DET Series EARTH GROUND ELECTRODE TESTERS USER GUIDE
Contents
1. 55 10 DL Figure 39 ICLAMP 100 calibration DET4TC DET4TCR ICLAMP DET3TC Press and hold the TEST button until a 100 reading is obtained on the display Switch the instrument OFF using the selector switch The instrument is now calibrated to the ICLAMP and the calibration stored in non volatile memory 56 OPERATION OF THE TWO CLAMP CALIBRATION ADAPTOR Note Ensure the rotary selector switch is in the OFF position Connect the instrument as shown ae VOCLAMP Close the ICLAMP around one loop of the two clamp calibration adaptor Close the VCLAMP around the other loop of the two clamp calibration adaptor Ensure a minimum separation of 100mm between the ICLAMP and VCLAMP Set the rotary selector switch to the LE odi LC Press and release the TEST button by holding the TEST button the resistance measurement will be continually updated The instrument will perform pre measurement checks the status of which will be indicated on the display The two clamp resistance reading will be displayed and should match the value written on the two clamp calibration adaptor Ensure that the ICLAMP and VCLAMP jaw mating surfaces are free of dust and contamination and that they contact completely when the units are closed 57 Currents carried by conductors in close proximity to the ICLAMP may affect calibration and reduce the accuracy of measurements made 58 OPERATION OF THE CALIBRATION A2. G BATTERY INSTALLATION Warning Whenever battery cells are being fitted or replaced there should be no connections to the instrument terminals and the instrument should be switched off Warning To avoid damage by leaking electrolyte or deep discharge do not leave cells fitted in an instrument which will remain unused for extended periods of time Warning Incorrect battery cell polarity can cause electrolyte leakage resulting in damage to the instrument If the battery condition indicator does not show a full charge when battery cells are new a cell may be reversed DET4TCR ONLY Warning Only use the cells recommended by Megger part number 25985 031 G BATTERY CHARGING DET4TCR ONLY Warning Whenever battery cells are being recharged there should be no connections to the instrument terminals and the instrument should be switched off Warning Do not attempt to recharge non rechargeable dry cells in the DET4TCR Doing so will result in instrument damage and may cause personal injury Warning Only use the charging equipment provided by Megger for use with this instrument GENERAL DESCRIPTION The Megger DET family of test instruments offers a unique solution to the measurement of earth or ground electrode rod resistance and soil resistivity The family has six variants supporting 2 3 and 4 wire measurements B The DETSTA provides 2 and 3 wire measurements and offers an analogue display B The DET3TC and DET3TD provide 2
3. Pb E Stakeless measurement o T i ES ES NN NE L ES NN Voltmeter ground noise voltage measurement Current meter MEE S LCD display EE o Backlit display a BEN Moving coil meter EN EE IP54 rated NM HEN EN61010 1 100V CAT IV oe fo Built in battery charger EE BEEN Each instrument kit comprises the following DET instrument Test leads for 3 wire instruments lead lengths are 3m 10m and 15m for 4 wire instruments 3m 10m 10m and 15m Test stakes for 3 wire instruments 2 stakes are supplied for 4 wire instruments 4 stakes are supplied Batteries 8x AA LR6 alkaline except DET4TCR Batteries 8x AA LR6 1800mAhr NiMH DET4TCR only Warranty card Calibration certificate not DET3TA Owners CD ROM manual Tough polypropylene carrying case External AC DC adaptor DET4TCR only PREPARATIONS FOR USE Batteries The Megger DET series instruments are supplied with batteries fitted When batteries become exhausted refer to the section on battery replacement or recharging Warning Do not switch the instrument on with the battery cover removed Inspection Before each use of the instrument visually inspect the instrument case test leads stakes and connectors to confirm that their condition is good with no damaged or broken insulation GENERAL OPERATING INSTRUCTIONS Instrument output voltage selection The maximum output voltage of the instrument is 50 V It is possible to reduce thi
4. 40 80 X 0 D e 100 Q2 V If the P stake resistance is acceptable needle in the green region of the scaleplate release the Rp button Press and hold the TEST button The Rc LED will flash to indicate that the instrument is carrying out pre measurement checks If the Rc LED does not illuminate following the pre measurement checks this indicates that the C stake resistance exceeds the limits for an accurate measurement or that the instrument fuse has ruptured If the Rc LED illuminates solidly following the pre measurement checks this indicates that a three terminal measurement can be made The three terminal resistance reading will be indicated on the scaleplate as shown in Figure 25 40 Figure 25 example three terminal resistance reading Note B No resistance reading is possible if the ground noise voltage exceeds 100 V 41 Three terminal resistance measurement with lead null DET4TD DET4TC and DET4TCR In certain circumstances the resistance of the test lead connecting to the electrode under test may itself form a significant part of the measurement electrode resistance This effect can be eliminated using the lead null technique described in this section 1 Ensure the rotary selector switch is in the OFF position 2 Connect the instrument as shown in Figure 26 Figure 26 instrument connection for measuring three terminal resistance with lead null PT ES M
5. F 0 to 85 RH at 35 C 95 F Storage temperature 20 C to 70 C 4 F to 158 F Dimensions 60mm x 55mm x 25mm 2 5in x 2 25in x lin Weight 0 1 kg approximately 0 2 Ib TWO CLAMP CALIBRATION ADAPTOR ELECTRICAL SPECIFICATION Value 25 Q 196 MECHANICAL SPECIFICATION Operating temperature 10 C to 50 C 14 F to 122 F 0 to 85 RH at 35 C 95 F Storage temperature 20 C to 70 C 4 F to 158 F Dimensions 111mm x 216mm x 45mm 4 4in x 8 5in x 1 8in Weight 0 1 kg approximately 0 2 Ib 63 REPAIR AND WARRANTY The instrument contains static sensitive devices and care must be taken in handling the printed circuit board If an instrument s protection has been impaired it should not be used but sent for repair by suitably trained and qualified personnel The protection is likely to be impaired if for example it shows visible damage fails to perform the intended measurements has been subjected to prolonged storage under unfavourable conditions or has been subjected 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 CALIBRATION REPAIR AND SPARE PARTS For service requirements for Megger Instruments contact Megger Limited or Megger Archcliffe Road Valley Forge Corporate Centre Dover 2621 Van Buren Avenue Kent CT17 9EN Norristo
