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1. SSner OPERATING MANUAL DEMONSTRATION BOARD DB 1 Revision 1 1 Juli 15 2009 pps 4 4 1 4 1 2 4 2 4 2 1 4 3 1 4 3 1 1 4 3 1 2 4 3 1 3 4 3 1 4 4 3 1 5 4 3 2 4 3 2 1 2 3 2 2 4 3 2 3 4 4 4 5 4 5 1 4 5 2 4 6 1 4 6 2 T O ae TABLE OF CONTENTS EnttOduc TODO eed N DM M M EE 3 SOC dtu gs one ed CM sopa LAM alent E t ao E op ase UN dps 4 The front panel arrangement of sockets and switches 5 Measurements ara r a ri i i a 7 Measurement of the short circuit loop impedance T Measurement of the short circuit loop impedance in the L PE circuit J Measurement of the short circuit loop impedance in the 9 Measurement ofthe parameters of the RC D esci iii uot 9 Realisation of measurements of the RCD switch parameters 10 Measurements of the earth TeSISLance aet edere eai us ub cedens dee deua desea 11 Measurement of the earth electrode resistance using meters of MRU series 12 Earth resistance measurement eee Eire ied 12 Earthi resistance meastirement Rer oso eite ever oe eR Freund iet obse 12 Earth resistance measurement Rg by means of the technical method 13 Earth resistance measurement Rg2. The DB 1 demonstration board is an indispensable element of training courses regarding realisation of electric measurements It may be applied in schools distribution centres of meters used in the power industry as well as in training centres The board may be used for the purpose of simulation of the following measurements measurement of the short circuit loop impedance in the L N circuit for the TT and TN networks measurement of the short circuit loop impedance in the L PE circuit for the TT and TN networks measurement of the parameters of the RCD switch type AC insulation resistance measurement in the L N circuit insulation resistance measurement in the L PE circuit measurement of the earth resistance by means of the technical method earth resistance measurement using clamps earth resistance measurement by means of the two clamp method earth resistance measurements by means of the impulse method earth resistance measurements using meters for short circuit loop measurements resistivity measurements of three kinds of ground measurement of the resistance of equipotential bondings measurement of alternating voltage The demonstration board makes it possible to cause irregularities in the installation under scrutiny This is possible thanks to the panel switches Note WARNING Before you proceed to operate the device read thoroughly the present manual and observe the safety regulations and instructions spe
3. earth electrode turn the RCD switch on connect meter of the short circuit loop impedance in accordance with Figure 14 perform the measurement the measurement may provoke activation of the RCD switch it is impossible to perform a measurement Figure 14 Connection of the meter Expected results Rge 6 8 ZL N of the network 4 4 Earth resistivity measurements Earth resistivity measurements are used to prepare designs of earth systems in cathode protection or in geology Earth resistivity measurements are performed using four electrodes which are placed in line in equal distances Wenner s method In order to determine the ground resistivity value it is necessary to measure the resistance and perform calculations taking into account the distances between the electrodes Modern meters permit to take into account the distances between the electrodes and all the calculations are performed automatically The meter will display both the resistance value of the measurement probes in Q and the ground resistivity value in In order to perform the measurement proceed as follows disconnect the 230 VAC power supply network cable from the socket of the demonstration board connect earth resistance and ground resistivity meter MRU XXX to the sockets in accordance with Figure 5 place the ground type selection switch at the selected position perform the measurement having previously entered to the met
4. banana plug 0 7m 1 piece c Configuration jumpers 4 pieces d Operating manual e Guarantee card 10 Manufacturer The manufacturer of the board providing the guarantee and post guarantee service is SONEL S A ul Wokulskiego 11 58 100 Swidnica Poland Fax 0 74 858 38 08 E mail export sonel pl Web site www sonel pl Note Solely the manufacturer is authorised to repair the device 23
5. by means of the technical method using current clamps 14 Earth resistance measurement Rg by means of the two clamp method 14 Measurement of the earth resistance using meters for measuring loop impedance 15 resistance nicasurement Ri 5 cocos qq ae d put dd 15 Earth resistance measurement REI sees et ioc ine pei tuse passe pb EE ue 16 Eart resistance qmeasutemelt dee Pere esten reus E evt Ca Ur eased oU Iu 17 vits uctor TRUM 17 Measurements of the continuity of equipotential bondings 18 Measurement of the resistance of the equipotential bonding between and P2 18 Measurement of the resistance of equipotential bonding between and P3 19 IristlattomdTesistance He as ute Die finos pecie rn eot euis E ond meer aec 20 Insulation resistance measurements in the N 8 20 Insulation resistance measurements in the L PE circuits 21 Replacement OF fuse CLOW ILS essed ra e tu Pcia d Daa e etu ul d od d opta dob o eu d dei UN dod 21 LH oou PRO aa E A E A EES EA ET EEE 22 Disinantline and disposal saos aded odd T E A T ae eae 22 Technical dati too N 23 foe oy KM 23 iaaea E an EES ESES 23 1 Introduction
