direct Buried applications shall be concrete encased. Approved materials reference is located on page 54.

21For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

18.0 Heavy Duty Handhole

This primary conduit handhole may be specified in the design for installation in roadways or sidewalks areas where duct length requires extra pulling locations. Heavy duty handholes are supplied and installed by the Customer.

Notes:

1. Chimney height is kept to a minimum to facilitate placing completed splices in handhole from above grade.

2. Concrete minimum strength - See pages 45 thru 48.

3. Roof opening 3’ 2” inches x 3’ 2”.

4. Handhole frame, ring and cover are typically provided by the customer.

22 For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

19.0 Primary Cable Pull/Splice Box

This primary conduit Pull/Splice Box may be specified in the design for installation in sidewalks or grass plot areas where duct length or design requires extra pulling locations or splices. The splice box is H20 rated and shall be installed in locations not frequently traveled over by vehicles.

Pull/splice boxes are supplied and installed by the customer.

CDR

PA12-30-60-37-0016

23 For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

20.0 Trench Requirements

Final grades shall be established; the surface rough graded with in 6” from finished grade, roadway and property boundaries shall be staked or marked by the Customer before any trenching is started. Trench spoils shall be kept a distance of 2’ minimum from excavated trench.

The Customer shall adhere to the construction plan and specifications specifying trench locations, trench depth and concrete encasement. Any deviation shall be subject to approval by the Company.

The Company shall be notified in advance of the backfilling of any electric facility (e.g. concrete, conduit, manholes, riser bends). The Company reserves the right to require re-excavation of the conduits and foundations if the Customer fails to have inspection done or backfills before inspection.

Trenches shall not be backfilled until concrete has set (for at least two hours) and until after approval by authorized Company personnel. Note: if trench is subjected to traffic then the trench shall set for at least 12 hours. All backfill shall be sand or gravel containing stones less than 1" in any dimension. Backfilling shall not take place over any open-ended (unplugged) conduits.

Company approved red “Warning” tape shall be installed directly above the Company’s cable eight to twelve inches below finished grade. Laying the warning tape directly on the cable, concrete or conduit is not acceptable. Certain installations in the public way may require flowable fill instead in place of normal backfill.

20.1 Trench Depth New York/New England Concrete Encased Conduit Burial depths for electrical conduit shall be maintained not less than 30" from the top of the concrete encasement to grade during all phases of construction. The trench bottom shall be solid, undisturbed earth. Earth showing signs of peat, cinders, rubble, or any conditions not suitable for a stable foundation shall be reported to the Company for recommendation. Small pockets of unsuitable soil shall be replaced with compacted gravel (max. 2" stone). At riser pole end concrete encasement just before riser sweep.

20.2 Trench Depth Conduit Direct Buried New York (under certain circumstances agreeable with the company) Burial depths for electrical conduit shall be maintained not less than 30" from the top of the conduit to grade during all phases of construction. The trench bottom shall be solid, undisturbed earth.

Earth showing signs of peat, cinders, rubble, or any conditions not suitable for a stable foundation shall be reported to the Company for recommendation. Small pockets of unsuitable soil shall be replaced with compacted gravel (max. 2" stone).

20.3 Trench Depth Direct Buried New York

Burial depths for electrical cable shall be maintained not less than 30” to grade during all phases of construction. The trench bottom shall be solid, undisturbed earth. Earth showing signs of peat, cinders, rubble, or any conditions not suitable for a stable foundation shall be reported to the Company for recommendation. Small pockets of unsuitable soil shall be replaced with compacted gravel (max. 2" stone). Then 2” minimum of sand shall be the base to lay the cable on top of with another 4” minimum of sand to cover cable.

24 For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

Conduit Trench Conduit in Concrete Trench

Direct Burial Trench Legend

Notes:

1) If more than one set of primary is installed in the trench, separate primary by 6” minimum.

2) Nantucket MA area to use this trench with a spare 4” conduit to be installed at least 6” away from the direct burial cable.

Figure 20.0-1 Typical Trenches

Provided by Customer Warning Tape

25For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

21.0 Conduit Requirements

The Customer shall be responsible for all trenching, excavating, backfilling, and installation of the primary duct system. Exceptions to this shall be in areas where there is an existing manhole and duct system and the limits of trenching by the Customer shall be determined by the Company. The Customer is also responsible to supply and install any necessary manhole, pullboxes, heavy duty handholes, frames and covers. Concrete encasement shall be provided and installed by the Customer as specified by the Company.

The Customer shall ascertain the requirements of the specific municipality in which the development is located. For example, some municipalities may require that the Customer employ a licensed electrician to direct the installation of all conduit intended for electric facilities.

Temporary mechanical protection over buried conduit and encasements is recommended to prevent crushing or damage during construction. This is the Customer’s responsibility.

