Attachment 2 UFGS 26 05 26.00 40.pdf

USACE / NAVFAC / AFCEC / NASA UFGS- 26 05 26. 00 40 ( August 2019) Pr epar i ng Act i v i t y: NASA Super sedi ng UFGS- 28 05 26. 00 40 ( August 2016)

UNI FI ED FACI LI TI ES GUI DE SPECI FI CATI ONS

Ref er ences ar e i n agr eement wi t h UMRL dat ed Januar y 2021

SECTION TABLE OF CONTENTS

DIVISION 26 - ELECTRICAL

SECTION 26 05 26.00 40

GROUNDING AND BONDING FOR ELECTRICAL SYSTEMS

08/19

PART 1 GENERAL

1.1 REFERENCES

1.2 SUBMITTALS

1.3 QUALITY CONTROL

1.3.1 Regulatory Requirements

1.3.2 Standard Products

1.3.3 Ground Resistance Test Equipment

1.3.4 Micro-Ohmmeter Test Equipment

1.4 PREDICTIVE TESTING AND INSPECTION TECHNOLOGY REQUIREMENTS

PART 2 PRODUCTS

2.1 MATERIALS

2.1.1 Ground Rods

2.1.2 Ground Wires

2.1.2.1 Bare

2.1.2.2 Insulated

2.1.2.3 Straps/Jumpers

2.1.3 Connectors and Fasteners

2.1.3.1 Exothermic Welds

2.1.3.2 Irreversible Compression Lugs

2.1.3.3 Mechanical

2.1.3.4 Fasteners

2.1.4 Test Wells

2.1.5 Conductive Corrosion Inhibiting Compounds

2.1.6 Ground Buses

PART 3 EXECUTION

3.1 INSTALLATION

3.1.1 Ground Rods

3.1.2 Conductors

3.1.3 Counterpoise

3.1.4 Ground Buses

3.1.5 Building Grounds

SECTION 26 05 26.00 40 Page 1

3.1.6 Equipment Grounding

3.1.6.1 Equipment and Enclosure Bonding

3.1.6.2 Bonding of Conduit and Raceway Systems

3.1.6.3 Cable Tray Bonding

3.1.7 Bonding Materials And Methods

3.1.7.1 Brazing

3.1.7.2 Welding

3.1.7.3 Clamping

3.1.7.4 Cleaning of Bonding Surfaces

3.1.7.5 Protection of Finished Bonds

3.2 FIELD QUALITY CONTROL

3.2.1 Bond Resistance Test

3.2.2 Ground Resistance Tests

3.2.3 Ground Isolation Test

3.2.4 Equipment Continuity Test

3.3 CLOSEOUT ACTIVITIES

-- End of Section Table of Contents --

SECTION 26 05 26.00 40 Page 2

USACE / NAVFAC / AFCEC / NASA UFGS- 26 05 26. 00 40 ( August 2019) Pr epar i ng Act i v i t y: NASA Super sedi ng UFGS- 28 05 26. 00 40 ( August 2016)

UNI FI ED FACI LI TI ES GUI DE SPECI FI CATI ONS

Ref er ences ar e i n agr eement wi t h UMRL dat ed Januar y 2021

SECTION 26 05 26.00 40

GROUNDING AND BONDING FOR ELECTRICAL SYSTEMS

08/19

NOTE: Thi s gui de speci f i cat i on cover s t he r equi r ement s f or el ect r i cal syst em and equi pment gr oundi ng i ncl udi ng gr ound r ods, gr oundi ng conduct or s, connect or s, and ot her accessor i es. Thi s sect i on excl udes i nst r ument at i on and st at i c gr oundi ng syst ems.

Ensur e dr awi ngs show pl an l ayout of each gr oundi ng el ect r ode, gr ound mat , gr ound gr i d, subst at i on gr ound bus, i nt er connect i ng gr oundi ng conduct or , and t ap connect i ons t o st eel bui l di ng col umns and out door el ect r i cal equi pment . Ensur e t hat det ai l dr awi ngs of gr ound mat s and gr ound gr i ds show;

conf i gur at i on, gr ound r od spaci ngs, i nt er connect i ng cabl e and t ap connect i ons t o subst at i on yar d f ence, subst at i on gr ound bus, and i nt er i or equi pment .