6. error consisting in shunting of the N PE lead with the RCD switch During a measurement with this error the RCD switch will not function and the meter will display an adequate message e g RCD The RCD switch I in the red position causes an additional current leakage in the PE lead During a measurement with this error the RCD switch will be activated at an incorrect moment the and I measurements will not be possible The meter will display an adequate message e g Err Switch Ug in the red position simulates a hazardous touch voltage during a measurement of the RCD parameters Meter will display an adequate message e g Ug gt 25 V If the meter is supposed to block the measurements and display this message the acceptable touch voltage U set for the meter must not exceed 25 V Should the acceptable touch voltage 1 during measurement be set at 50V the meter will perform the measurements and display the results Figure 6 Connection of the meter 10 Expected results Switches green RCD T RCD I and Us for the TN and TT network I 15 30 mA lt 300 ms Up 0 2 V Re 0 00 The RCD switch T red for the TN and TT network message RCD The RCD switch I red for the TN and TT network I lt 15 mA the message Err RCD activated during the measurement Switch Ug red for the TN and TT network I 15 30 mA lt 300 ms Up 31 V Re 1 or excess
7. H20 jumper the earth electrode Rei ZW Ry jumper place a jumper on the Rz earth electrode turn the RCD switch on connect meter of the short circuit loop impedance in accordance with Figure 12 perform the measurement the measurement may provoke activation of the RCD switch it is impossible to perform a measurement 15 c KI o 9 C a aS E Figure 12 Connection of the meter Expected results Rg 100 Zi of the network 4 3 2 2 Earth resistance measurement Rp In order to perform the earth resistance measurement proceed as follows connect the 230 VAC power supply network cable to the socket of the demonstration board remove the TN or TT jumper the ZW H20 jumper the earth electrode Rg ZW Ry jumper turn the RCD switch on connect meter of the short circuit loop impedance in accordance with Figure 13 perform the measurement the measurement may provoke activation of the RCD switch it is impossible to perform a measurement Figure 13 Connection of the meter Expected results Re 4 5 ZL N of the network 16 4 3 2 3 Earth resistance measurement In order to perform the earth resistance measurement proceed as follows connect the 230 VAC power supply network cable to the socket of the demonstration board remove the TN or TT jumper the ZW H20 jumper the earth electrode Rei ZW Ry jumper place a jumper on the
8. a socket without an additional PE connection The board is equipped with a protection constituted by two F 4A 250V fuses T 3 14A 250V fuse are acceptable The fuses are located in the device power supply socket Should the fuse elements be damaged they must be replaced It is unacceptable to use other fuses WARNING Before the fuses are replaced the device must be disconnected from the 230V power supply network 3 The front panel arrangement of sockets and switches Er load curren t 25A 60ms Maximum insulation test voltage 1000 V Do not connect any electrical appliances to this outlet eo I 230V 400V Switch positions error simulation on error simulation off 9 Risou n Figure 1 Arrangements of the panel elements of the DB 1 demonstration board Power supply network socket 230 V Additional PE socket 230 V power supply signalling diode RCD switch Measurement socket TN network jumper TT network jumper Rei ZW earth electrode jumper Equipotential pipe connection jumper H O ZW H O Rz ZW Rr earth electrode jumper Measurement points P1 P2 P3 P4 P5 Measurement point of the E1 earth electrode Measurement point of the Ry E2 earth electrode Measurement electrode sockets Irregularity selection switches Ground type switch for ground resistivity measurements Position of switches simulating irregularitie
