telecommunications grounding

7/26/2019 Telecommunications Grounding

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9/10/2014

Telecommunications Grounding and

Bonding Generic

Chandrashekar

Technical Manager (India & SW Asia)


2/24

Purpose and scope of TIA-607-BTIA-607-B grounding is normative

and applies to entire building, not

just data center

TIA-607-B, Generic

Telecommunications

Bonding and

Grounding (Earthing)

for Customer

Premises, is now

approved!

Scopenow

includes

groundingof

ITE


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What is TIA-607-B?

Scope:Specifiesrequirementsforagenerictelecommunicationsbondingandgroundinginfrastructure,andits

interconnectiontoothersystems,forlocationswheretelecommunicationsequipmentwillbeorareinstalled

MajorrevisionofJSTD607A:

IncludesG&Boftelecommunicationsspaces(distributorsandcomputerrooms)

Continuedharmonizationefforts(as

practicable)onterminologyandpracticeswithinternationalstandards

ScopeofTIA607B

TBB

Distributors

ComputerRooms

TGB

TMGB


4/24

Equipment in Cabinets and Racks

Rather

than

relying

ontheacpowercord

groundwire,itis

desirablethat

equipment

begroundedinaverifiable

mannerasdescribedin

thisStandard.

Figure7Exampleofthreemethodstobond

equipmentandrackstoground

TIA-607-B:


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Telecommunications Bonding Backbone (TBB)

PurposeofTBBistoreduce

potentialdifferencesbetweeninterconnected

telecommunicationssystemson

differentfloors

OriginatesatTMGBandextendsthroughoutbuildingusing

telecompathways

ConnectsTGBs

that

exist

ineach

distributor


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6

TIA-607-B TBB sizing


7/24

Conductor sizing isnt only about electrical issues

Size matters!

Standards call for a minimum #6

AWG for mechanical strength

Source: Picture from Internet


8/24

Supplemental bonding grid construction per TIA-607-B

#6AWGroundwireor2widecopperstripsbonded

atintersections

Minimumgriddensityis3

m(10ft)centers

Minimum1/0bondto

TGB/TMGB

Examplesupplementalbondinggrid


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Example SBG construction

Make aisle grounds

convenient to racks

and cabinets

Cross aisle grounds

every 10 feet

Use #6 AWG wireUse pedestal

grounding clamps at

conductor

intersections

Bond to AC powerground through a

local TGB


10/24

TEBC to rack connector TIA-607-BOnly 2-hole mechanical is allowed for this

application. Concerns:

(1) Vibration test was done at one amplitude and

frequency, which is different from what datainstallations experience

(2) No consideration for temperature fluctuation

(3) No consideration for stress relaxation


11/24

Mesh-BN: a collection of components (As per CENELEC documents, includes

TIA-942s Data Center Grounding Infrastructure as the SupplementalBonding Network and IEEE Std 1100 calls the MCBN), per TIA-607-B

Information

technology

equipment(ITE)

Racksand

cabinets

Cabling

pathways

(notshown)

Buildingsteel

Supplemental

bondinggrid

(SBG)

Conduits

Rackbonding

conductor

(RBC)


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Preventing loose busbar connections

12

Two-hole

compression

lugs required

on TGB &

TMGB

(Type LCC-W)

BICSI-607 stainless steel TGB hardware

stack-up (requires locking washer, and

stainless or SiBr hardware)

(Parts HDW1/4-KT, HDW3/8-KT)


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13

BICSI Telecommunications Distributions Methods Manual(12th) on the TGB andTMGB

The same

considerations as are

found in TIA-607-B


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14

ANSI/NECA/BICSI-607-2011 busbars

Panduit

recommendation

on busbar holepatterns: pick a

pattern and stick

with it. Its

confusing to have

multiple holepatterns later.

Recommend using

the BICSI/TIA hole

pattern, as it is well

defined and knownin industry.


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What else needs to be bonded?

