11134-eng-01-a principles. testing methods and applications

8/3/2019 11134-Eng-01-A Principles. Testing Methods and Applications

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Principles,

testing methods

and applications

Earth GroundResistance

Diagnose intermittent

electrical problems

Avoid unnecessarydowntime

Learn earth groundsaety principles


2/16

Why test

grounding systems?

Over time, corrosive soils with high mois-ture content, high salt content, and hightemperatures can degrade ground rods andtheir connections. So although the groundsystem when initially installed, had low earthground resistance values, the resistance o thegrounding system can increase i the groundrods are eaten away.

Grounding testers, like the Fluke 1623 and1625, are indispensable troubleshooting toolsto help you maintain uptime. With rustrating,intermittent electrical problems, the problem

could be related to poor grounding or poorpower quality.

That is why it is highly recommended that allgrounds and ground connections are checkedat least annually as a part o your normal Pre-dictive Maintenance plan. During these periodicchecks, i an increase in resistance o morethan 20 % is measured, the technician shouldinvestigate the source o the problem, andmake the correction to lower the resistance, byreplacing or adding ground rods to the groundsystem.

What is a ground and

what does it do?

The NEC, National Electrical Code, Article 100denes a ground as: a conducting connection,whether intentional or accidental between anelectrical circuit or equipment and the earth, orto some conducting body that serves in place othe earth. When talking about grounding, it isactually two dierent subjects: earth groundingand equipment grounding. Earth grounding is

an intentional connection rom a circuit con-ductor, usually the neutral, to a ground electrodeplaced in the earth. Equipment groundingensures that operating equipment within a

Why Ground, Why Test?

Why ground?

Poor grounding not only contributes tounnecessary downtime, but a lack o goodgrounding is also dangerous and increasesthe risk o equipment ailure.

Without an eective grounding system,we could be exposed to the risk o electricshock, not to mention instrumentation errors,harmonic distortion issues, power actorproblems and a host o possible intermittentdilemmas. I ault currents have no path tothe ground through a properly designed andmaintained grounding system, they will ndunintended paths that could include people.The ollowing organizations have recommen-dations and/or standards or grounding toensure saety:

OSHA (Occupational Saety HealthAdministration)

NFPA (National Fire Protection Association) ANSI/ISA (American National Standards

Institute and Instrument Society o America)

TIA (Telecommunications IndustryAssociation)

IEC ( International Electrotechnical

Commission) CENELEC (European Committee or

Electrotechnical Standardization)

IEEE (Institute o Electrical and ElectronicsEngineers)

However, good grounding isnt only orsaety; it is also used to prevent damage toindustrial plants and equipment. A goodgrounding system wil l improve the reliabilityo equipment and reduce the likelihood odamage due to lightning or ault currents.Billions are lost each year in the workplace

due to electrical res. This does not accountor related litigation costs and loss o per-sonal and corporate productivity.


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structure is properly grounded. These twogrounding systems are required to be kept sepa-rate except or a connection between the two

systems. This prevents dierences in voltagepotential rom a possible fashover rom light-ning strikes. The purpose o a ground besidesthe protection o people, plants and equipmentis to provide a sae path or the dissipationo ault currents, lightning strikes, static dis-charges, EMI and RFI signals and intererence.

What is a good ground

resistance value?

There is a good deal o conusion as to what

constitutes a good ground and what the groundresistance value needs to be. Ideally a groundshould be o zero ohms resistance.

There is not one standard ground resistancethreshold that is recognized by all agencies.However, the NFPA and IEEE have recom-mended a ground resistance value o 5.0 ohmsor less.

The NEC has stated to Make sure that systemimpedance to ground is less than 25 ohmsspecied in NEC 250.56. In acilities with sen-sitive equipment it should be 5.0 ohms or less.

The Telecommunications industry hasoten used 5.0 ohms or less as their value orgrounding and bonding.

The goal in ground resistance is to achievethe lowest ground resistance value possiblethat makes sense economically and physically.

Why Ground?Why Test?