When gr oundi ng syst ems as shown f ai l t o achi eve t he desi r ed measur ed r esi st ance t o gr ound, addi t i onal gr ound r ods may be r equi r ed.

Adher e t o UFC 1-300-02 Uni f i ed Faci l i t i es Gui de Speci f i cat i ons ( UFGS) For mat St andar d when edi t i ng t hi s gui de speci f i cat i on or pr epar i ng new pr oj ect speci f i cat i on sect i ons. Edi t t hi s gui de speci f i cat i on f or pr oj ect speci f i c r equi r ement s by addi ng, del et i ng, or r evi s i ng t ext . For br acket ed i t ems, choose appl i cabl e i t em( s) or i nser t appr opr i at e i nf or mat i on.

Remove i nf or mat i on and r equi r ement s not r equi r ed i n r espect i ve pr oj ect , whet her or not br acket s ar e present.

Comment s, suggest i ons and r ecommended changes f or t hi s gui de speci f i cat i on ar e wel come and shoul d be submi t t ed as a Criteria Change Request (CCR) .

SECTION 26 05 26.00 40 Page 3

PART 1 GENERAL

I f Li ght i ng Pr ot ect i on i s r equi r ed as par t of t he pr oj ect i ncl ude Sect i on 26 41 00 LI GHTNI NG PROTECTI ON SYSTEMS and i ncl ude r ef er ence i n second paragraph.

[ Section 26 20 00 INTERIOR DISTRIBUTION SYSTEM applies to work specified in this section.

][ Section 26 41 00 LIGHTNING PROTECTION SYSTEMS applies to work specified in this section.

] 1.1 REFERENCES

NOTE: Thi s par agr aph i s used t o l i s t t he publ i cat i ons c i t ed i n t he t ext of t he gui de speci f i cat i on. The publ i cat i ons ar e r ef er r ed t o i n t he t ext by basi c desi gnat i on onl y and l i s t ed i n t hi s par agr aph by or gani zat i on, desi gnat i on, dat e, and t i t l e.

Use t he Ref er ence Wi zar d' s Check Ref er ence f eat ur e when you add a Ref er ence I dent i f i er ( RI D) out si de of t he Sect i on' s Ref er ence Ar t i c l e t o aut omat i cal l y pl ace t he r ef er ence i n t he Ref er ence Ar t i c l e. Al so use t he Ref er ence Wi zar d' s Check Ref er ence f eat ur e t o updat e t he i ssue dat es.

Ref er ences not used i n t he t ext wi l l aut omat i cal l y be del et ed f r om t hi s sect i on of t he pr oj ect speci f i cat i on when you choose t o r econci l e r ef er ences i n t he publ i sh pr i nt pr ocess.

The publications listed below form a part of this specification to the extent referenced. The publications are referred to within the text by the basic designation only.

AMERICAN WELDING SOCIETY (AWS)

AWS A3.0M/A3.0 (2020) Standard Welding Terms and Definitions

AWS A5.8/A5.8M (2019) Specification for Filler Metals for Brazing and Braze Welding

AWS B2.1/B2.1M (2014; Errata 2015) Specification for Welding Procedure and Performance Qualification

ASTM INTERNATIONAL (ASTM)

ASTM B3 (2013) Standard Specification for Soft or Annealed Copper Wire

SECTION 26 05 26.00 40 Page 4

ASTM B8 (2011; R 2017) Standard Specification for Concentric-Lay-Stranded Copper Conductors, Hard, Medium-Hard, or Soft

ASTM B187/B187M (2020) Standard Specification for Copper, Bus Bar, Rod and Shapes and General Purpose Rod, Bar and Shapes

INSTITUTE OF ELECTRICAL AND ELECTRONICS ENGINEERS (IEEE)

IEEE 81 (2012) Guide for Measuring Earth Resistivity, Ground Impedance, and Earth Surface Potentials of a Ground System

IEEE C2 (2017; Errata 1-2 2017; INT 1 2017) National Electrical Safety Code

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION (NASA)

RCBEA GUIDE (2004) NASA Reliability Centered Building and Equipment Acceptance Guide

