Megger DET20C, DET14C Instruction Manual

DET10C and DET20C Clamp on Ground Resistance Tester

USER MANUAL

NOTICE D’UTILISATION

BEDIENUNGSANLEITUNG

MANUAL DEL USUARIO

G SAFETY WARNINGS

se of rubber gloves is good safety practice even if the equipment is properly operated and

U grounded.

Safety is the responsibility of the operator.

Use extreme caution when using the instrument around energised electrical equipment.

Do not attempt to use the ground tester to twist or pry the ground electrode or ground wire away from the equipment being grounded.

All metal objects or wires connected to the electrical system should be assumed to be lethal until tested, the grounding system is no exception.

Do not drop the ground tester, as damage to the clamp head may occur, producing incorrect readings.

Symbols used on the instrument are:

F Caution: Risk of Electric Shock G Caution: refer to accompanying notes t Equipment protected throughout by Double Insulation (Class II) c IEC 61010-2-032 CAT III 300V, CAT II 600V Pollution Degree 2

CONTENTS

SAFETY WARNINGS 1

FEATURES DESCRIPTION 3

CONTROLS DESCRIPTION 4

LIQUID CRYSTAL DISPLAY 5

OPERATING INSTRUCTIONS 6

Ground Resistance Measurement 6

High and Low Alarm ( ) 8

Ground/Leakage Current Measurement 8

Setting the Sampling Interval 8

Data Logging 8

Downloading Data to a PC (DET20C only) 8

Format of Down Loaded Data (DET20C only) 9

Reading the Data Stored in Memory 9

Clearing the Data Memory 9

Enable RS-232C output (DET20C only) 10

Installation of Megger Download Manager Software 10

Description of Megger Download Manager Software 10

PRINCIPLE OF OPERATION 11

ELECTRICAL SPECIFICATION 13

GENERAL SPECIFICATIONS 14

ACCESSORIES 14

BATTERY REPLACEMENT 15

REPAIR AND WARRANTY 17

FEATURES DESCRIPTION

The clamp-on ground resistance tester enables the user to measure the ground resistance of a ground rod without the use of auxiliary ground rods. The clamp-on ground resistance tester is used in multigrounded systems without disconnecting the ground under test.

CONTROLS DESCRIPTION

1. Jaws Assembly: Encircle electrode or ground rod. No air gap is allowed between the two jaw halves.

2. Hold Button: Maintains last measurement on display

3. Rotary Switch: Power on and function selection.

4. LCD panel

s"button:

5. "REC Function dependant on mode. Starts either data logging, single measurement recording, or data download to PC. Also used to increment a value in conjunction with FUNC button.

6. FUNC button: Press to select "HI" (high alarm), "LO" (low alarm), "SEC" (recording interval), "dL" (Data down load), "no" (Read Data) or "232" (RS-232C)

7. Jaws opening lever

8. Battery cover

9. RS-232C interface connection point (DET20C only)

LIQUID CRYSTAL DISPLAY

1. Function Display current selected function or current record number.

2. Digits Display value from 0 to 9999 with decimal point.

3. Ohm Indicates resistance mode and alarm functions.

4. mA Indicates ground leakage current mode in mA or A

5. Indicates instrument is set at the alarm position.

6. NOISE: Indicates ground resistance tester senses noise or excessive

current present in the ground electrode

7. Jaw Open Displayed if the jaws are opened during the measurement,

this symbol and word OPEN will be shown in LCD.

8. Low Battery Indicates battery voltage is lower than required.

9. NO. Indicates the data record number in memory.

10. REC Indicates data logging is in progress.

11. H Indicates "HOLD" function activated

12. AP Indicates Auto Power Off activated. Deactivate by holding

down the REC button then turning on unit.

OPERATING INSTRUCTIONS

Ground Resistance Measurement

1. Open the jaws and make sure that the mating surfaces are clean and free of dust, dirt or any foreign substance.

2. Snap the jaws a few times to ensure clean contact is made.

3. Turn the rotary switch to the Ω position to power the instrument on. Do not clamp on to any conductor or open the jaws, as this is a self-calibration phase.

4. At power on in _ mode, the instrument will perform a self-calibration for optimum accuracy. Users must wait for self-calibration to be complete before use. During the self-calibration phase, the LCD will show CAL7, CAL6, CAL5, CAL4, CAL 3, CAL2, and CAL1.