2

Grounding basics

4

Methods o earthground testing

6

Measuringground resistance

12

Table o

contents

3

Why Test? Corrosive soils.

Why Ground? Lightning strikes.

Use the Fluke 1625 to determine thehealth o your earth ground systems.


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Grounding Basics

Components o a

ground electrode

Ground conductor Connection between the ground conductor

and the ground electrode

Ground electrode

Locations o resistances

(a)Thegroundelectrodeanditsconnection

The resistance o the ground electrode andits connection is generally very low. Groundrods are generally made o highly conduc-

tive/low resistance material such as steelor copper.

(b)Thecontactresistanceothesurroundingearthtotheelectrode

The National Institute o Standards (a gov-ernmental agency within the US Dept. oCommerce) has shown this resistance to bealmost negligible provided that the groundelectrode is ree o paint, grease, etc. andthat the ground electrode is in rm contactwith the earth.

(c)Theresistanceothesurrounding

bodyoearthThe ground electrode is surrounded by earthwhich conceptually is made up o concen-tric shells all having the same thickness.Those shells closest to the ground electrodehave the smallest amount o area resultingin the greatest degree o resistance. Eachsubsequent shell incorporates a greater arearesulting in lower resistance. This nallyreaches a point where the additional shellsoer little resistance to the ground surround-ing the ground electrode.

So based on this inormation, we should ocuson ways to reduce the ground resistance wheninstalling grounding systems.

What aects the

grounding resistance?

First, the NEC code (1987, 250-83-3) requires aminimum ground electrode length o 2.5 meters(8.0 eet) to be in contact with soil. But, thereare our variables that aect the ground resis-tance o a ground system:

1. Length/depth o the ground electrode

2. Diameter o the ground electrode

3. Number o ground electrodes

. Ground system design

Length/depthothegroundelectrode

One very eective way o lowering groundresistance is to drive ground electrodes deeper.Soil is not consistent in its resistivity and canbe highly unpredictable. It is critical wheninstalling the ground electrode, that it is belowthe rost line. This is done so that the resistanceto ground will not be greatly infuenced by thereezing o the surrounding soil.

Generally, by doubling the length o theground electrode you can reduce the resistancelevel by an additional 0 %. There are occa-sions where it is physically impossible to drive

ground rods deeperareas that are composed orock, granite, etc. In these instances, alternativemethods including grounding cement are viable.

Diameterothegroundelectrode

Increasing the diameter o the ground electrodehas very little eect in lowering the resistance.For example, you could double the diameter oa ground electrode and your resistance wouldonly decrease by 10 %.


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Numberogroundelectrodes

Another way to lower ground resistance is touse multiple ground electrodes. In this design,more than one electrode is driven into theground and connected in parallel to lower theresistance. For additional electrodes to be eec-tive, the spacing o additional rods need to beat least equal to the depth o the driven rod.Without proper spacing o the ground elec-trodes, their spheres o infuence will intersectand the resistance will not be lowered.

To assist you in installing a ground rod thatwill meet your specic resistance requirements,you can use the table o ground resistances,below. Remember, this is to only be used as a

rule o thumb, because soil is in layers and israrely homogenous. The resistance valueswill vary greatly.

Groundsystemdesign

Simple grounding systems consist o a singleground electrode driven into the ground. Theuse o a single ground electrode is the mostcommon orm o grounding and can be oundoutside your home or place o business. Complexgrounding systems consist o multiple groundrods, connected, mesh or grid networks, ground

plates, and ground loops. These systems aretypically installed at power generating substa-tions, central oces, and cell tower sites.

Complex networks dramatically increase theamount o contact with the surrounding earthand lower ground resistances.

Each ground electrode has its ownsphere o infuence. Ground

systems

Single ground electrode.

Multiple ground electrodesconnected.

Mesh network.

Ground plate.