NATIONAL ELECTRICAL MANUFACTURERS ASSOCIATION (NEMA)

ANSI/NEMA GR 1 (2007) Grounding Rod Electrodes and Grounding Rod Electorode Couplings

NATIONAL FIRE PROTECTION ASSOCIATION (NFPA)

NFPA 70 (2020; ERTA 20-1 2020; ERTA 20-2 2020; TIA

20-1; TIA 20-2; TIA 20-3; TIA 20-4)

National Electrical Code

NFPA 780 (2017) Standard for the Installation of Lightning Protection Systems

TELECOMMUNICATIONS INDUSTRY ASSOCIATION (TIA)

TIA-607 (2015c; Addendum 1 2017) Generic Telecommunications Bonding and Grounding (Earthing) for Customer Premises

U.S. DEPARTMENT OF DEFENSE (DOD)

MIL-STD-889 (2016; Rev C) Dissimilar Metals

UNDERWRITERS LABORATORIES (UL)

UL 467 (2013; Reprint Jun 2017) UL Standard for Safety Grounding and Bonding Equipment

UL 546 (2008) UL Outline of Investigation for Conductor Termination Compounds

1.2 SUBMITTALS

NOTE: Revi ew Submi t t al Descr i pt i on ( SD) def i ni t i ons i n Sect i on 01 33 00 SUBMI TTAL PROCEDURES and edi t

SECTION 26 05 26.00 40 Page 5 t he f ol l owi ng l i s t , and cor r espondi ng submi t t al i t ems i n t he t ext , t o r ef l ect onl y t he submi t t al s r equi r ed f or t he pr oj ect . The Gui de Speci f i cat i on t echni cal edi t or s have cl assi f i ed t hose i t ems t hat r equi r e Gover nment appr oval , due t o t hei r compl exi t y or cr i t i cal i t y, wi t h a " G. " Gener al l y, ot her submi t t al i t ems can be r evi ewed by t he Cont r act or ' s Qual i t y Cont r ol Syst em. Onl y add a “ G” t o an i t em, i f t he submi t t al i s suf f i c i ent l y i mpor t ant or compl ex i n cont ext of t he pr oj ect .

For Ar my pr oj ect s, f i l l i n t he empt y br acket s f ol l owi ng t he " G" c l assi f i cat i on, wi t h a code of up t o t hr ee char act er s t o i ndi cat e t he appr ovi ng aut hor i t y. Codes f or Ar my pr oj ect s usi ng t he Resi dent Management Syst em ( RMS) ar e: " AE" f or Ar chi t ect - Engi neer ; " DO" f or Di st r i ct Of f i ce ( Engi neer i ng Di v i s i on or ot her or gani zat i on i n t he Di st r i ct Of f i ce) ; " AO" f or Ar ea Of f i ce; " RO" f or Resi dent Of f i ce; and " PO" f or Pr oj ect Of f i ce. Codes f ol l owi ng t he " G" t ypi cal l y ar e not used f or Navy, Ai r For ce, and NASA pr oj ect s.

The " S" c l assi f i cat i on i ndi cat es submi t t al s r equi r ed as pr oof of compl i ance f or sust ai nabi l i t y Gui di ng Pr i nci pl es Val i dat i on or Thi r d Par t y Cer t i f i cat i on and as descr i bed i n Sect i on 01 33 00

SUBMI TTAL PROCEDURES.

Choose t he f i r st br acket ed i t em f or Navy, Ai r For ce and NASA pr oj ect s, or choose t he second br acket ed i t em f or Ar my pr oj ect s.

Government approval is required for submittals with a "G" or "S" classification. Submittals not having a "G" or "S" classification are [for Contractor Quality Control approval.][for information only. When used, a code following the "G" classification identifies the office that will review the submittal for the Government.] Submit the following in accordance with Section 01 33 00 SUBMITTAL PROCEDURES:

SD-03 Product Data

Ground Rods ; G[, [____]]

Ground Wires ; G[, [____]]

Connectors and Fasteners ; G[, [____]]

Test Wells ; G[, [____]]

Conductive Corrosion Inhibiting Compounds ; G[, [____]]

Ground Buses ; G[, [____]]

SD-06 Test Reports

Bond Resistance Test ; G[, [____]]

