16452 grounding

7/27/2019 16452 Grounding

1/6

SECTION 16452

GROUNDING

00000000PART 1 - GENERAL

1.1 DESCRIPTION:

A. The Work shall consist of furnishing and installation of the grounding system asshown on the drawings and specified herein.

B. This work shall include grounding for power and grounding for telecommunication.

1.2 REFERENCES:

A. SASO Saudi Arabian Standards Organization

SASO 981-986 Electrical installations of buildings (all parts)

SASO 1270 Electrical installations of buildings: Part 5: Selection anderection of electrical equipment - Chapter 54: Earthingarrangements and protective conductors.

SASO 1486 Earthing electrodes

SASO 1487 Methods of testing earthing electrodes

SASO 1357 Electrical installations of buildings - Part 7: Requirements

for special installation or locations - Section 707: Earthingrequirements for the installation of data

SASO 1614 Protection of structures against lightning - Part 1: Generalprinciples - Section 1: Guide A. Section of protection levelsfor lightning protection systems

B. IEC - International Electro-technical Commission

IEC 60364 Electrical installations of buildings (all parts)

IEC 60364-5-54 Earthing arrangement and protective conductors

C. NFPA - National Fire Protection Association

NFPA 70 National Electrical Code

NFPA 780 Lightning Protection Code

D. UL - Underwriters Laboratories, Inc.

UL 467 Electrical Grounding and Bonding Equipment

UL 486A Wiring connectors and Soldering Lugs for With Copper

Conductors

ITCC in RiyadhResidential ComplexJ10-13300

16452-1Grounding

System

7/27/2019 16452 Grounding

2/6

UL 486B Wire Connectors for Use With Aluminum Conductors

UL 869 Service Equipment

E. IEEE - Institute of Electrical and Electronics Engineers

IEEE 81 Guide for Measuring Earth Resistivity, Ground Impedance,and Earth Surface

F. BS British Standards Institute

BS 6651 Protection of Structures against lightning

BS 7671 IEE Wiring Regulations

G. TIA/EIA

TIA/EIA J-STD-607-A Commercial Building Grounding and Bonding Requirementsfor Telecommunications

1.3 SUBMITTALS:

A. Shop Drawings: Showing the location of system grounding electrode connectionsand the routing of grounding electrode conductor.

B. Test Reports: Certified test reports of ground resistance.

C. Product Data and Material Samples.

1.4 QUALITY ASSURANCE:

A. Materials and equipment together with method of installation shall comply in allrespects with SASO, IEC and IEE Regulations for Electrical Installations, latestedition and other applicable Codes and Standards specified herein.

B. Telecommunication Grounding shall follow TIA/EIA J-STD-607-A.

PART 2 - PRODUCTS

2.1 MATERIALS:

A. GROUND CABLE:

1. Ground cables shall be soft drawn, bare stranded copper wire conforming toIEC 228, or insulated stranded copper wire conductor cable, as shown on thedrawings. The grounding cable shall have a minimum section in accordancewith SASO, IEC or NEC 250 and in no case smaller than 2.5 mm (AWG 12).

B. GROUND RODS


16452-2Grounding

System

7/27/2019 16452 Grounding

3/6

1. Unless otherwise indicated on Drawings, ground rods shall be coppercladded steel with high strength steel core and electrolytic-grade copperouter sheath, molten welded to core, 19 mm diameter rods, furnished in3.00 meters length. Ground rods shall be driven with a cap and driven stud.Ground conductors shall be laid with slack and buried to a minimum depthof 600 mm below grade.

C. TNS SYSTEM

1. As shown on Drawings, grounding system outside building shall be TNCsystem and inside building shall be TNS system. TNS system should haveonly one point which is directly connected to earth. This point shall be at theservice entrance which is the main low voltage power panel. From that pointthe neutral and the protective earth conductors must be separated and not bemixed together at any point of the secondary distribution system..

PART 3 - EXECUTION

3.1 GENERAL REQUIREMENTS:

A. The complete grounding system shall be mechanically and electrically continuousand of durable construction, providing an independent current return path of lowresistance to ground sources.

B. Tees and straight through joints in copper strip should be made either by rivetingand sweating, welding or brazing.

C. Where connections between dissimilar metals must be made, these should beprotected by painting over with a moisture resisting bituminous paint or compound,or by wrapping with a protective tape to exclude moisture.

D. Bolted connections shall be of the multiple bolt type. Bolts, washers and stop nutsshall be of high copper alloy, everdur, durium, duronze or silicon bronze. Ferroushardware will not be accepted.

3.2 GROUND RODS AND GROUND CABLE:

A. Ground rods shall be driven with a cap driving stud. The ground conductors shall belaid with slack and buried to a minimum depth of 600 mm below grade.

B. All ground cable shall be carefully handled when installed to avoid kinking or cuttingthe conductors. All parts of the grounding system shall be protected againstdamage during construction.

1. Ground conductors shall not be embedded in equipment foundations.

2. Exposed grounding conductors shall follow the contours of the surface overwhich they pass. Diagonal runs shall be avoided. The runs shall be horizontal,vertical and parallel, and securely fastened to the mounting surface withoutslack using galvanized malleable iron straps.