9. atch the casing powders pastes etc The electronic system of the demonstration board does not require maintenance 7 Dismantling and disposal Worn out electric and electronic equipment should be gathered selectively 1 it must not be placed with waste of another kind Worn out electronic equipment should be sent to a collection point in accordance with the law of worn out electric and electronic equipment Before the equipment is sent to a collection point do not dismantle any elements Observe the local regulations concerning disposal of packages worn out batteries 22 8 Technical data m Type atinsa OD single in accordance with PN EN 61010 1 b Measurement Cate OF V cu od erred rit Ets preis to II 300 V in accordance with PN EN 61010 1 Protection grade of the casing in accordance with IP40 d Powersupply ofthe Meter 230 V e P ee iR Tm 405 x 300 x 140 mm D WV NAGS Or 1915 uo RTT TRES approximately 3 6 kg gj SOE 0 1119102 1 1 NOM P 20 60 C BV ed SI CIL RN omm 10 40 C i Quality standard development design and production in accordance with ISO 9001 EMISIT fuses 2 x T3 14A 250V or 2xFA4A 250 V Ki POWCECODSUPIDIODoi approximately 15 mW DNE BI RE SUITE 30 mA type AC 9 Accessories a Power supply cord 1 piece b Auxiliary cable banana plug
10. cified by the manufacturer WARNING The demonstration board has been designed for the purpose of simulation measurements of alternating voltage impedance short circuit earth resistance parameters of the RCD switch ground resistivity insulation resistance resistance of equipotential bondings Any application that differs from those specified in the present manual may cause damage of the device and be a source of a serious danger for the user WARNING The DB 1 demonstration board may be used solely by qualified personnel who have appropriate certificates that entitle them to work on electric installations or by persons working under their supervision Using the board by unauthorised personnel or without supervision of such personnel may cause damage of the device and be a source of a serious danger for the user WARNING Before and during measurements of ground resistivity insulation resistance resistance of equipotential bondings earth resistance by means of the technical methods disconnect the power cable of the device from the power supply socket and turn the RCD switch off The power supply of the board is signalled by the POWER ON diode 2 Safety The DB 1 demonstration board has been designed for the purpose of simulation of measurements whose results determine the safety conditions of a virtual installation Therefore in order to guarantee appropriate operation and correctness of the obtained results the following re
11. commendations must be followed Before you proceed to operate the device read thoroughly the present manual and observe the safety regulations and instructions specified by the manufacturer The device has been designed for operation at the nominal voltage of 230V 50Hz The device cannot be used in the grid and with other devices in special interiors for example those of a dangerous atmosphere regarding the risk of explosion or fire It is unacceptable to operate the following 1 adamaged device which is completely or partially out of order 2 a device with damaged power cable insulation 3 a device stored for an excessive period of time in disadvantageous conditions e g excessive humidity If the meter has been transferred from a cool to a warm environment of a high level of relative humidity do not perform the measurements until the meter has been warmed up to the ambient temperature approximately 30 minutes 4 a device with damaged housing Before measurement of connection resistance or insulation resistance make sure the measured object has been disconnected from the power supply Disconnect the power cable of the device from the power supply contact and turn the RCD off Repairs may be performed solely by an authorised service point Before the device is connected to the power supply network make sure the power supply socket is equipped with a properly connected earth pin The board will not function if it is powered from
12. e connect the earth resistance meter MRU XXX to the sockets in accordance with Figure 9 perform the measurement Figure 9 Connection of the meter Expected results 6 8 200 Q 200 0 13 4 3 1 4 Earth resistance measurement by means of the technical method using current clamps In order to perform the earth resistance measurement using clamps proceed as follows disconnect the 230 VAC power supply network cable from the socket of the demonstration board since the measurement of the measurement current is performed with clamps the user is free to place all the jumpers use an auxiliary lead instead of the jumper on the E2 connect the earth resistance meter MRU XXX to the sockets in accordance with Figure 10 perform the measurement Figure 10 Connection of the meter Expected results Rg 6 8 Q 4 3 1 5 Earth resistance measurement Ry by means of two clamp method In order to perform the earth resistance measurement by means of the two clamp method proceed as follows disconnect the 230 VAC power supply network cable from the socket of the demonstration board place a jumper on the ZW remove the TN or TT jumper and the ZW jumper use an auxiliary lead instead of the jumper on the E2 connect the earth resistance meter MRU XXX to the sockets in accordance with Figure 11 perform the measurement 14 Figure 11 Conn