SECTION 26 05 26.00 40 Page 6

Ground Resistance Tests ; G[, [____]]

Ground Isolation Test ; G[, [____]]

Equipment Continuity Test ; G[, [____]]

SD-07 Certificates

Ground Resistance Test Equipment ; G[, [____]]

Micro-Ohmmeter Test Equipment ; G[, [____]]

SD-11 Closeout Submittals

Record Drawings

1.3 QUALITY CONTROL

1.3.1 Regulatory Requirements

In each of the publications referred to herein, consider the advisory provisions to be mandatory, as though the word, "shall" had been substituted for "should" wherever it appears. Interpret references in these publications to the "authority having jurisdiction," or words of similar meaning, to mean the Contracting Officer. Ensure equipment, materials, installation, and workmanship are in accordance with the mandatory and advisory provisions of NFPA 70 , IEEE C2 unless more stringent requirements are specified or indicated.

1.3.2 Standard Products

Provide materials and equipment that are products of manufacturers regularly engaged in the production of such products which are of equal material, design and workmanship. Provide products which have been in satisfactory commercial or industrial use for 2 years prior to bid opening. Ensure the 2-year period includes applications of equipment and materials under similar circumstances and of similar size. Ensure the product has been on sale on the commercial market through advertisements, manufacturers' catalogs, or brochures during the 2-year period. Where two or more items of the same class of equipment are required, these items must be products of a single manufacturer.

1.3.3 Ground Resistance Test Equipment

Provide combination 3-point and 4-point type ground resistance test equipment specifically designed for grounding electrode resistance and soil resistivity tests. Submit proof of current equipment calibration with test equipment product data.

1.3.4 Micro-Ohmmeter Test Equipment

Perform [circuit and ]bond resistance tests using a micro-ohmmeter with the following characteristics:

a. Resistance range selectable and capable of measuring to 10 micro-Ohms using a minimum of 1 ampere of test current.

b. Positive and negative test leads of the 2-wire balanced type.

Provide both clamp and probe type connections to allow measurements

SECTION 26 05 26.00 40 Page 7 across all bonded surfaces. Provide long length balanced test lead to allow measurements from a bonding location to the nearest test well.

Submit proof of current equipment calibration with test equipment product data.

1.4 PREDICTIVE TESTING AND INSPECTION TECHNOLOGY REQUIREMENTS

NOTE: The Pr edi ct i ve Test i ng and I nspect i on ( PT&I ) t est s pr escr i bed i n Sect i on 01 86 26. 07 40

RELI ABI LI TY CENTERED ACCEPTANCE FOR ELECTRI CAL

SYSTEMS ar e MANDATORY f or al l NASA asset s and syst ems i dent i f i ed as Cr i t i cal , Conf i gur ed, or Mi ssi on Essent i al . I f t he syst em i s non- cr i t i cal , non- conf i gur ed, and not mi ssi on essent i al , use sound engi neer i ng di scr et i on t o assess t he val ue of addi ng t hese addi t i onal t est and accept ance r equi r ement s.

See Sect i on 01 86 26. 07 40 RELI ABI LI TY CENTERED ACCEPTANCE FOR ELECTRI CAL SYSTEMS f or addi t i onal i nf or mat i on r egar di ng cost f easi bi l i t y of PT&I .

This section contains systems and equipment components regulated by NASA's Reliability Centered Building and Equipment Acceptance Program. This program requires the use of Predictive Testing and Inspection (PT&I) technologies in conformance with RCBEA GUIDE to ensure building equipment and systems have been installed properly and contain no identifiable defects that shorten the design life of a system and its components.

Satisfactory completion of all acceptance requirements is required to obtain Government approval and acceptance of the work.

Perform PT&I tests and provide submittals as specified in Section

01 86 26.07 40 RELIABILITY CENTERED ACCEPTANCE FOR ELECTRICAL SYSTEMS.

PART 2 PRODUCTS

Submit material, equipment, and fixture lists for grounding systems, including manufacturer's style or catalog numbers, specification and drawing reference numbers, warranty information, and fabrication site information.

2.1 MATERIALS

2.1.1 Ground Rods

Provide ground rods of [copper][copper-clad steel] conforming to UL 467 and ANSI/NEMA GR 1 . Ensure ground rods are not less than[ 20 mm 3/4 inch in diameter and 3000 mm 10 feet in length][as indicated].