Typeo soil

Soilresistivity

RE

Earthing resistance

Groundelectrodedepth(meters)

Earthingstrip(meters)

M 3 6 10 5 10 20

Very moist soil,swamplike

30 10 5 3 12 6 3

Farming soil loamyand clay soils

100 33 17 10 0 20 10

Sandy clay soil 150 50 25 15 60 30 15

Moist sandy soil 300 66 33 20 80 0 20

Concrete 1:5 00 - - - 160 80 0

Moist gravel 500 160 80 8 200 100 50

Dry sandy soil 1000 330 165 100 00 200 100

Dry gravel 1000 330 165 100 00 200 100

Stoney soil 30,000 1000 500 300 1200 600 300

Rock 107 - - - - - -

5


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What are the Methods o Earth Ground Testing?

There are our types o earth ground testingmethods available:

SoilResistivity (using stakes)

Fall-o-Potential (using stakes)Selective (using 1 clamp and stakes)Stakeless (using 2 clamps only)

Soil resistivity

measurement

Whydeterminethesoilresistivity?

Soil Resistivity is most necessary when deter-mining the design o the grounding system or

new installations (green eld applications) tomeet your ground resistance requirements.Ideally, you would nd a location with thelowest possible resistance. But as we discussedbeore, poor soil conditions can be overcomewith more elaborate grounding systems.

The soil composition, moisture content, andtemperature all impact the soil resistivity. Soilis rarely homogenous and the resistivity o thesoil will vary geographically and at dierentsoil depths. Moisture content changes season-ally, varies according to the nature o the sublayers o earth, and the depth o the permanent

water table. Since soil and water are generallymore stable at deeper strata, it is recommendedthat the ground rods be placed as deep aspossible into the earth, at the water table ipossible. Also, ground rods should be installedwhere there is a stable temperature, i.e. belowthe rost line.

For a grounding system to be eective, itshould be designed to withstand the worstpossible conditions.

HowdoIcalculatesoilresistivity?

The measuring procedure described below usesthe universally accepted Wenner method devel-oped by Dr. Frank Wenner o the US Bureau oStandards in 1915. (F. Wenner, A Method o Mea-suring Earth Resistivity; Bull, National Bureau oStandards, Bull 12() 258, p. 78-96; 1915/16.)

Theormulaisasollows: = 2 p A R( = the average soil resistivity to depth A in ohmcm)

p = 3.116A = the distance between the electrodes in cmR = the measured resistance value in ohms rom

the test instrument

Note: Divide ohmcentimeters by 100 toconvert to ohmmeters. Just watchyour units.

Example: You have decided to install

three meter long ground rods as part oyour grounding system. To measure thesoil resistivity at a depth o three meters,we discussed a spacing between the testelectrodes o three meters.

To measure the soil resistivity start theFluke 1625 and read the resistance valuein ohms. In this case assume the resis-tance reading is 100 ohms. So, in thiscase we know:

A = 3 meters, and

R = 100 ohmsThen the soil resistivity would equal: = 2 x p x A x R = 2 x 3.116 x 3 meters x 100 ohms = 1885 m


7/16

HowdoImeasuresoilresistance?

To test soil resistivity, connect the ground testeras shown below.

As you can see, our earth ground stakes arepositioned in the soil in a straight line, equidis-tant rom one another. The distance betweenearth ground stakes should be at least threetimes greater than the stake depth. So i thedepth o each ground stake is one oot (.30meters), make sure the distance between stakesis greater than three eet (.91 meters). The Fluke1625 generates a known current through thetwo outer ground stakes and the drop in voltagepotential is measured between the two innerground stakes. Using Ohms Law (V=IR), the

Fluke tester automatically calculates the soilresistance.

Because measurement results are oten dis-torted and invalidated by underground pieceso metal, underground aquiers, etc. additionalmeasurements where the stakes axis areturned 90 degrees is always recommended. Bychanging the depth and distance several times,a prole is produced that can determine a suit-able ground resistance system.

Soil resistivity measurements are oten cor-rupted by the existence o ground currents and

their harmonics. To prevent this rom occurring,the Fluke 1625 uses an Automatic FrequencyControl (AFC) System. This automatically selectsthe testing requency with the least amount onoise enabling you to get a clear reading.

a a a

1/3 a

H/C2

OFF

3 POLE

3 POLE

4 POLE 4 POLE

2 POLE

2POLE4 POLE

S/P2

ES/P1

E/C1

START

TEST

DISPLAY

MENU

CHANGE

ITEM

SELECT

1625 ADVANCED EARTH /GROUND TESTER GEO

E S HES

ACRresistance

Earth/GroundResistance 300 k DC Low Resistance 3k300k

RA RR~

Setup or soil resistivity testingusing the Fluke 1623 or 1625.