13. ection of the meter Expected results Re 11 5 Q 4 3 2 Measurement of the earth resistance using meters for measuring loop impedance Measurements of the earth resistance may also be performed with meters for measuring the short circuit loop impedance In order to perform such measurements the phase conductor of the power supply network is used as an auxiliary source of voltage which permits to generate the measurement current The result of the measurement is a sum of the impedance of the tested earth resistance the working earth system the source and the phase conductor and thus it is burdened with a positive error However if it does not exceed the acceptable value for the tested earth system it may be assumed the earth system is properly constructed and there is no need to apply more precise measurement methods Certain meters used for the purpose of measurements of the short circuit loop impedance may activate the differential RCD switch This may influence the maximum measurement current and the time of generating such current by the meter In order to avoid activation of the RCD switch it is recommended to use the measurement of the short circuit loop impedance in the Z PE RCD function 4 3 2 1 Earth resistance measurement In order to perform the earth resistance measurement proceed as follows connect the 230 VAC power supply network cable to the socket of the demonstration board remove the TN or TT jumper the ZW
14. er the appropriate value of the distances between the measurement electrodes 17 5m p 310m 10m p 2950m 20m p 5 9kOm Figure 15 Connection of the meter Expected results Switch in the position 5 m p 2 31 Om Switch in the position 10 m p 295 Om Switch in the position 20 m p 5 9 kOm 4 5 Measurements of the continuity of equipotential bondings Using the demonstration board it is possible to simulate a measurement of the resistance the equipotential bonding of an electric installation The measurement may be performed between point P1 of the equipotential bonding and point P2 or P3 It is also possible to simulate irregularities related to the resistance of the equipotential bonding of point P2 and point P1 In order to activate this function the Rg switch simulating the irregularity must be placed in the red position 4 5 1 Measurement of the resistance of the equipotential bonding between P1 and P2 In order to perform a measurement of the resistance of equipotential bonding between P1 and P2 proceed as follows disconnect the 230 VAC power supply network cable from the socket of the demonstration board place all the switches simulating irregularities in the green position turn the RCD switch off connect the meter with cables to the network socket of the board in accordance with Figure 16 perform the measurement change the position of the irregularities switch Rg to the red position perfo
15. he measurement proceed as follows connect the 230 VAC power supply network cable to the socket of the demonstration board select the kind of network TT or TN using the jumper in the appropriate position Figure 3 all the switches simulating irregularities must be in the green position turn the RCD switch on connect the meter to the power network socket of the board using leads in accordance with Figure 4 perform the measurement The demonstration board permits to perform measurements of a short circuit loop whose value may be artificially overstated simulation of irregularities In order to do so before you proceed to perform the measurement place the Zi switch in the red position Having finished the measurement place the switch again in the green position Figure 5 Connection of the meter Expected results Switch 21 green for the TN network TN jumper Zi x ZL N of the network 1 1 Q Switch 21 red for the TN network TN jumper Zin ZL N of the network 5 5 Q Switch Zi green for the TT network TT jumper Zi N ZL N of the network 1 1 Q Switch Z4 red for the TT network TT jumper Zi N ZL N of the network 5 5 Q Z n of the network the network impedance in circuit of the socket to which the demonstration board cable is connected 4 2 Measurement of the parameters of the RCD switch The principal function of the RCD switch Residual Curren