Where ground rod length is greater than 3000 mm10 feet , provide sectional type ground rods with each section 3000 mm10 feet in length. Join sectional type ground rods using [threaded brass couplings][exothermic welding completely around both rod/coupling joints][threaded couplings that are welded at the threaded joints]. Ensure ground rods have cone-shaped point on the end of the first section driven into the ground.

Provide ground rods and ground rod sections die-stamped near the top with the name or trademark of the manufacturer and the length of the segment in

SECTION 26 05 26.00 40 Page 8 feet.

2.1.2 Ground Wires

2.1.2.1 Bare

Provide annealed bare copper, Class "B" stranded ground and bond wires in accordance with ASTM B8 for wires #4 AWG and larger and solid in accordance with ASTM B3 for wires #6 AWG and smaller. Provide conductors with 98 percent conductivity and sized wires in accordance with the requirements of NFPA 70 and NFPA 780 .

2.1.2.2 Insulated

Ensure insulated conductors conform to the requirements of Section

26 05 00.00 40 COMMON WORK RESULTS FOR ELECTRICAL.

Where installed in conduit as part of a complete circuit provide conductors with green insulation for sizes #8 AWG and smaller and with green phase tape at each end and in each junction box for sizes #6 AWG and larger.

2.1.2.3 Straps/Jumpers

Provide copper bonding straps and jumpers with a cross-sectional area of not less than [4.12 millimeter diameter][as indicated] [No. 6 AWG][as indicated] . Ensure bonding straps and jumpers for shock-mounted devices with [pivot] [hinged] [swivel] joints are made of [flat] [tinned-copper] [woven-wire braid] [flexible stranded] wire.

2.1.3 Connectors and Fasteners

2.1.3.1 Exothermic Welds

Ensure the molds, materials and powder charges used to make exothermic welds are the standard product of a single manufacturer and listed by the manufacturer for use on the specific type, size, quantity and configuration of conductors to which the weld is applied.

2.1.3.2 Irreversible Compression Lugs

Provide irreversible compression lug type connectors manufactured from tin-plated copper and installed using a hydraulic compression tool and die to apply correct, uniformly distributed, circumferential pressure. Ensure tools and dies are as recommended by the irreversible compression lug type connector manufacturer. Use an embossing die code or other standard method to provide visible indication that a connector has been adequately compressed onto the conductor. Apply irreversible compression lug type connectors in strict accordance with the manufacturer's written instructions and published installation instructions. Use 2-hole lug type connectors for connections to NEMA cable pads and bus bars, and single-hole connectors otherwise.

2.1.3.3 Mechanical

Provide split bolt and clamp style mechanical type connectors manufactured from [copper, ][copper alloy, ][or ][bronze,] listed by the manufacturer as suitable for direct burial use. Ensure mechanical type connectors are applied in strict accordance with the manufacturer's published

SECTION 26 05 26.00 40 Page 9 installation instructions.

2.1.3.4 Fasteners

Provide bolts, nuts, washers, lock washers, and associated fasteners used for grounding and bonding connections manufactured of [copper][bronze][tin plated tempered brass][stainless steel]. Where fasteners contact dissimilar metals, apply conductive oxide-inhibiting compound.

[ 2.1.4 Test Wells

Provide test wells that are H2O rated, precast reinforced concrete, [circular][rectangular], with open bottom and concrete or cast iron lid/frame. Ensure test wells have inside dimensions of not less than [15 inches wide by 22 inches long][12 inches in diameter] by 24 inches deep.

Provide test well lid with cast "GROUND" legend.

