Earthing Resistance Test Presentation

Copyright © 2008 Lightning Power Surge Protection Sdn Bhd 1

EARTHING

Lightning Power Surge Protection Total Solutions for Mission Critical

Facilities Infrastructure

Presented by,

Ng Jia Wen

Copyright © 2008 Lightning Power Surge Protection Sdn Bhd

Lightning FactsLightning Facts

• Delivers 40,000A of current (some to 100,000A)• Transfers up to 90 Coulombs of charge• Packs 108 to 1010 Volts from cloud to ground• Generates temperatures as high as 50,000°F• Lightning speed approaches one third the speed of light • Travels as far as 40 miles• Can, and does, strike at the same place twice• Causes billions of dollars in property damage annually, many

times resulting in fire and total property loss


Purposes Of GroundingPurposes Of Grounding

• Equipment & personal safety.• Equipment performance.


GROUNDING FOR SAFETYSAFETY

• Limit Voltages Due to:– Lightning– Line Surges– Contact With Higher Voltage Lines

• Stabilize Voltage to Ground• Facilitate OPD Operation During Fault

Ref. NEC Article 250


EFFECTIVE GROUNDINGEFFECTIVE GROUNDING

• Ground Path Must Be:– Permanent and Continuous– Ample Current Capacity– Low Impedance to Facilitate Operation of

Overcurrent Device During Ground Fault


Electrical distribution


STRUCTURAL GROUNDINGSTRUCTURAL GROUNDING


Lightning protection system for commercial/industrial installation


Earthing Resistance Test ResultEarth Resistance TesterMake : Yokogawa (Model: 323S)Serial No. : 62RP0358DescriptionThis tester is a convenient test set to facilitate very easy, accurate measurements of earth resistance. Without a hand-driven generator, this instrument consists of a battery-operated silicon-transistorized DC-AC inverter, an AC potentiometer measuring dial and a galvanometer. Just push the pushbutton switch and move the dial so that the galvanometer shows balanced condition. Then, the resistance is directly read on the dial scale. A wide range of earth resistance of 0 to 1,000 can be measured by a single measuring dial without range changeover. Furthermore, earth voltage can also be measured on the galvanometer scale by positioning the selector.


Front View – No. of Earth Pit


Earthing Resistance Test ResultNo. Tested On: Earth Pit Measured Value (Ω)1. Point 1 0.502. Point 2 0.503. Point 3 0.404. Point 4 0.505. Point 5 0.506. Point 6 3.507. Point 7 0.308. Point 8 0.409. Point 9 0.1010. Point 10 0.1011. Point 11 0.1012. Point 12 0.1013. 415V MSB Earth(Power Earth) 0.10


Yokogawa Earth Resistance Tester Earth Pit

Copper tape continuity is good MSB Earth Bar


Recommendations

• To link Point 6 to Point 5 to achieve lower resistance value.

• Overall building earth, power earth and lightning rods are in healthy condition.

• To install Transient Voltage Surge Suppression (TVSS) protection for computer and office equipments according to the ANSI/IEEE standards.


SYSTEM GROUNDING RESISTANCESYSTEM GROUNDING RESISTANCE GROUND RESISTANCEGROUND RESISTANCE

NEC 25 OHMS SINGLE ELECTRODENEC 25 OHMS SINGLE ELECTRODE( RESIDENTIAL APPLICATIONS )( RESIDENTIAL APPLICATIONS )

1 - 5 OHMS SUITABLE FOR BUILDINGS 1 - 5 OHMS SUITABLE FOR BUILDINGS AND COMMERCIAL INSTALLATIONSAND COMMERCIAL INSTALLATIONS

< 1 OHM FOR INDUSTRIAL < 1 OHM FOR INDUSTRIAL SUBSTATIONSSUBSTATIONS

GROUNDING ELECTRODES SYSTEMSGROUNDING ELECTRODES SYSTEMS

METAL WATER PIPEMETAL WATER PIPE BUILDING STEELBUILDING STEEL DRIVREN RODSDRIVREN RODS


POWERING and GROUNDING POWERING and GROUNDING SENSITIVE ELECTRONIC SENSITIVE ELECTRONIC

EQUIPMENTEQUIPMENT


EMERALD BOOKEMERALD BOOK RECOMMENDED RECOMMENDED

TVSS TVSS STAGED PROTECTIONSTAGED PROTECTION

ATFATF

TELECOMUNICATION LINES PROTECTOR


EMERALD BOOKEMERALD BOOK RECOMMENDED RECOMMENDED

TVSS TVSS STAGED PROTECTIONSTAGED PROTECTION

In addition to Surge Protection Devices (SPDs) installed in the service entrance equipment, it is recommended that additional SPDs of listed Categorgy B or Category A, as specified in IEEE Std C62.41, be applied to downstream electrical switchboards and panelboards, and panelboards on the secondary derived system if they support communications, ITE, signaling, or other form of electronic load equipment.


Thank You

For more informationPlease contact

Ng Jia [email protected]

Earthing Resistance Test Presentation

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