16. ive Ur voltage 4 3 Measurements of the earth resistance The quality of the earth systems significantly influence the safety of operation of electric installations and devices and particularly the reliability of the protection from electric shock and lightning protection Earth systems have also other functions related to safety namely they are used to carry off electric charge where there is a risk of explosion e g at petrol stations In order to revise electric installations and fulfil the requirements related to the protection from electric shock it is necessary to perform the measurements of earth resistance The resistance in question permits to determine the value of touch voltage which may be generated between different conductive elements of the protective lead In the case of measurements of a single earth system the most common method is the 3 pole potential drop method It consists in driving measurement electrodes into the ground near the earth system under test and forcing the passage of current in the following circuit meter the earth system in question current electrode meter Measurements of multiple earth systems may be performed using the aforementioned method disconnecting subsequent earth electrodes during the measurement Since it is an arduous task the meters which are equipped with clamps may perform the measurement without the necessity to disconnect the measured earth system In the case of this method the current a
17. nd voltage electrodes are placed in a similar manner to the 3 pole method but the current is measured with clamps which are fastened to the earth system under test The meter calculates the resistance knowing the current flowing through the tested earth electrode and ignoring the current flowing through the adjacent earth electrodes However the measurement method with clamps cannot be applied in those multiple systems in which individual earth electrodes are interconnected below the ground Measurements of multiple earth systems may be performed by means of the two clamp method This measurement is performed with two pairs of clamps apart from the measurement clamps also transmission clamps must be used whose internal structure is different The transmission clamps induce current in the tested circuit The value of the current is measured with measurement clamps The result of the measurement is the resistance of the whole circuit through which the measurement current is flowing Using this method remember of the requirements this function is excellent for the purpose of measurements of multiple earth systems of low and medium resistance values In order to obtain a correct measurement the resistance of the earth electrode must be significantly higher than the resultant resistance value for the whole earth electrode system the two clamp measurement measures the sum of the resistance of the tested earthing resistance and the resultant value of the
18. o the network socket in the board in accordance with Figure 19 perform the measurement change the position switch of the irregularities of the resistance of insulation R soa rg to the red position perform the measurement Figure 19 Connection of the meter Expected results Switch Risoa pr green position Risoa P5 gt 3 GO Switch Risoa pr red position 200 5 Replacement of fuse elements In the case a defect of the device has been detected when the signalling diode POWER is off in spite of a correct connection of the device to the 230V 50Hz power supply network it is recommended to check the condition of the fuse elements The fuse elements are in the mains socket from which the device is powered In order to do so disconnect the power supply cord from the device and raise the fuse compartment using flat screwdriver The compartment contains two fuse elements 21 230V AC 2xF4A Figure 20 Position of the fuse elements NOTE Solely the following fuse elements are approved for the demonstration board F4A 250V or T3 15 250V In the case fuse elements which are not specified in the present manual are used there is a risk of damage to the device and a serious danger for the user 6 Cleaning and maintenance The casing of the device may be cleaned with a soft damp cloth using all purpose detergents Do not use any solvents or cleaning agents which might scr
19. of the board using leads in accordance with Figure 4 perform the measurement The demonstration board permits to perform measurements of a short circuit loop whose value may be artificially overstated simulation of irregularities In order to do so before you proceed to perform the measurement place the switch in the red position Having finished the measurement place the switch again in the green position 1 Jumper simulating measurements in the TN network 2 Jumper placed simulating measurements in the TT network Figure 3 Network type selection jumpers Figure 4 Connection of the meter Expected results Switch Zi green for the TN network TN jumper Zip ZL N of the network 1 4 Q Switch Z4 red for the TN network TN jumper Zire ZL N of the network 5 5 Q Switch 21 green for the TT network TT jumper 2 ZL N of the network 5 5 Q Switch Zi red for the TT network TT jumper Zi p ZL N of the network 10 Z n Of the network the network impedance in circuit of the socket to which the demonstration board cable is connected 4 1 2 Measurement of the short circuit loop impedance in the L N circuit Measurements may be performed with any meter for measurements of the short circuit loop whose short circuit current does not exceed 25 A and whose measurement time does not exceed 60 ms e g MZC 30X MZC 20X MPI 5XX In order to perform t