] 2.1.5 Conductive Corrosion Inhibiting Compounds

Provide conductive corrosion inhibiting compounds UL Listed in accordance with UL 546 , listed by the manufacturer as suitable for the application, and suitable for all aluminum and copper conductor/connector applications. Ensure conductive corrosion inhibiting compounds inhibit oxidation at the conductor/connector interface and have no deleterious effect on the conductor/connector metal or EPDM, natural rubber, or polyethylene insulating materials. [

Provide gritted conductive corrosion inhibiting compound that are non-petroleum based and non-toxic, and contain conductive grit. Ensure gritted conductive corrosion inhibiting compound is specified by the manufacturer for application to the conductor/connector interface of compression connectors.] [

Provide non-gritted conductive corrosion inhibiting compound that are non-petroleum based and non-toxic and contain no grit filler. Ensure non-gritted conductive corrosion inhibiting compound is specified by the manufacturer for application to the conductor/connector interface of mechanical connectors such as bolted joints, flat-to-flat contact surfaces, terminal and lug tongues, and grooves of bolted parallel connectors or clamps.]

2.1.6 Ground Buses

Provide [electro-tin plated, ]solid copper ground buses conforming to ASTM B187/B187M with minimum dimensions of 6 millimeters 0.25 inches thick, 100 millimeters 4 inches wide, and 300 millimeters 12 inches in length or as indicated. Ensure ground buses are equipped with two UL Recognized red 1000V rated insulated standoffs and stainless steel mounting brackets.

Provide Telecommunications Main Ground Buses and Telecommunications Ground Buses in meeting the standards of TIA-607 .

Provide grounding buses with predrilled NEMA hole configuration as indicated.

SECTION 26 05 26.00 40 Page 10

PART 3 EXECUTION

3.1 INSTALLATION

Install grounding systems in accordance with NFPA 70 , NFPA 780 and IEEE C2 , and as indicated.

Bond exposed non-current-carrying metallic parts of electrical equipment and metallic raceway systems to ground.

Bond grounding conductors in metallic and non-metallic raceways to ground. Make ground connections at equipment and to ground rods as indicated. Interconnect all grounding media in or on the structure to provide a common ground potential. This includes lightning protection, electrical service, telecommunications system grounds, as well as underground metallic piping systems.

Bond wiring system neutrals to ground in accordance with the requirements of NFPA 70 . Where ground fault protection is employed, ensure that connection of ground and neutral does not interfere with correct operation of fault protection. [

Counterpoise ground systems consist of a series of ground rods with a direct buried grounding conductor loop, configured to minimize the number of dead-ends, interconnecting the individual ground rods. Provide ground rods in the locations indicated. ]

3.1.1 Ground Rods

NOTE: I n l ocat i ons wher e exi st i ng under gr ound ut i l i t i es, equi pment or st r uct ur es may be damaged, use t he wat er j et t i ng met hod f or gr ound r od installation.

[Install ground rods using a water jetting procedure.]

[ Install ground rods so that the top of the rod is [100] [_____] millimeter [4] [_____] inches above grade.

][ Install ground rods so that the top of the rod is not less than [450] [_____] millimeter [18] [_____] inches below finished grade.

] 3.1.2 Conductors

Install bare or insulated conductors as indicated. Install bare conductors where not specifically identified as bare or insulated except where installed in conduit with associated phase conductors. Install insulated conductors in conduit with insulation of the same material as the associated phase conductors with which it is installed.

Provide straps/jumpers across joints subject to vibration. Install strap/jumper such that vibration will not change its electrical characteristics. Apply strap/jumper to the metallic structure on each side of the joint; do not penetrate any adjacent parts. Install straps/jumpers in areas that are accessible for maintenance. Install strap/jumper such that it does not restrict the movement of the metallic structures to which it is connected. Install strap/jumper such that it does not weaken the

SECTION 26 05 26.00 40 Page 11 metallic structures to which it is attached. Do not connect two or more straps/jumpers in series.

3.1.3 Counterpoise

Install [11.7] [_____] millimeter diameter (No. [4/0] [_____] AWG) No.

[4/0] [_____] AWG bare copper counterpoise grounding conductor direct buried outside of the structure drip line, within 600 to 1800 millimeters 24 to 72 inches of the structure foundation, with a minimum of 450 millimeters 18 inches of earth cover. Install counterpoise grounding conductor in earth undisturbed by excavation, not earth fill, and do not locate beneath roof overhang, or wholly under paved areas or roadways where rainfall cannot penetrate to keep soil moist in the vicinity of the conductor.

Install ground rods vertically into the earth not less 3000 mm 10 feet with top of ground rod not less than [450] [_____] millimeter [18] [_____] inches below finished grade. Bond ground rods to counterpoise grounding conductor at intervals no less than 6 linear meters 20 linear feet nor greater than 12 linear meters 40 linear feet of ground counterpoise cable.