5. When the ground tester is ready, a beep will be heard.

6. Place the clamp around the electrode or ground rod to be measured. Operate the jaws a few times for better accuracy.

7. Read the value of Rg (ground resistance) from LCD.

NOTE: For better measurement:

1. Operate the jaws a few times before powering on to clear mating surfaces.

2. Do not clamp on to any conductor during power up (point 3 above).

3. Operate the jaws a few times after clamping around the ground electrode.

NOTE: If self-calibration does not complete (The instrument will continue the process until a successful self-calibration is achieved):

1. Check the jaw mating surfaces. If there is any dirt, dust, or any foreign substance, clean the surfaces.

2. Ensure the jaws are not open during self-calibration.

NOTE: Noise present in the electrode or ground rod. If there is excessive current or over 30V noise in the ground rod, a symbol of "NOISE" will be shown in

LCD. Under these conditions, the reading is no longer accurate. We recommend the current flow is measured before a resistance reading is taken.

NOTE: If jaws are opened during a measurement, a symbol of "OPEN" will be displayed on the LCD.

High and Low Alarm ( )

1. Set the rotary switch to the position.

2. Press the FUNC button to select "HI" or "LO" alarm. The present value of High or Low alarm will be shown in the lower row of the LCD.

3. Press the accelerates. The value can be set from 0 ohm to 1550 ohm and then OL. The value will roll over to 1(HI) or 0 (LO) if the set value in incremented past OL.

4. Once the value is set, press the FUNC button several times until the upper row LCD does not show any letters.

s button to increment the value by 1 ohm. If the button is held down, the rate of increment

5. When the rotary switch is set at the position the instrument will compare the measured value with the high and low values. If the measurement is higher than the HI value, the unit will beep and show "HI --" in the upper row of LCD. If the current measurement is lower than the LO value, the unit will beep and show "LO-- " in the upper row of LCD.

NOTE: If the HI value is set at OL, or the LO value is set at 0, the ALARM function is disabled. The HI or LO value can be disabled individually

NOTE: The HI value cannot be lower than the LO value. Similarly the LO value cannot be higher than the HI value. HI value will be adjusted to LO value plus 1 if roll-over occurs. The maximum value of LO value is HI value minus 1.

NOTE: If data logging is in progress, the beeper will be disabled to save battery power. However, the LCD displays the warning letters of "HI—" or "LO—" if an alarm condition occurs

NOTE: The values for the high and low alarm are stored in the memory. The values will be active when the unit is powered on and alarm mode selected.

Ground/Leakage Current Measurement

1. Set the rotary switch to the mA or A position.

2. Place the clamp around the electrode or ground rod to be measured.

3. Read the value of leakage cur

Setting the Sampling Interval

1. Press the FUNC button until the letters "SEC" are shown on the upper row of LCD.

rent displayed on the LCD.

2. The unit shows the current sampling interval in seconds.

3. Press the increment accelerates. The value can be set from 0 to 255 seconds. The set value will roll over to 0 when the maximum value of 255 seconds is reached.

4. Press the FUNC button several times until the upper row LCD does not show any symbols.

NOTE: The sampling interval is used for data logging and RS-232C output timing.

Data Logging

The unit will start data logging if the "REC s" button is pressed, and the symbol "REC" will be shown on the LCD. Data will be recorded at the specified sampling interval. Data logging will be stopped if the memory is full, or the unit detects a low battery condition, or the "REC s" button is pressed again.

NOTE: With sampling time greater than zero the Auto Power Off feature is disabled in this mode

NOTE: If the sampling interval is set at 0 seconds, one set of data is recorded. To record the next set of data, press the "REC approximately 1 second.

s button to increment the value by 1 second. If the button is held down, the rate of

s" button again. The record number and "REC" symbol is displayed for

Downloading Data to a PC (ASCII format)(DET20C only)

1. Connect the RS-232C cable to the unit and a PC.

2. Run any application software which can accept ASCII data.

3. Press the FUNC button until the symbol "dL" is shown in the upper row on the LCD. The number of records in the memory is shown in the lower row on the LCD.

4. Press the "REC next to the symbol "dL" when data is transferring to PC in ASCII format.

5. The process of down loading can only be halted by turning the instrument off.

6. To exit this function, press the FUNC button several times until the upper row LCD shows no symbols.

NOTE: The unit first sends the sampling time, then the rest of the data stored in memory is sent to the PC.

s" button to down load all the data stored in the memory. The symbol " -- " is shown

Format of Down Loaded Data (DET20C only)

The data is down loaded to the PC in ASCII format. In addition to data readings information includes status of jaws open, noise, HI alarm, LO alarm, and low battery. Below is a list of abbreviations for each

ondition and an example of data down loaded to the PC:

List of abbreviations:

Abbreviation Abbreviation Abbreviation OPEN Jaws open NS Noise HI Hi alarm LO Low alarm HD Data Hold LB Battery low

Example of down loaded data: 0001 (sampling time)

10.00 ohm

10.02 ohm

5.200 ohm LO

1.000 ohm NS

1.500 mA

9.00 A

NOTE: Each record is ended by <CR> and <LF>. The corresponding ASCII codes for <CR> and <LF> are 13 and 10.