20. other earth resistances The principal and considerable advantage of this measurement is the fact that there is no necessity to drive auxiliary electrodes into the ground There is also another method of an earth resistance measurements This is the measurement of the surge earth resistance The purpose of this measurement is to diagnose the dynamic parameters of lightning protection earth system The surge measurement is performed at an excitation whose shape corresponds to a lightning pulse The parameters of the pulse are defined by two values the duration of the pulse leading edge t and the duration of the semi peak tz The DB 1 demonstration board permits to perform measurements of the earth resistance of three distinct earth electrodes namely Rg Earth resistance measurement is also possible using the clamp method In order to perform such a measurement instead of a jumper at the E2 it is necessary to use an auxiliary lead which is included in the board delivery package and fasten the clamps on the lead In order to perform the measurements it is also possible to use the meters of the MRU 10X and MRU 20X series It is also allowed to use meters dedicated to measurements of the short circuit loop However using such a meter may activate the RCD switch 11 4 3 1 Measurement of the earth electrode resistance using meters of the MRU series 4 3 1 1 Earth resistance measurement Ry In order to perform the earth resis
21. pped with a voltmeter The demonstration board permits a simulation of an insulation resistance measurement The measurement may be performed in the L N and L PE circuits NOTE The test voltage must not exceed 1kV 4 6 1 Insulation resistance measurements in the circuits In order to perform the measurement of the insulation resistance in the L N circuit proceed as follows disconnect the 230 VAC power supply network cable from the socket of the demonstration board place all the switches simulating irregularities in the green position turn the RCD switch off connect the meter with cables to the network socket in the board in accordance with Figure 18 perform the measurement change the position switch of the irregularities of the resistance of insulation Rrsoa w to the red position perform the measurement Figure 18 Connection of the meter Expected results Switch Risoa N green position 100 MQ Switch Risoa N red position 100 20 4 6 2 Insulation resistance measurements in the L PE circuits In order to perform the measurement of the insulation resistance in the L PE circuit proceed as follows disconnect the 230 VAC power supply network cable from the socket of the demonstration board place all the switches simulating irregularities in the green position turn the RCD switch off connect the meter with cables t
22. rm the measurement 18 1 D o O9 Figure 16 Connection of the meter Expected results Switch Rg in the green position Reon P1 P2 0 4 Q Switch Rg in the red position Reon P1 P2 1 4 5 2 Measurement of the resistance of equipotential bonding between P1 and P3 In order to perform a measurement of the resistance of equipotential bonding between P1 and P3 proceed as follows disconnect the 230 VAC power supply network cable from the socket of the demonstration board place all the switches simulating irregularities in the green position turn the RCD switch off insert the ZWH O jumper connect the meter with cables to the network socket of the board in accordance with Figure 17 perform the measurement Figure 17 Connection of the meter Expected results Ro P1 P3 040 19 4 6 Insulation resistance measurement The purpose of the insulation resistance measurements is to determine the conditions of the installation insulation and electric power loads The conditions of the insulation is a decisive factor in the context of safety of operation and correct functioning of electrical devices Good insulation is apart from other means of protection also a guarantee of protection from direct touch Before the measurements are performed make sure the measured object is disconnected from the power supply network This is why the meters manufactured by SONEL S A are equi
