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Grounding Products and SystemsThe National Electrical Safety Code ® (NESC) and IEEE/ANSI C2-1997contain several changes to the grounding requirements of fences fromthe previous editions. This edition requires per Rule 92E:Technical SectionERITECH ® Fence Post and Gate Grounding SpecificationsFences that are required to be grounded by other parts of thiscode shall be designed to limit touch, step and transferredvoltages in accordance with industry practices.NOTE: IEEE Std 80-2000 is one source that may be utilized toprovide guidance in meeting these requirements.The grounding connections shall be made either to the groundingsystem of the enclosed equipment or to a separate ground. (SeeFigures 73, 74 & 75.)Jumper1. Fences shall be grounded at each side of the gate or otheropening. (See Figure 77.)2. Gates shall be bonded to the grounding conductor, jumper offence. (See Figure 77.)3. A buried bonding jumper shall be used to bond across the gateor other opening in the fence, unless a nonconducting fencesection is used. (See Figure 77.)4. If barbed wire strands are used above the fence fabric, thebarbed wire strands shall be bonded to the groundingconductor, jumper or fence. (See Figure 78.)Buried Fence GroundFigure 77.5. When fence posts are of conducting material, the groundingconductor shall be connected to the fence post or posts asrequired with suitable connecting means.6. When fence posts are nonconducting material, a suitablebonding connection shall be made to the fence mesh strandsand the barbed wire strands at each grounding conductorpoint. (See Figure 79.)Tinned Split BoltConnectorFigure 78.A second conductor, although not required by NESC, offers personnelprotection if installed under the gate swing area as shown in Figure77. It is also common practice to connect the ground to all fencecorner posts and to the line posts every 50 feet.® National Electronic Safety Code is a registered trademark of the NationalFire Protection Association.Figure 79.72 Ph: 1-800-677-9089www.erico.com
Grounding Products and SystemsTechnical SectionERITECH ® Signal Reference Grids (SRG) and Grounding for Computer RoomGroundingIntroductionProper grounding and bonding of sensitive electronic systems,including computer installations, requires careful considerationof all frequencies from DC to over 100 megahertz. The NationalElectrical Code (NEC) requirements for fault current and NFPAlightning protection must also be met.The safety grounding system (“green wire”) required by Codedoes not address the special requirements of noise immunity.An additional “grounding” system called the Signal ReferenceGrid (SRG) is needed to assure trouble-free equipmentperformance. There is no conflict between NEC safetyrequirements and the need for an SRG to protect computerdata.The ERITECH Signal Reference Grid (SRG) is a low impedancenetwork of conductors, which establish an equipotential planefor high frequency, low voltage digital signals. Since signalvoltages are low, their sensitivity to transient noise is very high -typically 1 volt for digital systems. In order to minimize theeffects of noise, many computer manufacturers, users andgovernment agencies have detailed specifications regardingcomputer grounding. Welded connections are often specifiedbecause they are the only connections proven to ensure a“noise-free” bond. Normal shock and vibrations can jarmechanical connections, creating electronic noise. This causesrelatively high L di/dt voltages due to a sudden change inconnection impedance. This sudden change can result in pulsesthat can be coupled into the signal circuits. These unwantedsignals can create false data or even cause permanent circuitdamage. Corrosion, dirt and cleaning fluids cannot interferewith the molecular bond of a welded joint.Recommendations on ERITECH Signal Reference Grids are in fullagreement with IEEE Std 1100-1999, IEEE RecommendedPractice for Powering and Grounding Sensitive ElectronicEquipment.SRGs are required because computers are sensitive to noisevoltages that have a broad frequency band. At thesefrequencies:1. Distributed capacitance and mutual inductance cannot beignored. Coupling between adjacent power and data circuitsand ground may introduce noise into data cables. Even nearbylightning strikes can be a real threat to proper operation.2. Radiated fields are usually not a threat with the exception ofnearby transmitters, which may be a serious problem andrequire shielding.3. An effective SRG has a multitude of conductors creating avery low impedance to noise at any frequency.4. Termination must be a constant low impedance over the lifeof the facililty. Welded connections are therefore needed so theground path never changes.5. The multiple paths within the SRG allow noise currents todivide at each crossover, which further reduces voltage drop.Other means of creating a Signal Reference Grid exist. Forexample, brazed copper mesh made of round copper or copperclad wire has been used successfully. Mesh is commonly buriedin the structural floor but it often costs more than flat stripSRGs. Raised floor stringers have been used but they have atendency towards loose connections and low capacitance tocomputer cables. The result is higher impedance and lesspredictable performance.The flat strip SRG is the most functional low-impedance andcost-effective computer grounding system available. Comparedto the cost of equipment or the cost of corrupted information,an ERITECH SRG is the best data insurance you can buy.Ph: 1-800-677-9089www.erico.com73
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IntroductionThe facility electrical
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Grounding PrinciplesSoil Resistivit
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Grounding PrinciplesGround / Earthi
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Ground System ComponentsGrounding C
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Ground System ComponentsERITECH ®
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Ground System ComponentsGround Elec
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Ground System ComponentsGround Rod
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Page 33 and 34: Equipotential BondingEquipotential
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Page 39 and 40: Equipotential BondingERITECH ® Spl
Page 43 and 44: Equipotential BondingAircraft Recep
Page 45 and 46: Equipotential BondingSignal Referen
Page 51 and 52: Equipotential BondingInstallationEq
Page 53 and 54: Equipotential BondingEquipotential
Page 55 and 56: Equipotential BondingTemporary Prot
Page 57 and 58: Equipotential BondingERITECH ® Bon
Page 59 and 60: Equipotential BondingFence Post & G
Page 61 and 62: Equipotential BondingReference Data
Page 63 and 64: Static Grounding and BondingStatic
Page 65 and 66: Static Grounding and BondingERITECH
Page 67 and 68: Static Grounding and BondingStatic
Page 69 and 70: Ground TestingGround Test Equipment
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