Reading the Data Stored in Memory

This function allows users to read the data stored directly from the instrument display.

1. Press the FUNC button until the symbol "NO." is shown on the LCD. The current record number is shown on the upper row of the LCD, the data is shown in the lower row of LCD.

2. Press the

3. Holding down the when the last record is reached.

s button to read the next data record.

s button accelerates the rate of increment. The record number will roll over to 1

Clearing the Data Memory

With the instrument powered down press and hold the FUNC button, then turn the power on. The symbol "CL" will be shown to indicate that memory is cleared.

Enabling the RS-232C output (DET20C only)

To save battery power, the default condition is RS-232C output disabled. To output data to a PC continuously, the RS232C can be enabled by the following procedure.

1. Press the FUNC button until the symbol " 232" is shown on the upper row of LCD.

2. If the RS-232C output is enabled, the symbol "-" will follow the symbol "232". Press the s button to toggle the status of RS-232C output.

3. To exit this function, press the FUNC button several times until the upper row on the LCD is blank.

NOTE: The RS-232C output interval is also specified by the sampling interval. If the sampling interval is set at 0 seconds, data is outputted every 0.5 seconds.

NOTE: The RS-232C output is automatically disabled if "data logging" is in progress.

Installation of Megger Download Manager Software (DET20C)

The DET20C instrument is supplied as standard with Megger Download Manager on CD

1. Hardware and Software Requirements: The requirements are detailed on the rear of the sleeve containing the CD

2. Installation of the Program: Insert the CD. If the CD does not auto-run when inserted in the drive, click on START, RUN, select your CD drive and run START.EXE from the CD. Follow the instructions to install the program to PC.

Description of Megger Download Manager

The Megger Download Manager is a 32-bit Microsoft Windows™ application, which controls data transfer from your DET20C instrument using a specific driver. The driver may be installed from the CD or from our website www.megger.com. Download Manager receives data from the instrument and stores it in comma separated format files that can be viewed and edited with the free C included.

SV Viewer programme

Megger Download Manager features:

1. Single step data download from the DET20C in CSV format

2. Files managed using standard Windows™ format

3. Powerful CSV Viewer included to view, sort, edit, graph and print downloaded data.

4. Compact driver files for quick and easy disk and internet updates

5. Full help facility

NOTE: For operation of the Megger Download Manager refer to the help menu included in the software.

NOTE: Selecting the DET20C driver, then clicking the "Download" button on the tool bar gives the procedure for data download from the instrument

PRINCIPLE OF OPERATION

Below is a simplified typical ground distribution system. The equivalent circuit is shown in Figure A. If R1, R2, R3, ... Rnare simplified to Req, then only Rgand Reqare left in the circuit (refer to Figure B). If a constant voltage is applied to the circuit, the following equation is true.

V=Rg+ R

Where

Req= 1

Σ1

(

and R1, R2, ... Rnare similar values, and n is a large number (such as 200), then Reqwill be much less

If R

than Rgand approaches zero.

)

Ri i = 1, 2, ......, n

Example:

and R1, R2, ... Rnare all 10 Ω, respectively and n = 200. Then Reqby calculation equals

If R

Rg>> Req(Req 0)

eq= 1 = 0.05Ω

+ ... +

10 10 10

= Rg+ Req=10 + 0.05 =10.05 Ω a R

In this example, we can see that as long as the number of multiple electrodes is large enough, the equivalent resistance is negligible with respect to the ground resistance to be measured.

R3.....R

Figure A

.....R

l l l l l l

Figure B

ELECTRICAL SPECIFICATION

Ground Resistance (Auto range):

Range

Resolution Accuracy of Reading

0.025 - 0.250 Ω 0.002 Ω ±1.5% ±0.05 Ω

0.250 - 9.999 Ω 0.02 Ω ±1.5% ±0.1 Ω

10.00 - 99.99 Ω 0.04 Ω ±2.0% ±0.3 Ω

100.0 - 199.9 Ω 0.4 Ω ±3.0% ±1.0 Ω

200.0 - 400.0 Ω 2 Ω ±5.0% ±5 Ω

400.0 - 600.0 Ω 5 Ω ±10% ±10 Ω

600.0 - 1550 Ω 20 Ω ±20%

1. Loop resistance non-inductive, external field <50 A/m, external electrical field <1 V/m, conductor centered in jaws.

2. Resistance Measurement Frequency: 3.333 KHz

High and Low Alarm

Range Resolution

High Alarm 0 - 1550 Ω1 Ω

Lo Alarm 0 - 1550 Ω1 Ω

Ground/Leakage Current

(Auto range, 50/60 Hz, True RMS, Crest Factor <3.5)