6. and 3 wire measurements and offer a digital display B The DET4TD DETATC and DET4TCR provide 2 3 and 4 wire measurement and offer a digital display The DET3TC DET4TC and DET4TCR can use an optional current clamp ICLAMP to measure conductor current and electrode rod resistance without disconnection leaving the installation earthing system intact Attached Rod Technique ART Additionally the DET4TC and DET4TCR can drive an optional voltage inducing clamp VCLAMP which in conjunction with the ICLAMP can be used to make stakeless measurements of the earthing system An explanation of the part numbering system is shown in Figure 1 Figure 1 part numbering system y 7 A for analogue display y C for ICLAMP input ART method y D for digital display z for no built in battery charger 3 for 2 and 3 wire measurements z R for built in battery charger 4 for 2 3 and 4 wire measurements Note 1 analogue instrument are only available with 2 and 3 wire measurements 2 allinstruments supporting ART have digital displays The DET family have the following features Feature pubes Automatic C stake check a o NM EEN o E Automatic P stake check Lo E EN NEM t m Manual P stake check os Automatic noise check Lo a EN Manual noise check NM EE S Noise rejection 40 V pk pk o f a 2 wire test EN EE t 3 wire test EN t 4 wire test 2 kQ a wire test 20 kQ J No disconnect testing ART bel
7. change the specification or design without prior notice Megger is a registered trademark Part No DETATC UG en VO2 0207 www megger com
8. connections at rear of instrument 16 DET4TCR Test lead LCD display connections at rear Resistance measurement settings Selector switch Voltage and current measurement settings Test button Backlight control button 25 V 50 V output g voltage select button Ruptured fuse Warning refer to Battery charge Output voltage indicator user manual indicator indicator ART measurement indicator x Possible Not Over under 29V 4 MTT TTT ART possible indicator SOW Hz kO Measuring range V4 p amm y mn y mA Rp Rc V ory m aa s Potential probe Ee Ground noise voltage CUEN poe indi indi K Not OK r istanco indicaldr o OK Not indicator OK Not OK indicator OK Not OK OK Not OK GBEE 7 CIEI z P A cee Test lead connections at rear of instrument 128H 17 BATTERY Battery status indication DET3TC DET3TD DET4TD and DET4TC The battery condition indicator is displayed whilst the instrument is switched on as shown LL napa mmm mum a I liz ILL L 3 LI a aen EM o LI LL Cc Ss NEN E LL LLL p d El E IIl L 3 L 3 cc EL d LL E L 3 a cc 100 battery charge remaining 75 battery charge remaining 50 battery charge remaining 25 battery charge remaining Some charge remaining but in
9. cover must not be opened if the test leads are connected 3 To remove the rear cover release the screw at the bottom of the cover and lift the cover upwards 4 To avoid the possibility of electric shock do not press the TEST button when changing the fuse 5 Remove the ruptured fuse 6 Refit new fuse of the correct type Ys Replace the instrument back cover and secure by tightening the retaining screw 22 DESCRIPTION OF TESTS The description of tests contained within this user guide are instructions for the use of the DET family of instruments by competent persons Suitable applications Where there is doubt about a particular application reference should be made to the advice and guidance contained in the publication Getting Down to Earth which is available from Megger part number 21500 072 The DET range of instruments can be used in agricultural locations as per IEC 61557 5 In these circumstances the output voltage should be switched to 25 V in order to comply with the standard Principle of operation two terminal resistance measurement This technique is used to measure the resistance between two earth points e g between an earth electrode of unknown resistance and a known good ground connection such as metallic underground pipework or building steelwork The DET injects an a c current of known magnitude into the system under test and measures the voltage developed across it as shown in Figure 4 T
10. instrument will display the warning triangle and an over range condition above 20 A no Stakeless testing is possible under this condition B Ensure that the VCLAMP and ICLAMP jaw mating surfaces are free of dust and contamination and that they contact completely when the VCLAMP and ICLAMP are closed B Currents carried by conductors in close proximity to the VCLAMP and ICLAMP may affect calibration and reduce the accuracy of measurements made m Ifthe VCLAMP opens at any time after the TEST button is pressed the test will be aborted 54 ICLAMP calibration DET3TC DET4TC and DET4TCR The ICLAMP should be calibrated once at each test site to take into account the effects of transportation temperature and humidity on the ICLAMP I Ensure the rotary selector switch is in the OFF position Connect the instrument as shown in Figure 38 Ensure that the ICLAMP is not clamped around a conductor Press and hold the TEST button and switch instrument ON to the A setting using the selector switch Release the TEST button Figure 38 ICLAMP zero calibration DET4TC DET4TCR ICLAMP DET3TC Press and hold the TEST button until a 0 reading is obtained on the display Connect the and terminals together using the calibration lead supplied with the ICLAMP X and C terminals for DET3TC Close the ICLAMP around the calibration lead which connects the and 994 terminals as shown in Figure 39 X and C terminals for DET3TC
11. probe Current probe Ground noise voltage resistance indicator resistance OK or indicator OK high OK or high high Test lead connections at rear of instrument 14 DET4TD Test lead connections at rear LCD display Resistance measurement settings 2P 3P and 4P Selector switch Voltage measurement settings Test button Ruptured fuse Warning refer to Over under range _ indicator user manual Battery charge indicator indicator m mA Rone NoiseH Hi Potential probe Cumem IN noise voltage resistance indicator indicator OK high OK or high resistance OK or high Test lead connections at rear of instrument 15 DET4TC LCD displa Test lead pray connections at rear Resistance measurement settings Selector switch Voltage and current measurement settings Test button 25 V 50 V output Backlight control voltage select button button Ruptured fuse Warning refer to Output voltage user manual Battery charge a indicator indicator x Pd indicator Over under range 29V 722822211 v ART measurement dili Illi A T X indicator Possible Not m Measuring range mA indicator 50V possible Z v v cY x IL LR x x I l x x Potential probe Current probe Ground noise voltage Clamp resistance indicator resistance OK Not indicator OK Not OK current presence OK Not OK OK indicator OK Not OK ae 3 Pena A Test lead
12. the assessments show that the risk is significant then the use of fused test leads may be appropriate G LIVE EARTH SAFETY PRECAUTIONS A Live earth is one that carries current from the mains supply or could do so under fault conditions The following warnings apply in addition to those listed previously B All persons involved must be trained and competent in isolation and safety procedures for the system to be worked on They must be clearly instructed not to touch the earth electrode test stakes test leads or their terminations if any Live earths may be encountered It is recommended that they wear appropriate rubber gloves rubber soled shoes and stand on a rubber mat B The earth electrode under test should be isolated from the circuit it is protecting before testing commences If this is not possible ART may be used to measure electrode resistance B The instrument terminals should be connected to the system under test through isolation switches that are rated to handle the likely maximum fault voltages and currents that could be encountered at the installation The isolation switch must be open whilst any personal contact is made with the remote test stakes or the connecting leads e g when changing their position B The instrument terminals should be connected to the system under test through fuses that are rated to handle the likely maximum fault voltages and currents that could be encountered at the installation