3.1.4 Ground Buses

Install ground busses in accordance with manufacturer's instructions.

3.1.5 Building Grounds

Install [11.7] [_____] millimeter diameter (No. [4/0] [_____] AWG) No.

[4/0] [_____] AWG bare copper ground conductor from [concrete encased foundation rebar][ and ][every corner column and intermediate exterior column] to counterpoise. [Connect conductors to rebar using [mechanical connectors manufactured for such purpose][exothermic welds]. Install one conductor a minimum of every [18,000] [_____] millimeter [60] [_____] feet of concrete foundation perimeter. ]Connect ground conductors to [columns and ]counterpoise using [mechanical connectors manufactured for such purpose][exothermic welds].

3.1.6 Equipment Grounding

Install ground systems for power, telecommunications, and instrumentation. Independently connect each system to the building counterpoise.

3.1.6.1 Equipment and Enclosure Bonding

Bond each metallic enclosure and all electrical equipment to ground. Make at least one copper connection from the system ground point to one or more enclosures in the area such that all enclosures and equipment provide a low-impedance path to ground when properly bonded together.

NOTE: Thi s par agr aph speci f i es a " Case" gr ound. A Case gr ound i s wher e gr oundi ng i s cr i t i cal such as f uel i ng ar eas, pads, et c. A modi f i cat i on such as an of f i ce bui l di ng or an admi ni st r at i ve ar ea woul d not r equi r e t he addi t i onal gr ound.

SECTION 26 05 26.00 40 Page 12

[ In addition to the green colored equipment grounding conductor required in each raceway and sized in accordance with Table 250.122 of NFPA 70 , bond each panelboard, switchboard enclosure, transformer housing, motor housing, disconnect, starter, and other electrical equipment, to the grounding system with a stranded copper conductor, routed external to the feeder raceway.

] Individually and directly connect indoor substations, transformers, switchboard frames, switchgear assemblies, motors, motor control centers, air compressors, air handlers, refrigerated air dryers, generators, frames and tracks of cranes, and [_____] to the building ground. Ensure the current-carrying capacity of the grounding conductor is the same as the current-carrying capacity of the power conductors for circuits utilizing power lines size [6.54] [_____] millimeter diameter (No. [2] [_____] AWG) No. [2] [_____] AWG and smaller. For circuits with power wiring larger than [6.54] [_____] millimeter diameter (No. [2] [_____] AWG) No. [2] [_____] AWG , ensure the grounding conductor is in accordance with NFPA 70 .

3.1.6.2 Bonding of Conduit and Raceway Systems

Bond all metal conduit, fittings, junction boxes, outlet boxes, armored and metal sheathed cable, and other raceways. Ensure adequate electrical contact at the joints and terminations. Ensure metallic raceway systems have electrical continuity with equipment. Individually and directly connect equipment to the building ground, independent of the raceway system.

For rigid metal conduit and terminations, ensure threaded connections are wrench-tight with no exposed threads. Ream all ends of the conduit to remove burrs and rough edges. Bond conduits entering boxes and enclosures to the box with [bonding-type locknuts, one outside and one inside.] [locknuts and grounding-type bushings.] Locknuts that gouge into the metal box when tightened are not acceptable.

Conduit systems that are interrupted by PVC dielectric links are bonded separately on either side of the link. Do not jumper the dielectric link.

Install flexible metal conduit with an integral grounding conductor.

3.1.6.3 Cable Tray Bonding

Bond cable tray sections together. Cable tray sections in tandem assembly are considered as having electrical continuity when these sections are bonded with the appropriate bolts. Install bond straps across expansion joints. Bond cable trays to the building ground system.

3.1.7 Bonding Materials And Methods

Accomplish bonding of metal surfaces by [brazing] [welding] [clamping] [structural joining methods].

3.1.7.1 Brazing

Ensure brazing solder conforms to AWS A5.8/A5.8M [_____].