Range Resolution Accuracy of Reading

0.200 - 1.000 mA 0.001 mA ±2.0% ±0.05 mA

1.00 - 10.00 mA 0.01 mA ±2.0% ±0.03 mA

10.0 - 100.0 mA 0.1 mA ±2.0% ±0.3 mA

100 - 1000 mA 1 mA ±2.0% ±3 mA

Ground/Leakage Current (50/60 Hz, True RMS, Crest Factor < 3.5)

Range Resolution Accuracy of Reading

0.20 – 35.00 A 0.01 A ±2.0% ±0.03 A

Accuracy of Resistance Calibration Plate: ±

Data Logging Capacity: 8180 records (DET20C), 116 records (DET10C)

Data Logging Interval: 1 to 255 seconds

RS-232C Output: 0.5 and 1 to 255 seconds

GENERAL SPECIFICATIONS

Conductor Size: 35 mm (1.36") Ø approx.

Battery Type: 9V IEC 6 LR61 (Alkaline)

Display Type: 4 digits 9999 counts LCD

Range Selection: Auto

Overload Indication: OL

Power Consumption: 40 mA

Low Battery Indication:

Battery Life:

3000 measurements

Auto Power Down:5 minutes approx.

Sampling Time: 0.5 seconds

Operating Temperature:

0ºC to 50ºC (14ºF to 122ºF)

Operating Humidity: Less than 85% RH

Storage Temperature:

-20ºC to 60ºC (-4ºF to 122ºF)

Storage Humidity: Less than 75% RH

EMC 61326-1

Operational uncertainties: Refer to

www.megger.com

ACCESSORIES

Resistance Calibration Plate x 1 9V Battery (Installed) x 1

Users Manual x 1

Carrying Box x 1

Accessories (DET-20C)

RS-232C Cable

Megger Download Manager CD

Dimensions

276 mm (L) x 100 mm (W) x 47 mm (H)

10.8" (L) x 3.9" (W) x 1.9" (H)

Weight

750g/1.65lbs

BATTERY REPLACEMENT

When the "low battery" symbol is displayed on the LCD, replace the old battery with a new battery.

emove instrument from test piece during battery change.

1. Turn the switch to the OFF position.

2. Unfasten the battery cover screw.

3. Lift and remove the battery cover.

4. Remove the old battery.

5. Install the new 9 V battery.

6. Replace the battery cover and secure the screw.

REPAIR AND WARRANTY

The instrument circuit contains static sensitive devices, and care must be taken in handling the printed

ircuit board. If the protection of an instrument has been impaired it should not be used, and be sent

c for repair by suitably trained and qualified personnel. The protection is likely to be impaired if, for example, the instrument shows visible damage, fails to perform the intended measurements, has been subjected to prolonged storage under unfavourable conditions, or has been exposed to severe transport stresses.

New Instruments are Guaranteed for 1 Year from the Date of Purchase by the User.

Note

: Any unauthorized prior repair or adjustment will automatically invalidate the Warranty.

Instrument Repair and Spare Parts

For service requirements for Megger Instruments contact

Megger Limited or Megger

Archcliffe Road Valley Forge Corporate Center Dover 2621 Van Buren Avenue Kent CT17 9EN Norristown England PA 19403 U.S.A.

Tel: +44 (0)1304 502243 Tel: +1 (610) 676-8579

Fax: +44 (0)1304 207342 Fax: +1 (610) 676-8625

Returning an Instrument for Repair

If returning an instrument to the manufacturer for repair, it should be sent, freight pre-paid, to the appropriate address. A copy of the Invoice and of the packing note should be sent simultaneously by airmail to expedite clearance through Customs. A repair estimate showing freight return and other charges will be submitted to the sender, if required, before work on the instrument commences.

DET10C/DET20C PINCE DE CONTRÔLE DE TERRE

NOTICE D’UTILISATION

G AVERTISSEMENT

Par mesure de sécurité, il est recommandé de porter des gants de caoutchouc, même si les équipements sont correctement utilisés et mis à la terre.

La sécurité reste de la responsabilité de l’opérateur.