13. to operate the instrument whilst the external AC DC adaptor is connected Warning Do not attempt to recharge non rechargeable dry cells in the DET4TCR Doing so will result in instrument damage and may cause personal injury Only use the cells recommended by Megger Warning Only use the external charging equipment provided by Megger 1 To avoid the possibility of electric shock switch instrument OFF and disconnect the instrument from any electrical circuits 2 Move the slide on the terminal panel until the external AC DC adaptor socket is exposed 19 3 Remove the bung from the AC DC adaptor socket 4 Connect the AC DC adaptor and switch on 5 The charging cycle will commence and last approximately 15 5 hours Follow the progress using the charge status LED as shown in Figure 3 NOTE The instrument ambient temperature should be between 10 C 50 F and 40 C 105 F during the charging cycle Figure 3 charge status LED progression Battery charging complete Battery charging in progress Defective non rechargeable cells detected or no batteries present Defective non rechargeable cells detected or no batteries present Charging terminated NaI Battery type DET3TA DET3TC DET3TD DET4TD DET4TC 8x AA LRO 1 5V Alkaline Megger part number 25511 841 DET4TCR 8 x AA LR6 1 2V NiMH 1800mAhr Megger part number 25985 031 Battery replacement Battery replacement Warning Do not operate ins
14. AX 100V CAT IV N ai N d E X Y Electrode under test Current stake 5 Potential stake DET4TD Electrode A DET4TC Potential stake DETATCR 3 Set the rotary selector switch to the position 4 Select the desired test voltage using the P RAVEIUBM button 5 Press and release the TEST button by holding the TEST button the resistance measurement will be continually updated 42 Note The instrument will perform pre measurement check the status of which will be indicated on the display The three terminal resistance with lead null reading will be displayed as shown in Figure 27 Figure 27 example three terminal resistance with lead null reading DET4TC DET4TCR display shown 90V The instrument will display the warning triangle and an excessive noise voltage indicator if the ground noise voltage is above 40 V pk pk 14 Vrms The instrument will display the warning triangle and a voltage over range condition if the ground noise voltage is above 100 V no resistance reading is possible under this condition 43 Four terminal resistivity measurement DET4TD DET4TC and DET4TCR The DET4TD DET4TC and DET4TCR can be used to make soil resistivity measurements The resistivity value can be derived from the four terminal resistance reading made by the instrument and the particular separation and depth of the stakes 1 Ensure the rotary selector switch is in the OFF position 2 Con
15. DAPTOR 1 Ensure the rotary selector switch is in the OFF position 2 Connect the instrument as shown d J P LI s E i 128hz CALIBRATION ADAPTOR 2s Set the rotary selector switch to the PN or E34 position 4 Press and release the TEST button by holding the TEST button the resistance measurement will be continually updated 5 The instrument will perform pre measurement checks the status of which will be indicated on the display 6 The resistance reading will be displayed and should match the value written on the calibration adaptor 59 PREVENTIVE INSTRUMENT MAINTENANCE L The DET series instruments require very little maintenance Test leads should be checked before use to ensure there is no damage Ensure batteries are removed if left unused for extended periods When necessary the instrument can be cleaned with a damp cloth Do not use alcohol based cleaners as these may leave a residue 60 TECHNICAL SPECIFICATION DET3Tx amp DET4Tx General Specification Only values with tolerance or limits are guaranteed data Parameters without tolerances are for information only Ingress protection IP54 C stake P stake and Noise check Automatic Noise rejection 40 V pk to pk 14 V rms 2 wire 3 wire 4 wire test Yes no shorting links required No disconnect testing ART Yes with ICLAMP Stakeless measurement Yes with ICLAMP and VCLAMP Instrum
16. DET Series EARTH GROUND ELECTRODE TESTERS USER GUIDE CONTENTS CONTENTS 2 INTRODUCTION 3 G SAFETY WARNINGS 4 G LIVE EARTH SAFETY PRECAUTIONS 5 G BATTERY INSTALLATION 5 G BATTERY CHARGING DET4TCR ONLY 5 GENERAL DESCRIPTION 6 PREPARATIONS FOR USE 9 GENERAL OPERATING INSTRUCTIONS 10 INSTRUMENT ILLUSTRATIONS 12 BATTERY 18 DESCRIPTION OF TESTS 23 PREVENTIVE INSTRUMENT MAINTENANCE 60 TECHNICAL SPECIFICATION 61 REPAIR AND WARRANTY 64 Symbols used on the instrument are Caution refer to accompanying notes Equipment protected throughout by Double Insulation Class ID Equipment complies with current EU directives Equipment complies with C tick requirements IX Q 7 Do not dispose of in normal waste stream Note The safety warnings provided in this document are indicative of safe practice and shall not be considered exhaustive Additionally they are not intended to replace local safety procedures where the instrument is being used Note This user guide uses the terms earth and ground interchangeably INTRODUCTION Thank you for purchasing the Megger Earth Ground Tester For your own safety and to get the maximum benefit from your instrument please ensure that you read and understand the following safety warnings and instructions before attempting to use the instruments This user manual describes the operation and functions of the DET series of Earth Ground Testers B DET3ZTA B DET3ZTC B DET3TD B
17. DET4TD B DET4TC B DET4TCR B ICLAMP B VCLAMP B CALIBRATION ADAPTOR B TWO CLAMP CALIBRATION ADAPTOR These instruments are designed and manufactured by Megger Limited Archcliffe Road Dover Kent CT17 9EN England Megger Limited reserves the right to change the specification of these instruments at any time without prior notice G SAFETY WARNINGS Safety Warnings and Precautions must be read and understood before the instrument is used They must be observed during use Do not leave the instrument connected to the system under test when not in use Do not touch circuit connections and exposed metalwork of an installation or equipment under test Do not touch the earth stakes test leads and their terminations including connections to the earthing system under test if an installation earth fault can arise unless adequate precautions are taken Do not touch the earth stakes test leads and their terminations including connections to the earthing system under test while the instrument is switched on Do not operate the instrument or connect it to any external system if it shows any visible signs of damage or if it has been stored for prolonged periods in unfavourable conditions Do not operate the instrument or connect it to any external system if the battery compartment or casing is open or any parts of the case including keypad selector switch display window etc are missing Special precautions are n