All road crossings shall, when practical, be perpendicular to the sidelines of the road.

The minimum size conduit shall be 4” schedule 60 DB. All sweeps at foundations and risers shall have a minimum radius of thirty-six inches (36"). The riser sweep shall be galvanized steel. The padmount transformer sweeps shall be galvanized rigid steel or schedule 40 - PVC, with the transformer sweeps rising typically 1" above the concrete pad. The customer shall install bell ends on the conduits. The Customer shall install conduit plugs in all unused conduits and pulling tape. At the riser pole, the galvanized rigid steel sweeps and the PVC/steel adaptors shall not be concrete encased. The Customer shall be responsible to install rigid galvanized steel straight conduit up the pole as shown on page 20, including conduit ground straps, up the riser pole (unless directed otherwise by the Company). The Company will specify on which quarter of the pole the riser shall be installed, usually away from oncoming traffic.

Except as noted on construction prints, curves and bends in conduit shall be gradual, and the radius of curvature shall not be less than forty feet. All curves shall be formed with 5-degree couplings. The minimum length between single, 5-degree couplings is 42". Heat bending is not allowed.

Conduit grade shall be such as to cause all ducts to drain toward one or both equipment foundations or pullboxes. Minimum pitch shall be three inches (3") per one hundred feet (100').

The Customer shall insure that clearances are met and maintained, and that they are inspected by the Company. Unless local jurisdictions require greater clearances, the minimum clearances shall be as follows:

Communication Systems – Company conduit shall not be directly above or below communication conduit, except when crossing below communication conduit at approximately right angles.

Company conduit and communication conduit shall be separated by a minimum of 3" of concrete encasement.

Water, Gas, Sewer – Company conduit shall not be directly above or below these utilities, except when crossing above these utilities at approximately right angles. Where the paths of these utilities cross under Company conduits at approximately right angles, the minimum separation is 12". A minimum separation of 24" shall be maintained between parallel placement of any of these utilities and electrical conduit.

A 6-inch clearance shall be between conduit envelopes and major subsurface pipes (e.g.

drainage pipes).

26 For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

The Customer shall mandrel all primary conduits to insure their integrity before the Company shall attempt to pull any primary cable. The Customer shall furnish and install an approved synthetic, 2,500 pound test tape in each primary conduit run including risers. Pulling tape installation and mandrilling the duct shall be witnessed by the Company.

Company owned duct shall not share a concrete encasement with foreign utilities (e.g. do not place communication or private electrical duct in the same concrete encasement as Company duct).

21.1 Pulling Tape

All conduits shall have a pulling tape, also known as “Mule Tape”. This tape is to be to be rated for 2,500#. Manufacturers of this tape are listed on page 54.

21.2 Trench and Conduit System Inspection

In the applicable area, a designated Company inspector shall be responsible for the inspection of the trench and or conduit system being prepared and installed by the Customer, at stages of installation. The Customer shall provide the Company inspector with a minimum of 24 to 72 hours notice. Required inspections are:

1) After conduit, ground system, reinforcing bars and forming are completed; but before concrete is poured.

2) After concrete is poured but before backfilling.

3) After backfilling.

The inspection shall not be limited to the above.

22.0 Primary Cable and Electrical Equipment

The majority of installations will have the Company provide, install, and maintain the entire primary electrical system including the transformer, cable, cable accessories, terminations, and other miscellaneous primary electrical system components.

In some areas the Customer will (mostly New Hampshire) provide and maintain the entire primary electrical system. The Company will provide install and maintain the transformer and other miscellaneous primary electrical system components.

The designation and location of the riser pole(s) shall be determined by the Company.

The location of primary cable pull/splice boxes and/or heavy duty handholes shall be determined by the Company.

At those locations where manholes or above ground switchgear are required, additional specifications will be provided by the Company.

23.0 Secondary Cable and Conduit System

Secondary cables shall be installed underground in customer/developer furnished, installed, owned and maintained conduit system or raceway. Conditions requiring more secondary cables than the Company's transformer secondary terminals can accommodate may require the customer/developer to supply an intermediate splice box to make a transition from National Electrical Code required cable capabilities (required to match main switch), to actual load cable capabilities. Page 56 lists manufacturers of the splice box.

27 For the latest authorized version, please refer to the company’s website at http://www.nationalgridus.com/electricalspecifications.

24.0 Metering

Refer to the Company’s Specifications for Electrical Installations book for the type of installation.

Division of work and material will be performed with the approval and authorization of the Company’s Metering Services Department.

25.0 Manhole

Manhole installation may be required as part of the infrastructure to serve certain customers.

The Customer shall provide and install the manhole to company specification. On page 53 lists precast concrete providers.