C. Splices and Taps:


16452-3Grounding

System

7/27/2019 16452 Grounding

4/6

1. Conductors shall contain a minimum number of splices throughout each run.Grounding conductors, splices and taps shall be made by the exothermic-weld process. The instructions of manufacturer shall be obtained and followedin welding connections. Particular care shall be taken to use the correct sizeand type of mold and size of cartridge for each combination of conductors.

2. Where a cross connection is required, it shall be made with two T-connectionsspaced not less than 457 mm apart. Connections of cable to ground rod shallalso be exothermic-welded. All ground cables shall be thoroughly cleanedwith wire brush at connections before welding. All welded joints shall bechecked and inspected by the Engineer before being covered. Molds shall notbe used to make more than the maximum number of joints recommended bymanufacturer, or when otherwise unsuitable for further service.

3.3 TERMINAL CONNECTIONS:

A. Connections of ground conductors to conduits shall be made with copper clamps orstraps or by grounding bushings. Ground connections to piping shall generally bewelded or brazed. Non-conductive protective coatings such as paint or enamel onthe conduits or fittings shall be removed from the threads or contacts surfacesbefore attaching grounding connection. After ground connection is attached, anyexposed bare-metal shall be covered again with a coating matching the originalcoating.

3.4 EQUIPMENT GROUNDING:

A. Equipment grounding shall consist of connecting all non-current carrying metallicparts of the electrical mechanical installation to the grounding sources. Comply withSASO 1270, IEC 60364-5-54 or NEC Article 250 for sizes and quantities of

equipment ground conductors, except where larger sizes or more conductors areindicated.

B. Non-current carrying metallic parts of the electrical installation shall include suchitems as metal conduits, raceways, outlet boxes, cabinets, panel board,transformers/switchgear, exposed metal parts of apparatus, and other electricalequipment, protecting or shielding electrical equipment from direct access byunauthorized personnel.

C. The series grounding of one piece of equipment to another will not be permitted. Allequipment grounding connections shall be tapped from the applicableground/source.

D. Ground continuity conductors other than metallic conduits, trunking and cable armorshall consist of a special green colored insulated copper conductor, size as shownon the drawings.

E. Computer and other electronic and communication equipment shall be grounded toan equipment earth which will be run separately to the building ground and will beconnected to the main ground bar.

3.5 GROUNDING OF VARIOUS METAL COMPONENTS

A. Ground all extraneous metalwork such as steel structure, concrete reinforcement,

ducting, piping, suspended ceiling grids, enclosures, doors, grilles, barriers andother metal components of building.


16452-4Grounding

System

7/27/2019 16452 Grounding

5/6

3.6 GROUNDING CONDUCTOR:

A. A separate green-yellow colored insulated grounding conductor shall be installed inall conduits and raceways. Sizes shall be as per SASO 1270, IEC 60364-5-54 or asshown on the drawings

3.7 GROUNDING OF MOTORS:

A. Motors shall be grounded by connecting a green-yellow colored conductor from agrounding bushing in the starter or isolating switch to the motor frame. Theconductor shall be run together with the circuit wiring and terminated in the motorconnection box provided the latter is mechanically connected to the frame. If this isnot feasible, the grounding conductor shall be extended through an insulatedbushed opening in the connection box and connected to the motor base.

3.8 TELECOMMUNICATION GROUNDING

A. All telecommunication rooms shall be interconnected with a complete system ofgrounding wires and grounding busbar including:

1. Telecommunication Main Grounding Busbar (TMGB) for the mainTelecommunication room and entrance room.

2. Telecommunication Busbar (TGB) for every Telecommunication room.

3. Telecommunication Bonding Backbone (TBB) connecting all TMGB andTGB.

4. Bonding conductor to metallic parts and to main electrical grounding busbar.

5. Grounding Equalizer (GE)

a. Minimum size for telecommunication wire in copper 6 mm.

b. Sizing of the telecommunication Bonding Backbone (TBB) shallfollow the TIA/ EIA J-STD-607-A as follows:

TBB Length (mm) TBB Size (mm)4-6 166-8 25

8-10 3510-13 3513-16 5016-20 50Greater than ~20 95

c. All materials of busbar and conductors shall be copper. Conductorcan be insulated with green color.

d. The sizing and drilling of the busbar shall follow the details asindicated in TIA/EIA J-STD-607-A and as shown in the detaildrawing. Busbar shall be factory predrilled.

3.9 TESTING:


16452-5Grounding

System

7/27/2019 16452 Grounding

6/6

A. Contractor shall measure the ground resistance of the ground well of thecompletely driven ground rod at each location before connecting it to the groundgrid. Upon completion of the entire grounding system of the site, including allnecessary connections and backfilling, Contractor shall measure the groundresistance at a location designated by the Engineer.

B. Measurement shall be made with ground tester. All measurements and tests shallbe witnessed by the Engineer. An acceptable grounding resistance shall not bemore than 3 ohm computer equipment and 5 ohms for general building grounding.If test measurements exceed this value, the Contractor shall install and connectadditional ground rods as directed by the Engineer until this value is obtained.

END OF SECTION


16452-6Grounding

System

16452 grounding

Documents