18. TC DET3TD DETATD DET4TC and DETATCR 1 Ensure the rotary selector switch is in the OFF position 2 Connect the instrument as shown in Figure 14 Figure 14 instrument connection for measuring two terminal resistance Metallic interconect V4 Electrode under test DET3TD Metallic interconnect Va Electrode under test DET4TD 31 Metallic interconnect Va Electrode under test DET3TC Metallic interconnect DET4TC heen tee DET4TCR Set the rotary selector switch to the position Select the desired test voltage using the MEMMBIQ button Press and release the TEST button by holding the TEST button the resistance measurement will be continually updated The instrument will perform pre measurement check the status of which will be indicated on the display The two terminal resistance reading will be displayed as shown in Figure 15 32 Figure 15 example two terminal resistance reading DET4TC DET4TCR display shown 90V Q Note The test voltage used to make the two terminal resistance reading is a c and may not be suitable for continuity testing according to some local regulations The instrument will display the warning triangle and an excessive noise voltage indicator if the ground noise voltage is above 40 V pk pk 14 Vrms The instrument will display the warning triangle and a voltage over range condition if the ground noise voltage is above 100 V no resist
19. a reading of the entire earthing network not just the individual electrode By using a current transducer the Megger ICLAMP to measure the current flowing through the electrode under test as a fraction of the total test current injected the instrument can determine the individual resistance This arrangement is shown in Figure 7 Figure 7 schematic for three terminal resistance measurement using ART without lead null Connection to rest of system g QD ICLAMP SO i H e Earth electrode under test B Potential stake Current stake In this configuration the injected test current I splits along two paths into I1 flowing into the connected earthing system and I2 flowing into the electrode under test i e I I1 I2 The resistance 25 of the electrode under test is calculated as R V I2 or R V C I1 The current transducer CLAMP measures I2 and feeds this value back to the instrument Principle of operation two clamp stakeless resistance measurement In this example the electrode under test is connected to a network of other electrodes It is either impractical or unsafe to disconnect an individual electrode for testing Also there might be insufficient space to perform a classic three terminal resistance measurement The stakeless test method using both VCLAMP and ICLAMP can be used to obtain a measurement for the e
20. ance reading is possible under these conditions 33 Two terminal resistance measurement DET3TA 1 Ensure the rotary selector switch is in the OFF position 2 Select the desired test voltage using the procedure in the section on General Operating Instructions 2s Connect the instrument as shown in Figure 16 Figure 16 instrument connection for measuring two terminal resistance Metallic interconnect 7 7 Electrode under test 4 Set the rotary selector switch to the position 5 The ground noise voltage will be indicated on the scale plate as shown in Figure 17 Figure 17 ground noise voltage indication 6 If the ground noise voltage is less than 40 V pk pk 14 V rms press and hold the TEST button Testing will be inhibited if the ground noise voltage exceeds 40 V pk pk js The Rc LED will flash to indicate that the instrument is carrying out pre measurement checks 34 8 If the Rc LED does not illuminate following the pre measurement checks this indicates that the instrument fuse has ruptured 9 If the Rc LED illuminates solidly following the pre measurement checks this indicates that a two terminal measurement can be made 10 The two terminal resistance reading will be indicated on the scaleplate as shown in Figure 18 Figure 18 example two terminal resistance reading Note B The test voltage used to make the two terminal resistance reading is a c and may not be suitable for continuit
21. easurement range 1 mA to 1200 A Transformation ratio 1000 1 Output signal 1 mA A 1 A 1000 A Accuracy 1mA to 100 mA 3 of reading 0 1 A to 1 A lt 2 of reading 1 Ato 10 A lt 1 of reading 10 A to 100 A 0 5 of reading Operating temperature 10 C to 50 C 14 F to 122 F 0 to 85 RH at 35 C 95 F Storage temperature 20 C to 70 C 4 F to 158 F Jaw opening 57 mm maximum 2 3 in Maximum conductor size 52 mm 2 1 in Insulation Double insulation Voltage rating 600 V CAT III Current rating 1200 A for 20 minutes Ingress protection IP40 Safety EN61010 2 032 EMC EN 50081 1 Class B EN 50082 2 Dimensions 111 mm x 216 mm x 45 mm 4 4 in x 8 5 in x 1 8 in Weight 0 5 kg approximately 1 21b VCLAMP SPECIFICATIONS Insulation Double insulation Voltage rating 600V CAT III Current rating 1200A for 20 minutes Ingress protection IP40 Operating temperature 10 C to 50 C 14 F to 122 F 0 to 85 RH at 35 C 95 F Storage temperature 20 C to 70 C 4 F to 158 F Jaw opening 5 mm maximum 2 3in Maximum conductor size 52mm 2 1in Electrical safety EN61010 2 032 EMC EN 50081 1 Class B EN 50082 2 Dimensions 111mm x 216mm x 45mm 4 4in x 8 5in x 1 8in Weight 0 5 kg approximately 1 2 Ib 62 CALIBRATION ADAPTOR ELECTRICAL SPECIFICATION Value 25 Q 0 1 MECHANICAL SPECIFICATION Operating temperature 10 C to 50 C 14 F to 122
22. ecessary when operating in situations where live earths may be encountered isolation switches and fuses not supplied with this instrument must be used Special precautions are necessary when working near high tension systems MV and HV rubber gloves and shoes not supplied with this instrument should be worn Special precautions are necessary when working in wet conditions or in agricultural areas observe the local safety standards and take all necessary special precautions applicable to the particular location and do not touch the test leads with bare hands Always disconnect the instrument from the earthing system under test while batteries are being changed or the fuse replaced Always replace batteries and fuses with parts of the correct type and rating Do not replace the rechargeable cells in the DET4TCR with non rechargeable dry cells Do not use any other charging equipment other than that supplied by Megger for use with the DET4TCR Do not operate the charging equipment supplied with the DET4TCR in damp or wet environments or outside NOTE THE INSTRUMENT MUST ONLY BE USED BY SUITABLY TRAINED AND COMPETENT PERSONS Users of this equipment and or their employers are reminded that National Health and Safety Legislation requires them to carry out valid risk assessments of all electrical work so as to identify potential sources of electrical danger and risk of electrical injury such as inadvertent short circuits Where