Prendre toutes les précautions nécessaires lors de l’utilisation de l’appareil à proximité d’équipements sous tension.

Ne pas utiliser la pince de contrôle pour plier ou arracher l’électrode ou le fil de terre de l’équipement testé.

Tous les objets métalliques ou fils connectés au circuit électrique devront être considérés comme potentiellement dangereux jusqu’à la fin du test. Il en est de même pour le circuit de mise à la terre.

Définition des symboles utilisés

F Attention : risques de chocs électriques G Attention : consulter les documents fournis avec l’appareil t Double isolation c IEC 61010-2-032 CAT III 300V, CAT II 600 V Degré de pollution 2

TABLE DES MATIÈRES

AVERTISSEMENT 19

GÉNÉRALITÉS 21

DESCRIPTION DES CONTRÔLLES 22

AFFICHAGE À CRISTAUX LIQUIDES 23

UTILISATION 24

Mesure de la résistance de terre 24

Alarme haute et alarme basse ( ) 24

Mesure du courant de fuite 26

Réglage de l'intervalle d’échantillonnage 26

Saisie des données 26

Téléchargement des données vers un PC (format ASCII) (DET20C uniquement) 27

Format des données téléchargées (DET20C uniquement) 27

Lecture des données stockées en mémoire 28

Effacement des données en mémoire 28

Activation du transfert RS-232C (DET20C uniquement) 28

Installation du gestionnaire de téléchargement Megger (DET20C) 29

Description du gestionnaire de téléchargement Megger 29

PRINCIPE DE FONCTIONNEMENT 30

CARACTERISTIQUES ÉLECTRIQUES 32

CARACTERISTIQUES GÉNÉRALES 33

ACCESSORIES 33

REMPLACEMENT DE LA PILE 34

RÉPARATION ET GARANTIE 35

GÉNÉRALITÉS

Grâce à cette pince de contrôle, l’utilisateur peut mesurer la résistance d’un piquet de mise à la terre sans utiliser des piquets supplémentaires. Cet appareil est utilisé dans des circuits avec mises à la terre multiples, sans qu’il soit besoin de déconnecter la terre à tester.

DESCRIPTION DES CONTRÔLLES

1. Mâchoires : électrode formant un cercle fermé. Il n’existe aucun entrefer entre les deux moitiés des mâchoires.

2. Touche « Hold »(maintient) : garde la dernière mesure affichée à l’écran.

3. Sélecteur rotatif : allume l’appareil et permet de sélectionner les différentes fonctions.

4. Affichage à cristaux liquides.

5. Touche « REC saisie des données, soit l’enregistrement d’une seule mesure, soit le téléchargement des données vers un PC. Elle permet également d’incrémenter une valeur quand elle est utilisée avec la touche « FUNC » (fonction).

6. Touche « FUNC » (fonction) : appuyer sur cette touche pour sélectionner « HI » (alarme haute), « LO » (alarme basse), « SEC » (intervalle entre deux enregistrements), « dL » (téléchargement des données), « NO » (lecture des données) ou « 232 » (RS-232C).

7. Levier d’ouverture des mâchoires.

8. Couvercle du logement de pile

9. Point de connexion RS-232C (DET20C uniquement).

s » (enregistrement) : cette fonction dépend du mode choisi. Elle déclenche, soit la

AFFICHAGE À CRISTAUX LIQUIDES

1. Fonction : Affiche la fonction sélectionnée ou le numéro de l’enregistrement en cours.

2. Chiffres : Affiche une valeur comprise entre 0 et 9999 avec un point décimal.

3. Ohm : Indique que l’appareil est réglé en mode de mesure de résistance. Indique les

alarmes.

4. mA : Indique que l’appareil est réglé en mode de mesure du courant de fuite en mA

ou A.

5. : Indique que l’appareil est réglé en position d’alarme.

6. NOISE : (Perturbations). Indique que la pince de contrôle détecte des perturbations ou un

courant excessif dans l’électrode de terre.

7. Mâchoires ouvertes : Indique si les mâchoires sont ouvertes lors de la mesure. Ce symbole, ainsi

que le mot « OPEN » (ouvert), s’affichent sur l’écran.

8. Pile faible : Indique que le niveau de charge de la pile est inférieur à celui requis.

9. NO : (numéro). Indique le numéro d’enregistrement des données.

10. REC : (enregistrement). Indique que la saisie des données est en cours.

11. H : Indique que la fonction « HOLD » (maintient) est activée.

12. AP : Indique que la mise à l’arrêt automatique est activée. Pour désactiver cette

fonction, maintenir la touche « REC l’appareil.

s » (enregistrement) pressée et allumer

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