3.1.7.2 Welding

Weld using the exothermic process with procedures conforming to AWS A3.0M/A3.0 , AWS B2.1/B2.1M , and manufacturer's recommendation. Where

SECTION 26 05 26.00 40 Page 13 dissimilar metals are to be joined via exothermic weld, follow the weld kit manufacturer's recommendations and published instructions. Ensure connections between dissimilar metals do not produce galvanic action in accordance with MIL-STD-889 .

Use welding processes of the exothermic fusion type that makes a connection without corroding or loosening. Ensure process joins all strands and does not cause the parts to be damaged or weakened. Completed connection or joint is equal or larger in size than the conductors joined and has the same current-carrying capacity as the largest conductor.

Paint the buried ground connections with a bitumastic paint.

3.1.7.3 Clamping

In external locations, use clamping only where a disconnect type of connection is required. Connection device may utilize [spring-loaded jaws] [threaded fasteners]. Construct device such that positive contact pressure is maintained at all times. Use machine bolts with [tooth-type] [spring-type] lockwashers.

3.1.7.4 Cleaning of Bonding Surfaces

Thoroughly clean surfaces that comprise the bond before joining. Apply an appropriate abrasive with gentle and uniform pressure to ensure a smooth and uniform surface. Do not remove excessive metal from the surface.

Clean clad metals in such a manner that the cladding material is not penetrated by the cleaning process. Then clean bare metal with an appropriate solvent to remove any grease, oil, dirt, corrosion preventives, and other contaminants. Bond to the cleaned area within one hour after cleaning. Seal joint and refinish the exposed surfaces within two hours of exposure to prevent oxidation. When additional time is required, apply a corrosion preventive compound until the area can be refinished.

3.1.7.5 Protection of Finished Bonds

Protect finished bonds by painting to match the original finish after the bond is made.

3.2 FIELD QUALITY CONTROL

NOTE: I f t he speci f i ed syst em i s i dent i f i ed as cr i t i cal , conf i gur ed, or mi ssi on essent i al , use Section 01 86 26. 07 40 RELI ABI LI TY CENTERED ACCEPTANCE FOR ELECTRI CAL SYSTEMS t o est abl i sh pr edi ct i ve and accept ance t est i ng cr i t er i a.

Perform PT&I tests and provide submittals as specified in Section

01 86 26.07 40 RELIABILITY CENTERED ACCEPTANCE FOR ELECTRICAL SYSTEMS.

[ The requirements of Section 26 08 00 APPARATUS COORDINATION, INSPECTION AND TESTING apply to this section.

] Perform the following tests in the presence of the Contracting Officer.

Furnish test equipment and personnel and submit written results of each test. Notify the Contracting Officer at least 14 calendar working days prior to each test.

SECTION 26 05 26.00 40 Page 14

Submit written results of each test to Contracting Officer for review and approval. Document each location where test is performed, the field conditions at the time of the test, the measured results of the test, and whether the measured results "PASSED" or "FAILED" relative to specified pass/fail performance criteria.

Perform rework to correct FAILED conditions at no additional cost to the Government.

3.2.1 Bond Resistance Test

Resistance of any bond connection cannot exceed [0.5] [_____] milliohm.

Rework bonds that exceed this resistance at no additional cost to the Government.

3.2.2 Ground Resistance Tests

Test grounding systems for ground resistance. Total resistance from any point on the ground network to the building counterpoise cannot exceed [50] [_____] milliohms.

Make ground resistance and counterpoise tests during dry weather, and no sooner than [48] [_____] hours after rainfall. Conduct tests using the ratio method that measures the ratio of the resistance to earth of an auxiliary test electrode to the series resistance of the electrode under test and a second auxiliary electrode. Perform measurements in accordance with IEEE 81 .

3.2.3 Ground Isolation Test

Test ground systems for isolation from other ground systems.

3.2.4 Equipment Continuity Test

Test connection from electrical distribution equipment including panelboards, switchboards, transformers, substations, and motor control centers to counterpoise. Measure and record the circuit resistance between electrical equipment ground connections and the counterpoise. The circuit resistance shall not exceed [5][ ] Ohms.

3.3 CLOSEOUT ACTIVITIES

Submit record drawings indicating the location of ground rods, mats, grids, building ground bus, supplementary grounding electrodes, steel building columns, and other metal structures connected to the grounding system.

-- End of Section --

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