23. s in the electric installation of the measured object 1 2 3 4 5 6 7 ISO L N Figure 2 Positions of switches Rx High earth resistance at P2 Rg 1 Us The acceptable voltage value Ug has been exceeded during measurements of the RCD parameters in the measurement socket Ug 25 V Risoa Pr Low insulation resistance measurement L PE Risoa rr 200 RisoaN Low insulation resistance measurement L N Risow n 100 RCD T4 The acceptable disconnection time of the RCD has been exceeded Zu High short circuit loop impedance 21 5 6 RCD I The activation current of the RCD is lower than the required value damaged RCD or excessive leakage current of the installation The leakage current of the installation I4 15 mA 4 Measurements 4 1 Measurement of the short circuit loop impedance A reliable and the most commonly used method of protection from electric shock consists in protection from indirect touch in circuits equipped with circuit breakers The method consists in a automatic disconnection in the case of fault Conductive elements of the device are connected to the protective conductor of the power supply network At the moment a hazardous touch voltage appears which is caused by a metallic short circuit with the phase conductor of the power supply network the current will flow in the phase protective conductor circuit The current is called shor
24. t Device is to provide additional protection against electric shock The purpose the RCD switch is to disconnect the protected circuit in the case of an excessive leakage current in the circuit in question The measurement section of the RCD switch measures constantly the differential current I4 and causes disconnection of the protected circuit from the power supply source if the differential current exceeds the characteristic value for the given switch The value in question is the nominal differential current which is indicated by the symbol Ian The voltage on the housing of the protected device in accordance with the Ohm s law 1s Us L R where Rz is the resistance between the earth terminal of the protected device and the earth 4 2 1 Realisation of measurements of the RCD switch parameters In order to perform the measurement proceed as follows connect the 230 VAC power supply network cable to the socket of the demonstration board select the kind of network TT or TN using the jumper in the appropriate position Figure 3 all the switches simulating irregularities must be in the green position turn the RCD switch on connect the meter to the power network socket of the board using leads in accordance with Figure 6 perform the measurement The demonstration board permits to simulate irregularities in an installation equipped with a RCD switch The RCD switch T in the in the red position simulates an
25. t circuit current The passage of the short circuit current will cause activation of the circuit breakers and the power supply system will be turned off The condition that must be met to have the protection level specified for the device as sufficient approved is that the elements must not be under a dangerous touch voltage for an excessive period of time Therefore the safety device must respond quickly and within the period of time specified in the relevant norms The condition of appropriate protection may be expressed by the following equation Zs short circuit loop impedance Z5 lt I current activating the circuit breaker within the required period of time I x Uo power supply network nominal voltage in relation to earth 4 1 1 Measurement of the short circuit loop impedance in the L PE circuit Measurement of the short circuit loop impedance in the L PE circuit may be performed using the MPI 5XX meter in the 71 function Should another meter or function be used RCD switch of the demonstration board may be trigged In order to perform the measurement proceed as follows connect the 230 VAC power supply network cable to the socket of the demonstration board select the kind of TT or TN network using a jumper in the appropriate position Figure 3 all the switches simulating irregularities must be in the green position turn the RCD switch on connect the meter to the power network socket
26. tance measurement proceed as follows disconnect the 230 VAC power supply network cable from the socket of the demonstration board remove the TN or TT jumper the ZW H20 jumper the earth electrode ZW Ry jumper a jumper may be fastened on the Ry earth electrode connect the earth resistance meter MRU XXX to the sockets in accordance with Figure 7 perform the measurement Figure 7 Connection of the meter Expected results Rg 1000 Ry 200 Q Rs 200 Q 4 3 1 2 Earth resistance measurement In order to perform the Ry earth resistance measurement proceed as follows disconnect the 230 VAC power supply network cable from the socket of the demonstration board remove the TN or TT jumper the ZW H20 jumper the earth electrode ZW Ry jumper a jumper may be fastened on the earth electrode connect the earth resistance meter MRU XXX to the sockets in accordance with Figure 8 perform the measurement 12 Figure 8 Connection of the meter Expected results Rei 4 7 Q Ru z 200 Q Rs 200 Q 4 3 1 3 Earth resistance measurement Ry by means of the technical method In order to perform the earth resistance measurement proceed as follows disconnect the 230 VAC power supply network cable from the socket of the demonstration board remove the TN or TT jumper the ZW H20 jumper the earth electrode ZW Ry jumper place a jumper on ZW Re earth electrod
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