7


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Fall-o-Potential

measurement

The Fall-o-Potential test method is used tomeasure the ability o an earth ground system or

an individual electrode to dissipate energy roma site.

HowdoestheFall-o-Potentialtestwork?

First, the earth electrode o interest must bedisconnected rom its connection to the site.Second, the tester is connected to the earthelectrode. Then, or the 3-pole Fall-o-Potentialtest, two earth stakes are placed in the soil ina direct lineaway rom the earth electrode.Normally, spacing o 20 meters (65 eet) is su-

cient. For more detail on placing the stakes, seethe next section.

A known current is generated by the Fluke1625 between the outer stake (auxiliary earthstake) and the earth electrode, while the drop involtage potential is measured between the inner

earth stake and the earth electrode. Using OhmsLaw (V = IR), the tester automatically calculatesthe resistance o the earth electrode.

Connect the ground tester as shown inthe picture. Press START and read out the R

E

(resistance) value. This is the actual value othe ground electrode under test. I this groundelectrode is in parallel or series with otherground rods, the R

Evalue is the total value o

all resistances.

Howdoyouplacethestakes?

To achieve the highest degree o accuracy whenperorming a 3pole ground resistance test,it is essential that the probe is placed outside

the sphere o infuence o the ground electrodeunder test and the auxiliary earth.I you do not get outside the sphere o infu-

ence, the eective areas o resistance willoverlap and invalidate any measurements thatyou are taking. The table is a guide or appro-priately setting the probe (inner stake) andauxiliary ground (outer stake).

To test the accuracy o the results and toensure that the ground stakes are outside thespheres o infuence, reposition the inner stake(probe) 1 meter (3 eet) in either direction andtake a resh measurement. I there is a signi-cant change in the reading (30 %), you needto increase the distance between the groundrod under test, the inner stake (probe) and theouter stake (auxiliary ground) until the measuredvalues remain airly constant when reposi-tioning the inner stake (probe).

>20 m (65 ft) >20 m (65 ft)

H/C2

OFF

3 POLE

3 POLE

4 POLE 4 POLE

2 POLE

2

POLE4 POLE

S/P2

ES/P1

E/C1

START

TEST

DISPLAY

MENU

CHANGE

ITEM

SELECT


E S H

ACRresistance

Earth/GroundResistance 300k DC Low Resistance 3k300k

RA RR~

Innerstake

Outerstake

Earthelectrode

Depthothegroundelectrode

Distancetothe

innerstake

Distancetothe

outerstake

2 m 15 m 25 m

3 m 20 m 30 m

6 m 25 m 0 m

10 m 30 m 50 m


9/16


10/16

H/C2

OFF

3 POLE

3 POLE

4 POLE 4 POLE

2 POLE

2

POLE4POLE

S/P2

ES/P1

E/C1

START

TEST

DISPLAY

MENU

CHANGE

ITEM

SELECT


E S H

ACRresistance


RA RR~

EI-162X

SENSINGCURRENT

TRANSFORMER

EI-162A

C

INDUCING

CURRENT

TRANSFORMER

>10 cm (4 in)


Stakeless measurement

The Fluke 1625 earth ground tester is able to

measure earth ground loop resistances or multi-grounded systems using only current clamps.This test technique eliminates the dangerous,and time consuming activity o disconnectingparallel grounds, as well as the process onding suitable locations or auxiliary groundstakes. You can also perorm earth ground testsin places you have not considered beore: insidebuildings, on power pylons or anywhere youdont have access to soil.