23. ent output Voltage 25 V or 50 V at 128Hz Current 4 5 mA or 0 4 5mA Ground current range with clamp 0 5 mA to 19 9 A Ground current accuracy 5 3 digits Ground voltage range 0 to 100 Vac Ground voltage accuracy 296 ZV Resistance range 0 01 Q to 20 kQ DET4TC and DET4TCR 0 01 Q to 2 KQ all other DET s Resistance accuracy 2P measurements 2 3 digits 3P measurements 2 3 digits 4P measurements 2 3 digits ART measurements 5 3 digits Stakeless measurements 7 3 digits Maximum probe resistance Rp limit 100 kQ 5 0 V output voltage Rc limit 100 kQ 50 V output voltage Limits reduced to 50 kQ for 25 V output voltage Limits reduced to 5 KQ for 0 01 Q resolution Display 315 digit high contrast liquid crystal backlit Battery type DET4TC 8 off AA LR6 dry cells DET4TCR 8 off AA LR6 NiMH rechargeable cells Operating temperature range 15 C to 55 C 5 F to 131 F Storage temperature range 40 C to 70 C 40 F to 158 F Safety Complies with the requirements of EN61010 1 100V CAT IV between terminal pairs EMC In accordance with IEC61326 including amendment No 1 Standards compliance Complies with the requirements of KEMA K85B Complies with the following parts of EN61557 Part 1 General requirements Part 5 Resistance to earth Dimensions 203mm x 148mm x 78mm 8in x 5 8in x 3in Weight Lke 72 2 Ib 61 ICLAMP SPECIFICATIONS M
24. g ground current 100V CAT IV Installation o gt earthing CLAMP conductor Electrode DET3TC under test ee M 128Hz Installation earthing conductor Electrode DETATCR under test DET4TC 3 Close the ICLAMP around the conductor under test 4 Set the rotary selector switch to the A position S The ground current flowing in the conductor will be displayed as shown in Figure 31 46 Figure 31 example ground current reading DET4TC DET4TCR display shown Note B The instrument will display the warning triangle above 2 A no ART testing is possible under this condition B The instrument will display the warning triangle and an over range condition above 20 A no ART testing is possible under this condition 47 Three terminal resistance measurement using ART DET3TC DET4TC and DET4TCR Before making a measurement using ART please follow the procedure contained in the section on ICLAMP calibration 1 Ensure the rotary selector switch is in the OFF position 2 Connect the instrument as shown in Figure 32 Figure 32 instrument connection for measuring three terminal resistance using ART Electrode under test Current stake A Potential stake DET3TC Electrode under test Current stake 5 l DET4TC Potential stake DET4TCR Close the ICLAMP around the conductor under test Set the rotary selector switch to the icition Press and release the TEST button by
25. gure 36 Figure 36 instrument connection for two clamp stakeless measurement NCLAMP foe ICLAMP Electrode DET4TC under test DET4TCR oF Close the ICLAMP around the conductor under test Ensure the arrow on the side of the jaw is pointing in the same direction as the arrow on the VCLAMP 4 Close the VCLAMP around the conductor under test Ensure the arrow on the side of the jaw is pointing in the same direction as the arrow on the ICLAMP 5 Ensure a minimum separation of 100mm between the ICLAMP and VCLAMP 6 Set the rotary selector switch to the Lak os p Press and release the TEST button by holding the TEST button the resistance measurement will be continually updated 8 The instrument will perform pre measurement checks the status of which will be indicated on the display 9 The stakeless resistance reading will be displayed as shown in Figure 37 53 Figure 37 example resistance reading using two clamp stakeless method 10 Under certain circumstances the instrument may display a noise warning as shown This means that interference has been detected which may impair the accuracy of the measurement In particular the reading could be lower than the actual resistance The resistance of the electrode or system must be verified by an alternative method Note B The instrument will display the warning triangle above 2 A no Stakeless testing is possible under this condition B The
26. he system resistance is a simple ratio as per Ohm s Law i e R VA Figure 4 schematic for two terminal resistance measurement C1 E X b I P2 P S P1 ES CO C2 C H Ly Second earth electrode or other low resistance conductive connection to Earth Earth electrode under test E The DET instruments automatically link the C1 P1 and P2 terminals when a two terminal test is selected 23 Principle of operation three terminal resistance measurement The classic fall of potential test is used to accurately measure the resistance of an earth electrode using auxiliary stakes driven into the soil which form a circuit for the test current injection and voltage measurement as used for the two terminal method The DET injects an a c current of known magnitude into the system under test and measures the voltage developed across it as shown in Figure 5 The system resistance is a simple ratio as per Ohm s Law In this case the potential stake is moved by fixed increments in a straight line between the electrode under test and the current stake At each location the resistance is calculated as R V I A graph of resistance versus potential stake position is plotted and the resistance of the electrode under test is taken to be the point at which the curve is flattest Empirical testing has shown that with suitably positioned stakes this method can be shortened by placing the potential stake at a di
27. holding the TEST button the resistance measurement will be continually updated 48 6 The instrument will perform pre measurement checks the status of which will be indicated on the display s The three terminal resistance reading using ART will be displayed as shown in Figure 33 Figure 33 example three terminal resistance reading using ART DETATC DET4TCR display shown 2 Rp Rc VU mm ond 8 Under certain circumstances the instrument may display a noise warning as shown This means that interference has been detected which may impair the accuracy of the measurement In particular the reading could be lower than the actual resistance The resistance of the electrode or system must be verified by an alternative method Note B The instrument will display the warning triangle and an excessive noise voltage indicator if the ground noise voltage is above 40 V pk pk 14 Vrms B The instrument will display the warning triangle and a voltage over range condition if the ground noise voltage is above 100 V no resistance reading is possible under this condition B The instrument will display the warning triangle above 2 A no ART testing is possible under this condition 49 The instrument will display the warning triangle and an over range condition above 20 A no ART testing is possible under this condition Ensure that the ICLAMP jaw mating surfaces are free of dust and contaminati