IEEEstudieshaveindicatedthatthepointofdiminishingfinancial

returnswithrespecttolightningstrikesis2meters(6feet)

Bondanythingthatcouldbecomechargedthatapersoncould

bumpwhileworkingonarack/cabinetforsafety

Therefore,bondanyconductivepathwithinsixfeetofyourracks/cabinets


16/24

Bond cable tray and ladder rack sections

Split bolts use tin plated if

outdoors (SBC & SBCT,

respectively)

#6 AWG conductor,

green w/yellow jacket OR

Wyr-Grid and GRIDRUNNER

hardware automatically bonds

sections, eliminating the need for

jumper wires

Specify systems that

automatically bond toreduce chances of error


17/24

Remote zone enclosures and TIA-607-B

TIA607B

DistributorsneedTGB/TMGB

ReferencesTIA568C.0fordefinition

TIA568C.0,4.4DistributorsDistributorsprovidealocationforadministration,reconfiguration,connectionof

equipment,andfortesting.Distributorscanbeconfiguredasinterconnectionsorcross

connections

Figure3ofthesamedocumentshowsdistributorsstartingatActiveequipment

MyconclusionIfithasactiveequipment,thenitneedsgrounding

Sizingtheconductor

ATBB,perTIA607B,originatesattheTMGB.ItbondsTGBstotheTMGB(5.2.4)

ATEBCconnectsrackstotheTMGB/TGB(7.1)

TGBislocatedascloseaspracticabletothepanelboard

TheTEBCshallbeacontinuouscopperconductorthatissizednotlessthanaNo.6

AWGorasthelargestsizeequipmentgroundingconductorinheacbranchpowercircuit(s)servingtheracks/cabinetlineup.

17


18/24

Panduit grounding research

Panduitresearchoverthelasttwoyearshasfoundthepresenceofphaseimbalanceon

thetelecommunicationsgroundingsysteminthesteadystate

Frequenciesarepowerlineandthefirstcoupleofharmonics

Observations: High building

steel currents

UPSs are at end

of line-up creating

power imbalancein the ground

conductor

No noticed

network

degradation on thepart of network

operators


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19Episodic/transient research

7MHztransientmeasuredonACEGatCRAH,butnotdetectableatclosestrack

Conclusionsofar:meshbondingandseparatecircuitsfromtheACpanelareeffective

meansofmitigatingissueswithtransients

Flatbraidshavenotbeenshowntoofferatangiblebenefitforthisapplication

TektronixTPS2024

CRAC

Panel

AHSystemsBCP512Probe

(highbandwidth)

Rackbondingconductor


20/24

Grounding rules of thumb for optimum surge suppression

OptimumperformanceofsurgeprotectorsisachievedatfiveOhmsorbelow.Several

manufacturersofelectronicequipmentalsorequirefivetotenOhms asamaximum

resistancefortheirgeartoworkcorrectly.

DitekTechnicalWhitePaper:Grounding101

20


21/24

Twocategoriesoffacility:

1. Minimumrequirements:maintain25throughoutyear,recommendsatleasttwo

electrodes

2. Enhancedrequirementsforcriticalfacilities:designedtohave10orless(and

preferably5orless)

Publicsafetyfacilities

Militaryinstallations

Datacenters

Webhostingfacilities

Centraloffices

Wheretelecommunicationsequipmentisdistributedthroughoutastructure and

may

be

interconnected

by

metallic

links,

the

minimally

required

grounding

system

maynotbeadequate.Facilitieswithadvancedrequirementsordistributed

equipmentwillbenefitfromtheadditionofabuildingperimetergroundloop.

21

TIA-607-B-1 - External Grounding*TR42.16votedtoadoptasnormativeonJune6,2012


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Design specifications, per TIA-607-B-1

Commissionasoilresistivitystudy

Themostcommonmethodofmeasuringaveragesoilresistivityisthefourpointmethod

Requireaseriesofreadingsindifferentlocationstogetabetterideaofthesoilconditions

Require

measurements

of

the

ground

system

resistance

as

verification

of

the

design 3polefallofpotentialmethod(ifroomisavailable,andthegroundisnotconnectedtothe

powersystem)

Clamponmeter

22


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TIA-607-B-1 potential equalization design highlights

23


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Summary

telecommunications grounding

Documents