With this test method, two clamps are placedaround the earth ground rod or the connecting

cable and each are connected to the tester.Earth ground stakes are not used at all. Aknown voltage is induced by one clamp, andthe current is measured using the second clamp.The tester automatically determines the groundloop resistance at this ground rod. I there isonly one path to ground, like at many residen-tial situations, the Stakeless method will notprovide an acceptable value and the Fall-o-Potential test method must be used.

The Fluke 1625 works on the principle thatin parallel/multi-grounded systems, the netresistance o all ground paths will be extremely

low as compared to any single path (the oneunder test). So, the net resistance o all theparallel return path resistances is eectivelyzero. Stakeless measurement only measuresindividual ground rod resistances in parallel toearth grounding systems. I the ground systemis not parallel to earth then you will either havean open circuit, or be measuring ground loopresistance.

Source

Measure

OFF

ON

OFF

ON

OFF

ON

OFF

ON

OFF

ON

OFF

ON

OFF

ON

OFF

ON

OFF

ON

H/C2

OFF

3 POLE

3 POLE

4 POLE 4 POLE

2 POLE

2

POLE4 POLE

S/P2

ES/P1

E/C1

START

TEST

DISPLAY

MENU

CHANGE

ITEM

SELECT

1625ADVANCED EARTH /GROUND TESTER GEO

E S H

ACRresistance


RA RR~

E I - 1 6 2 X

SENSING

CURRENT

TRA

NSFORMER

EI-1

62AC

INDU CIN

GC URRE NT

TRA NSFOR MER

Setup or the stakeless method

using the 1625.

Test current paths in the stakeless method.

0


11/16

Groundimpedancemeasurements

When attempting to calculate possible shortcircuit currents in power plants and other highvoltage/current situations, determining the com-plex grounding impedance is important sincethe impedance will be made up o inductiveand capacitive elements. Because inductivityand resistivity are known in most cases, actualimpedance can be determined using a complexcomputation.

Since impedance is requency dependent,the Fluke 1625 uses a 55 Hz signal or thiscalculation to be as close to voltage operatingrequency as possible. This ensures that themeasurement is close to the value at the true

operating requency. Using this eature o theFluke 1625, accurate direct measurement ogrounding impedance is possible.

Power utilities technicians, testing high voltagetransmission lines, are interested in two things.The ground resistance in case o a lightningstrike, and the impedance o the entire systemin case o a short circuit on a specic point in theline. Short circuit in this case, means an activewire breaks loose and touches the metal grid oa tower.

H/C2

OFF

3 POLE

3 POLE

4 POLE 4 POLE

2 POLE

2

POLE4POLE

S/P2

ES/P1

E/C1

START

TEST

DISPLAY

MENU

CHANGE

ITEM

SELECT


SES

ACRresistance


RA RR~

ST

1

Two-polegroundresistance

In situations where the driving o ground stakes is neitherpractical nor possible, the Fluke 1623 and 1625 testersgive you the ability to do two-pole ground resistance/continuity measurements, as shown below.

To perorm this test, the technician must have accessto a good, known ground such as an all metal waterpipe. The water pipe should be extensive enough and bemetallic throughout without any insulating couplings orfanges. Unlike many testers, the Fluke 1623 and 1625

perorm the test with a relatively high current (short circuitcurrent > 250 mA) ensuring stable results.

Equivalent circuit ortwo-point measurement.


12/162

Measuring Ground Resistance

At central ofces

When conducting a grounding audit o a centraloce there are three dierent measurementsrequired.

Beore testing, locate the MGB (Master GroundBar) within the central oce to determine thetype o grounding system that exists. As shownon this page, the MGB will have ground leadsconnecting to the:

MGN (Multi-Grounded Neutral) or incomingservice,

ground eld,

water pipe, and

structural or building steel

First, perorm the Stakeless test on all theindividual grounds coming o o the MGB. Thepurpose is to ensure that all the grounds are

connected, especially the MGN. It is important tonote that you are not measuring the individualresistance, rather the loop resistance o whatyou are clamped around. As shown in Figure 1,connect the Fluke 1625 or 1623 and both theinducing and sensing clamps, which are placedaround each connection to measure the loopresistance o the MGN, the ground eld, thewater pipe, and the building steel.