28. iangle and a voltage over range condition if the ground noise voltage is above 100 V no resistance reading is possible under this condition 38 Three terminal resistance measurement DET3TA 1 Ensure the rotary selector switch is in the OFF position 2 Select the desired test voltage using the procedure in the section on General Operating Instructions 3 Connect the instrument as shown in Figure 21 Figure 21 instrument connection for measuring three terminal resistance Electrode under test Current stake 5 Potential stake 4 Set the rotary selector switch to the position 5 The ground noise voltage will be indicated on the scaleplate as shown in Figure 22 Figure 22 ground noise voltage indication 25 10 100 60 E 0 1 80 K 50 S 100 6 If the ground noise voltage is less than 40Vpk pk 14Vrms press and hold the iq button Testing will be inhibited if the ground noise voltage exceeds 40Vpk pk e The P stake resistance will be indicated on the scaleplate the needle will move into the green region Figure 22 if the P stake resistance is within limits for an accurate measurement and into the red region Figure 24 if the P stake resistance exceeds the limits for an accurate measurement 39 10 LL 12 13 Figure 23 P stake resistance OK green region 25 10 100 60 Figure 24 P stake resistance not OK red region 100 25 10 1 60
29. instrument freight paid to Megger Copies of the original purchase invoice and packing note should be sent simultaneously by airmail to expedite clearance through customs In the case of instruments requiring repair outside the warranty period an immediate quotation can be provided when obtaining the RA number gt You may track the progress of your return on line at www megger com Approved Service Centres A list of Approved Service Centres may be obtained from the UK address above or from Megger s website at www megger com 64 Megger Limited Archcliffe Road Dover Kent CT17 9EN England T 44 0 1 304 502101 F 44 0 1 304 207342 E uksales megger com Megger 4271 Bronze Way Dallas Texas 75237 1019 USA T 1 800 723 2861 USA ONLY T 1 214 333 3201 F 1214 331 7399 E ussales megger com Megger Z A Du Buisson de la Couldre 23 rue Eug ne Henaff 78190 TRAPPES France T 33 0 1 30 16 08 90 F 33 0 1 34 61 23 77 E infos megger com Megger Pty Limited Unit 26 9 Hudson Avenue Castle Hill Sydney NSW 2125 Australia T 61 0 2 9659 2005 F 61 0 2 9659 2201 E ausalesemegger com Megger Limited 110 Milner Avenue Unit 1 Scarborough Ontario M1S 3R2 Canada T 1416 298 9688 Canada only T 1416 298 6770 F 1416 298 0848 E casalesemegger com Megger products are distributed in 146 countries worldwide This instrument is manufactured in the United Kingdom The company reserves the right to
30. l using ART DET4TC DET4TCR display shown This means that interference has been detected which may impair the accuracy of the measurement In particular the reading could be lower than the actual resistance The resistance of the electrode or system must be verified by an alternative method Note B The instrument will display the warning triangle and an excessive noise voltage indicator if the ground noise voltage is above 40 V pk pk 14 Vrms B The instrument will display the warning triangle and a voltage over range condition if the ground noise voltage is above 100 V no resistance reading is possible under this condition B The instrument will display the warning triangle above 2 A no ART testing is possible under this condition B The instrument will display the warning triangle and an over range condition above 20 A no ART testing is possible under this condition B Ensure that the ICLAMP jaw mating surfaces are free of dust and contamination and that they contact completely when the ICLAMP is closed B Currents carried by conductors in close proximity to the ICLAMP may affect calibration and reduce the accuracy of measurements made 52 Two clamp stakeless measurement DET4TC and DET4TCR Before making a stakeless measurement please follow the procedures contained in the sections on ICLAMP calibration 1 Ensure the rotary selector switch is in the OFF position 2 Connect the instrument as shown in Fi
31. lectrode under test A defined test voltage is injected into the system using the VCLAMP inducing a current I to flow and be measured by the ICLAMP The model shown in Figure 8 can be simplified to the resistance of the electrode under test Rx and the resistance of the other electrodes in parallel i e R1 R2 Rn Therefore the current induced by the test voltage is I V R R R R It follows that as the resistance of the other electrodes in parallel approaches zero then the resistance measured approaches the value of the electrode under test Figure 8 schematic for two clamp stakeless resistance measurement Connection to rest of system Earth electrode under test 26 Principle of operation four terminal resistivity measurement The soil resitivity measurement works on a similar principle to the other measurements which use stakes a current is injected around an outer loop and a voltage measured shown in Figure 9 In this case however the measurement made by the instrument requires further conversion using a formula to derive the volumetric soil resistivity from the resistance value display Figure 9 schematic for 4 terminal resistivity measurement For this test the relative spacing and depth of the stakes is important When configured as shown in Figure 9 the soil resistivity can be calculated from the resistance value R displayed on the instrument asp 2xaxAxR 2 Measure
32. ment of ground noise voltage DET3TC DET3TD DET4TD DET4TC and DET4TCR 1 Ensure the rotary selector switch is in the OFF position 2 Connect the instrument as shown in Figure 10 Figure 10 instrument connection for measuring ground noise voltage Potential stake A Electrode under test DETSTD Potential stake Electrode under test DET4TD 28 Potential stake A Electrode under test DET3TC Potential stake DET4TC ae te DET4TCR Set the rotary selector switch to the V position The ground noise voltage reading will be displayed as shown in Figure 11 Figure 11 example ground noise voltage reading DET4TC DET4TCR display shown 29 Note B The instrument will display the warning triangle and an excessive noise voltage indicator above 40 V pk pk 14 Vrms B The instrument will display the warning triangle and an over range condition above 100 V Measurement of ground noise voltage DET3TA 1 Ensure the rotary selector switch is in the OFF position 2 Connect the instrument as shown in Figure 12 Figure 12 instrument connection for measuring ground noise voltage Potential stake V4 Wg Electrode under test 9 Set the rotary selector switch to the V position 4 The ground noise voltage reading will be indicated on the scaleplate as shown in Figure 13 Figure 13 example ground noise voltage reading 30 Two terminal resistance measurement DET3
