proper grounding, bonding, lightning & surge ... · pdf filewhyyg ground? • equipment...

Proper Grounding, Bonding, Lightning & Surge ProtectionLightning & Surge Protection

By: Jeff Regan – Telecom Market Manager

ERICO INTERNATIONAL CORPORATION CO O O

WHAT IS GROUNDING AND WHY DO WE DO IT?WHY DO WE DO IT?

GROUNDING (IEEE 100)( )• Definition:

A conducting connection, whether intentional or accidental, by which an electric circuit or equipment is connected to the Earth, or to some conducting body of relatively largethe Earth, or to some conducting body of relatively large extent that serves in place of the Earth.

• Purpose:Used for establishing and maintaining the potential of the Earth (or other conducting body) or approximately that potential on conductors connected to it and for conductingpotential, on conductors connected to it, and for conducting ground current to and from the Earth (or other conducting body).

Step Potentialp

Why ground? y g

• Equipment ProtectionOperate overcurrent device during a groundOperate overcurrent device during a ground

fault.Essential to proper operation of SPDsEssential to proper operation of SPDs

• Noise Control (Computer Grounding)• Lightning Dissipation

Why do we ground?y g

• Required by CODE (NEC Article 250)Required by CODE (NEC Article 250)• Personnel Safety

d i l diff bReduce potential differences between non-current carrying parts (enclosures) and b i dbetween non-current carrying parts and Earth.

SIX POINT PROTECTION PLANPLAN

POINT FOUR

BOND TO CREATE AN EQUIPOTENTIAL GROUND PLANE

What is Bonding? g

• Interconnecting of all Ground Electrode Systemsg yElectrical Grounding SystemLightning Grounding System g t g G ou d g Syste Telecommunications Grounding SystemCable Grounding SystemCable Grounding System

• Connect all conductive objects together both internal and external to the facilityand external to the facility

• Provides near zero voltage difference during ground potential risep

Characteristics of a good ground system

• Must comply with all local and national codes* NEC only contains minimum requirements

• Good electrical conductivityy* Low impedance and resistance

• Resistant to corrosion• Resistant to corrosion* Copper is most commonly used material

• Mechanically robust and reliable* Must perform for life of the facility (40 p y (

years minimum)

Copper vs. Galvanized Rods pp

• Corrosion properties• Corrosion properties• Life expectancy• UL requirements

The Connections

• Often overlooked in grounding system design• Often overlooked in grounding system design• Location and function of connectors• Out of site, out of mind is the general rule• What is the worst type of ground?yp g

Types of Connectors yp• Brazed• Mechanical (compression, bolted, wedge)

Rely on physical pressure to maintain connection• Exothermic Welding

Molecular BondMolecular Bond

HOW DO I LOWER MY RESISTANCE?RESISTANCE?

Add more rods to the Systemy

ilproper rod , 2 x rod length. Minimum 1 x length•o maintain proper rod spacing•o maintain proper rod spacingIdeally, 2 x rod length. Minimum

l h1 x length

Alter The Soil Properties p• Use a ground enhancement material• Bentonite Clayy

Dependent upon moisture. Will wash away.• New IEC 62561-7 GEM ground enhancement material

Hygroscopic, permanent, lower resistivity

Lightning Protection Lightning Protection • Lightning Protection is Necessary! Required?

Examples of Lightning Damagep g g g

Lightning Protection Requirementsg g q• A system that will take a direct

li ht i t iklightning strike• A system that conducts lightning from

the building into the ground• A system that eliminates massive y

structural damage and fire• A system that helps stop theA system that helps stop the

infiltration of lightning along building systemssystems

How Lightning FormsHow Lightning Formso g t g o so g t g o s

E Fields 5-15kV/mE Fields >200kV/m

NFPA780-2000 Grounding/Bonding TechniquesGrounding/Bonding Techniques

• Bond (Ground) Metallic Paths Entering Structure-Bond (Ground) Metallic Paths Entering StructureWater, Gas, Sanitary Sewer, Fire Prot., El. Grnd., Comm. Grd (Telephone, etc.), Process Piping

NFPA780-2000 Grounding/Bonding TechniquesTechniques

Difference of Potential between

grounded building systems andsystems and

the lightning protection system

Current Distribution in non-ideal Faraday CageFaraday Cage

• Lightning ProtectionLightning Protection System - Multiple

Paths

Lightning Protection - Maintenance• System should be checked every two years

ll i i l b bl i l• All air terminals, bases, cables in place• OHM resistance checked on system• New roof-top equipment needs to be added to

systemh k f f h l d• Check structures for signs of physical damage

• Re-roofed? System should be inspected by LP i t ll d/ ULinstaller and/or UL.

• Building additions/attachments needed to be incorporated into lightning protection systemincorporated into lightning protection system.

What killed the Cows?

Copper Theft - A BIG Problem!pp

Lose of Ground Connection!

Stolen Ground Bar

Solutions to TheftERICO’s Solutions to Reduce Copper Theft ERICO offers two types of solutions aimed at minimizing or eliminating theft of

f di t i t l i ticopper from grounding systems in telecommunications.

1) Alternative Conductors to Copper 2) Alternative Ground Bars to Copper

All of the solutions should be complimented with clear signage at the site statingthat the conductors are not copperthat the conductors are not copper. Alternative Conductors to Copper Copper is not substituted easily with other materials because of its uniquepp y qproperties in terms of its conductivity and corrosion. However there are a number of conductorsolutions available that can retain the use of the copper properties but yetchange the composition so that it is of little or no scrap value. The conductorsdiscussed here are well suitable for grounding applications. These newerconductors are also suited for other non-grounding applications. Theft Deterrent Composite Cable. TDCC This is a bare concentric stranded conductor that consists of peripheralThis is a bare concentric stranded conductor that consists of peripheralgalvanized magnetic steel stranding, which protects and conceals the internaltinned copper stands. This conductor is ideal for exposed locations where coppertheft may occur. The conductor is difficult to cut with hand tools, and the outersteel stranding is ferrous, which further deters thieves looking for copper. Copperstranding inside of conductor increases conductivity and conductor flexibility.Copper stranding is tinned for superior corrosion protection

Theft Deterrent Cables

Copper Bonded Steel ConductorsppHigh carbon steel core, low scrap value! Above or below grade usescrap value! Above or below grade use

Ground Bar Replacements -TDSGAp

Alarms sometimes work!

Are You Prepared? p• Lose of ground media to your site can be

d i !devastating!• Do a maintenance check on all ground

systems. Check Ohm readings, visually check for stolen conductors, bars, etc.

• Replace ground systems with Theft Deterrent conductors and assemblies.

• One lightning strike can damage equipment and lose of life: Be Prepared!and lose of life: Be Prepared!

COMMENTS, QUESTIONS?Thank You!

COMMENTS, QUESTIONS?