Second, perorm the 3-pole Fall-o-Potentialtest o the entire ground system, connecting tothe MGB as illustrated on in Figure 2. To get to

remote earth, many phone companies utilizeunused cable pairs going out as much as a mile.Record the measurement and repeat this test atleast annually.

Third, measure the individual resistanceso the ground system using the Selective testo the Fluke 1625 or 1623. Connect the Fluketester, as shown in Figure 3. Measure the resis-tance o the MGN; the value is the resistance othat particular leg o the MGB. Then measurethe ground eld. This reading is the actualresistance value o the central oce groundeld. Now move on to the water pipe, and then

repeat or the resistance o the building steel.You can easily veriy the accuracy o thesemeasurements through Ohms Law. The resis-tance o the individual legs, when calculated,should equal the resistance o the entire systemgiven (allow or reasonable error since allground elements may not be measured).

These test methods provide the most accuratemeasure o a central oce, because it givesyou the individual resistances and their actualbehavior in a ground system. Although accu-rate, the measurements would not show how

the system behaves as a network, because inthe event o a lightning strike or ault current,everything is connected.

MGN

MGB

The layout o a typical central oce.

Water pipe

Groundfeld

Buildingsteel


13/16

Toprovethis,youneedtoperormaewadditionaltestsonindividualresistances.

First, perorm the 3-pole Fall-o-Potentialtest on each leg o the MGB and record eachmeasurement. Using Ohms Law again, thesemeasurements should be equal to the resistanceo the entire system. From the calculations youwill see that you are rom 20 % to 30 % o thetotal R

Evalue.

Finally, measure the resistances o thevarious legs o the MGB using the SelectiveStakeless method. It works like the Stakelessmethod, but it diers in the way we use thetwo separate clamps. We place the inducingvoltage clamp around the cable going to the

MGB, and since the MGB is connected to theincoming power, which is parallel to the earthsystem, we have achieved that requirement.Take the sensing clamp and place it around theground cable leading out to the ground eld.When we measure the resistance, this is theactual resistance o the ground eld, plus theparallel path o the MGB. And because it shouldbe very low ohmically, it should have no realeect on the measured reading. This processcan be repeated or the other legs o the groundbar i.e. water pipe and structural steel.

To measure the MGB via the Stakeless Selec-tive method, place the inducing voltage clamparound the line to the water pipe (since thecopper water pipe should have very low resis-tance) and your reading will be the resistanceor only the MGN.

H/C2

OFF

3 POLE

3 POLE

4 POLE 4 POLE

2 POLE

2POLE4 POLE

S/P2

ES/P1

E/C1

START

TEST

DISPLAY

MENU

CHANGE

ITEM

SELECT


E S H

ACRresistance

Earth/GroundResistance 300k DC Low Resistance 3k300 k

RA RR~

E I - 1 6 2

E

I

C

E

T

T

F

E

MGN

MGB

H/C2

OFF

3POLE

3 POLE

4 POLE 4 POLE

2 POLE

2POLE4 POLE

S/P2

ES/P1

E/C1

START

TEST

DISPLAY

MENU

CHANGE

ITEM

SELECT


E S H

ACRresistance

Earth/GroundResistance 300 k DC Low Resistance 3k300k

RA RR~

EI-162

E

I

C

E

T

T

F

E

MGN

MGB

EI-162AC

I NDUC

I NGCU

RRENT

TRANSFORMER

EI-162X

SENS

I NGCURRENT

TRANSFO

RMER

Figure 1: Stakeless testingo a central oce.

Figure 2: Perormthe 3-PoleFall-o-Potentialtest o the entireground system.

1

H/C2

OFF

3 POLE

3 POLE

4POLE 4POLE

2 POLE

2POLE4POLE

S/P2

ES/P1

E/C1

START

TEST

DISPLAY

MENU

CHANGE

ITEM

SELECT


E S H

ACRresistance


RA RR~

E I - 1 6 2

E

I

C

E

T

T

F

E

MGN

MGB

E I - 1 6 2AC

I N D U C I N G C U R R E N T

T R A N S F O R M E R

Figure 3:Measure theindividualresistances othe groundsystem using theSelective test.