33. nect the instrument as shown in Figure 28 Figure 28 instrument connection for measuring four terminal resistance o DET4TD DET4TC DET4TCR 2s Set the rotary selector switch to the position 4 Select the desired test voltage using the PRAVEIUBM button 5 Press and release the TEST button by holding the TEST button the resistance measurement will be continually updated 44 6 E The instrument will perform pre measurement check the status of which will be indicated on the display The four terminal resistance reading will be displayed as shown in Figure 29 Figure 29 example four terminal resistance reading DET4TC DET4TCR display shown 8 A soil resistivity value can be derived from the resistance reading and the stake geometry Note B The instrument will display the warning triangle and an excessive noise voltage indicator if the ground noise voltage is above 40 V pk pk 14 Vrms B The instrument will display the warning triangle and a voltage over range condition if the ground noise voltage is above 100 V no resistance reading is possible under this condition 45 Measurement of ground current DET3TC DET4TC and DET4TCR Before measuring ground current please follow the procedure contained in the section on ICLAMP calibration 1 Ensure the rotary selector switch is in the OFF position Z Connect the instrument as shown in Figure 30 Figure 30 instrument connection for measurin
34. on and that they contact completely when the ICLAMP is closed Currents carried by conductors in close proximity to the ICLAMP may affect calibration and reduce the accuracy of measurements made 50 Three terminal resistance measurement with lead null using ART DET4TC and DET4TCR In certain circumstances the resistance of the test leads connecting to the electrode under test may itself form a significant part of the measurement electrode resistance This effect can be eliminated using the lead null technique described in this section Before making a measurement using ART please follow the procedure contained in the section on ICLAMP calibration 1 Ensure the rotary selector switch is in the OFF position 2 Connect the instrument as shown in Figure 34 Figure 34 instrument connection for measuring three terminal resistance with lead null using ART Electrode V4 DET4TC Potential stake DET4TCR o Close the ICLAMP around the conductor under test 4 Set the rotary selector switch to the L E position 5 Press and release the TEST button by holding the TEST button the resistance measurement will be continually updated 6 The instrument will perform pre measurement checks the status of which will be indicated on the display s The three terminal resistance reading with lead null using ART will be displayed as shown in Figure 35 51 8 Figure 35 example three terminal resistance reading with lead nul
35. play symbols DET3TC DET3TD DET4TD DET4TC and DET4TCR Symbol Meaning A N Warning triangle Refer to user guide IL Fuse blown TOU Battery indicator ARTY Situation is suitable for making ART measurements DET3TC DET4TC and DET4TCR only 10 vv v vx Cre CL m es LIC x Situation is not suitable for making ART measurements DET3TC DET4TC and DET4TCR only Indicates that the ground noise voltage exceeds the instrument measurement capability test is inhibited Potential stake P stake is within range for accurate measurement Potential stake P stake resistance exceeds range for accurate measurement Current stake C stake is within range for accurate Measurement Current stake C Stake resistance exceeds range for accurate measurement Ground noise voltage is within range for accurate measurement of resistance Ground noise voltage exceeds range for accurate measurement of resistance ICLAMP is connected VCLAMP is connected DET3TC DET4TC and DET4TCR only ICLAMP is not connected VCLAMP is not connected DET3TC DET4TC and DETATCR only Sufficient ICLAMP current DET3TC DET4TC and DET4TCR only Insufficient ICLAMP current DET3TC DET4TC and DET4TCR only Display symbols DET3TA Symbol O Rc Rc LH SLM Meaning Current stake C Stake resistance exceeds range for accurate measurement OR Fuse blown Current stake C stake is within range for accura
36. s are re inserted 1 Switch the instrument on in to the E34 position while holding down the TEST button The display will carry out a self test then briefly display the software version number 2 The screen will show the letters tst release the TEST button 3 The Charger Enable Screen will be shown see below ee b r La 4 The state of the charger circuit is shown by either a cross or a tick being shown below the letters CHg A cross indicates that the charger circuit is disabled X 5 Ifthe cross is shown re enable the charger by pressing the TEST button once the cross should change to a tick 6 Switch the instrument OFF to save the new setting 21 FUSE Fuse status indication DET3TC DET3TD DET4TD DET4TC and DET4TCR The fuse blown status indicator is displayed whilst the instrument is switched on and performing a test as shown Fuse blown Fuse status indication DET3TA The fuse blown indication is given by the Rc LED when performing a test as shown Fuse blown Hc Fuse type All instruments 500 mA F HBC 50 kA 600 V 32mm x 6mm Megger part number 25950 056 Fuse replacement Warning Do not operate instrument with the battery cover removed Warning Fitting an incorrect fuse type will reduce operator safety 1 To avoid the possibility of electric shock switch instrument OFF and disconnect the instrument from any electrical circuits 2 The rear
37. s to 25 V for operation in situations which require it The most appropriate output voltage should be selected by the operator based on local safety procedures The procedure for changing the output voltage is as follows DET3TA 1 Press and hold the TEST button and switch instrument ON to the V setting using the selector switch 2 The needle will sweep across the scaleplate and return to the rest position On older DET3TC and DET3TD instruments the firmware version will be displayed followed by tst 9 Release TEST button The maximum output test voltage will be displayed either 50 V or 25 V 4 To toggle between the maximum output test voltages press the TEST button 25 Switch off instrument when the desired maximum test voltage is displayed DET3TC DET3TD DET4TD DET4TC and DET4TCR 1 Press the MEYMEID button after selecting the measurement mode the display will indicate the selected output voltage Note For ART mode the output voltage is automatically set to 25 V and cannot be changed Note Some older versions of the DET3TC and DET3TD do not have the the PRYMEIOM button The procedure for changing the output voltage is as per the DET3TA Auto power down To extend battery life the instrument will automatically switch off six minutes after the last operation The instrument can be switched back on by turning the selector switch to the OFF position and then selecting the desired mode of operation Dis
38. stance of approximately 62 between the electrode under test and the current stake i e at A 0 62 x B Figure 5 schematic for three terminal resistance measurement with lead null OD C1 E X P1 ES A Earth electrode under test B Potential stake Current stake In this diagram thefhand terminals are connected together at the electrode under test This is the three terminal with lead null configuration which is only applicable in four terminal testers This configuration allows the resistance of the Il lead to the electrode under test to be nulled out For three terminal testers or when lead null is not required only the terminal or X terminal on a three terminal instrument connects to the electrode under test This is shown in Figure 6 24 Figure 6 schematic for three terminal resistance measurement without lead null m A E P1 ES A Earth electrode under test Potential stake Current stake Principle of operation three terminal resistance measurement using ART The classic three terminal test method has a disadvantage namely that the electrode under test must be disconnected from the system it is supposed to protect in the event of a power system fault The reason for this is that the injected test current will take all possible routes to ground and not all of it will necessarily flow through the electrode under test In this case the instrument will make