14/16


15/16

For all applications, this is not a true groundresistance measurement because o the networkground. This is mainly a continuity test to veriy

that the site is grounded, that we have an elec-trical connection, and that the system can passcurrent.

3-poleFall-o-Potentialmeasurement

Second, we measure the resistance o the entiresystem via the 3-pole Fall-o-Potential method.Keep in mind the rules or stake setting. Thismeasurement should be recorded and measure-ments should take place at least twice per year.This measurement is the resistance value or theentire site.

Selectivemeasurement

Lastly, we measure the individual grounds withthe Selective test. This will veriy the integrityo the individual grounds, their connections, anddetermine whether the grounding potential isairly uniorm throughout. I any o the measure-ments show a greater degree o variability thanthe other ones, the reason or this should bedetermined. The resistances should be mea-sured on:

Each leg o the tower and all our corners othe building (cell sites/towers)

Individual ground rods and their connections(electrical substations)

Both ends o the remote site (remoteswitching)

All our corners o the building (lightningprotection)

E I - 1

6 2 X

S ENSINGC UR RE NT

T RA NSFORMER

EI-162

AC

I N D U C I N G

C U R R E N T

T R A N S F O R M E R

H/C2

OFF

3 POLE

3 POLE

4 POLE 4 POLE

2 POLE

2POLE4 POLE

S/P2

ES/P1

E/C1

START

TEST

DISPLAY

MENU

CHANGE

ITEM

SELECT


E S H

ACRresistance


RA RR~

I -162X

I

C

T

T

F

E I -1

62X

SE NSINGCURRENT

TR ANSFORMER

H/C2

OFF

3 POLE

3 POLE

4 POLE 4 POLE

2 POLE

2POLE4 POLE

S/P2

ES/P1

E/C1

START

TEST

DISPLAY

MENU

CHANGE

ITEM

SELECT


E S HES

ACRresistance


RA RR~

1

A typical setupat an electricalsubstation.

Using Stakelesstesting at

a remote switch-ing site.

Using Selectivetesting on a light-ning protectionsystem.


16/16

Fluke CorporationPO Box 9090, Everett, WA USA 98206

Fluke Europe B.V.PO Box 1186, 5602 BDEindhoven, The Netherlands

For more information call:In the U.S.A. (800) 3-5853 orFax (25) 6-5116In Europe/M-East/Arica+31 (0) 0 2675 200 orFax +31 (0) 0 2675 222In Canada (800)-36-FLUKE orFax (905) 890-6866From other countries+1 (25) 6-5500 orFax +1 (25) 6-5116

Web access: http://www.luke.com

2006 Fluke Corporation All rights reserved

Fluke.Keeping your worldup and running.

Earth Ground Products

Fluke 1625 Advanced GEOEarth Ground Tester Fluke 1623 Basic GEOEarth Ground Tester

Formoreinormationgotowww.fuke.

Themostcompletetester

The Fluke 1623 and 1625 are distinctive earth ground testersthat can perorm all our types o earth ground measurement:

3-and -pole Fall-o-Potential (using stakes) -pole Soil Resistivity testing (using stakes) Selective testing (using 1 clamp and stakes) Stakeless testing (using 2 clamps only)The complete model kit comes with the Fluke 1623 or 1625

tester, a set o two leads, earth ground stakes, 3 cable reelswith wire, 2 clamps, batteries and manualall inside a ruggedFluke carrying case.

Fluke1625advancedeatures

Advanced eatures o the Fluke 1625 include:

Automatic Frequency Control (AFC)identies existingintererence and chooses a measurement requency to mini-mize its eect, providing more accurate earth ground values

R* Measurementcalculates earth ground impedance with55 Hz to more accurately refect the earth ground resistance

that a ault-to-earth ground would see

Adjustable Limitsor quicker testing

OptionalAccessories

320 mm (12.7 in) Split Core Transormeror perormingSelective testing on individual legs o towers.

The complete kit

eu

11134-eng-01-a principles. testing methods and applications

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