39. strument may auto power down at any time 0 battery charge remaining instrument will auto power down Battery status indication DET4TCR The battery condition indicator is displayed whilst the instrument is switched on as shown a LL gt d LL L 3 L 3 L 3 a N i Battery charge remaining Partially charged batteries Some change remaining but instrument may auto power down at any time 18 AE 0 battery charge remaining instrument will auto power m EEB down Note If the DET4TCR s rechargeable batteries are replaced with alkaline batteries the instrument may automatically disable its charging circuit to prevent inadvertent charging of non rechargeable cells Follow the instructions Re enabling the DET4TCR charger circuit to switch the charger back on when the NiMH cells are re inserted Battery status indication DET3TA 1 Set the rotary selector switch to the L Hh position 2 Press and hold the TEST button 2s The battery charge level will be indicated on the scaleplate as shown in Figure 2 Figure 2 battery charge level indicator 00 e 1000 10k 40 60 20 4 Release the TEST button Battery charging DETATCR When the battery status indicator shows a nearly empty or exhausted battery the instrument may be recharged using the following procedure Warning Do not attempt
40. te measurement Instrument is performing pre measurement checks 11 INSTRUMENT ILLUSTRATIONS DET3TA Multi function Test lead analogue display connections at rear Rc OK Jy Megger DETITA Resistance measurement settings 2P and 3P Spike button Selector switch Battery check setting voltage setting Resistance scale Voltage scale Potential test spike resistance indicator s e C la Battery charge K s indicator Test lead connections at rear of instrument 12 DET3TC Test lead LCD display connections at rear Hesistance measurement settings 2P and 3P and clamp Selector switch Voltage and current measurement Test button settings Warning refer to Battery charge Over under range Ruptured fuse user manual indicator indicator indicator LL Measuring range I mA Clamp current oka indicator OK or low gt Lo Roar 4 Potential probe Current probe Ground noise voltage resistance indicator resistance OK or indicator OK high OK or high high Test lead connections at rear of instrument 13 DET3TD LCD display Test lead connections at rear Hesistance measurement settings 2P and 3P Selector switch Test button Voltage measurement settings Over under range Ruptured fuse Warning refer to Battery charge indicator indicator user manual fhdicator Measuring range kO Ko mA Potential
41. trument with the battery cover removed Warning Incorrect battery cell polarity can cause electrolyte leakage resulting in damage to the instrument If the battery condition indicator does not show a full charge when battery cells are new a cell may be reversed Warning To avoid damage by leaking electrolyte or deep discharge do not leave cells fitted in an instrument which will remain unused for extended periods of time 1 To avoid the possibility of electric shock switch instrument OFF and disconnect the instrument from any electrical circuits 2 The rear cover must not be opened if the test leads are connected 20 9 To avoid the possibility of electric shock do not press the TEST button or touch the fuse when changing batteries 4 To remove the rear cover release the screw at the bottom of the cover and lift the cover upwards 5 Remove the exhausted cells and dispose of in an appropriate manner 6 Refit new batteries of the correct type observing the correct polarity as marked on the battery compartment re Replace the instrument back cover and secure by tightening the retaining screw Re enabling the battery charging circuit on the DETATCR If the DET4TCR s rechargeable batteries are replaced with alkaline batteries the instrument may automatically disable its charging circuit to prevent inadvertent charging of non rechargeable cells Follow the instructions below to switch the charger back on when the NiMH cell
42. wn PA 19403 England U S A Tel 44 0 1304 502 243 Tel 1610 676 8579 Fax 44 0 1304 207 342 Fax 1 610 676 8625 Megger operate fully traceable calibration and repair facilities ensuring your instrument continues to provide the high standard of performance and workmanship you expect These facilities are complemented by a worldwide network of approved repair and calibration companies which offer excellent in service care for your Megger products Returning your product to Megger UK and USA service centres b When an instrument requires recalibration or in the event of a repair being necessary a Returns Authorisation RA number must first be obtained from one of the addresses shown above You will be asked to provide the following information to enable the Service Department to prepare in advance for receipt of your instrument and to provide the best possible service to you B Model e g DET4TC B Serial number to be found on the underside of the case or on the calibration certificate B Reason forreturn e g calibration required or repair B Details of the fault if the instrument is to be repaired 2 Make a note of the RA number A returns label can be emailed or faxed to you if you wish 3 Pack the instrument carefully to prevent damage in transit amp Ensure the returns label is attached or that the RA number is clearly marked on the outside of the package and on any correspondence before sending the
43. y testing according to some local regulations B No resistance reading is possible if the ground noise voltage exceeds 100 V 35 Three terminal resistance measurement DET3TC DET3TD DET4TD DETATC and DETATCR 1 Ensure the rotary selector switch is in the OFF position A Connect the instrument as shown in Figure 19 Figure 19 instrument connection for measuring three terminal resistance Electrode Current stake under test a Potential stake DET3TD Electrode under test Current stake P4 Potential stake DET4TD 36 Electrode under test Current stake rZ Potential stake DET3TC Electrode under test Current stake 5 l DET4TC Potential stake DET4TCR Set the rotary selector switch to the position Select the desired test voltage using the MEMMBIQ button Press and release the TEST button by holding the TEST button the resistance measurement will be continually updated The instrument will perform pre measurement check the status of which will be indicated on the display The three terminal resistance reading will be displayed as shown in Figure 20 37 Figure 20 example three terminal resistance reading DET4TC DET4TCR display shown uot Rp Rc VW 90V Note B The instrument will display the warning triangle and an excessive noise voltage indicator if the ground noise voltage is above 40 V pk pk 14 Vrms B The instrument will display the warning tr
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