METREL A1472 User Manual Download Page 2

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Version note
1.1: manual is valid also for A 1579

© 2014, 2019 METREL

Mark on your equipment certifies that this equipment meets the

requirements of the EU (European Union) concerning safety and

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No part of this publication may be reproduced or utilized in any form or by
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Summary of Contents for A1472

Page 1: ...Leakage current clamp A 1472 A1579 User manual Version 1 2 Code no 20 752 271...

Page 2: ...1 1 manual is valid also for A 1579 2014 2019 METREL Mark on your equipment certifies that this equipment meets the requirements of the EU European Union concerning safety and electromagnetic compatib...

Page 3: ...mps 13 4 2 1 Direct method 13 4 2 2 Differential method 14 4 3 Testing procedures 15 4 3 1 Finding sources of excessive leakage current 15 4 3 2 Insulation resistance testing 17 4 4 Influencing quanti...

Page 4: ...asuring instrument Consider all generally known precautions in order to avoid risk of electric shock while dealing with electric installations and equipment Do not extend hands over protection barrier...

Page 5: ...uitable to work with the A1472 current clamp Main clamp parts 1 Current sensor 2 Protection barriers 3 Conductor opening 4 Signal output terminals 1 2 3 4 A 1472 2 1 Difference to A 1579 The leakage c...

Page 6: ...is possible to use the current clamp on non insulated conductors Symbol on the current clamp indicates possible hazardous live conditions if the required safety measures are ignored Symbol indicates...

Page 7: ...e current clamps and leave them to dry totally before using it Notes Do not use liquids based on petrol or hydrocarbons Do not spill cleaning liquid over the current clamps To clean jaw cut surfaces u...

Page 8: ...rent and insulation resistance between line and earth is defined by the Ohm s law _ k R U mA I ins nom res leak Eq 1 Ileak_res resistive leakage current in mA Unom nominal line voltage e g 230 V Rins...

Page 9: ...very high frequency In general leakage currents in normal operation increase with the size of the electrical installation and the number of connected loads Table 1 shows the values of leakage currents...

Page 10: ...in the installation this can result in an improper current distribution through the neutral and PE conductors Typical faults that usually results in a high fault current that will immediately trip th...

Page 11: ...eakage currents can have different non sinusoidal shapes They are caused by nonlinearity of loads nonlinearity of insulation materials and presence of harmonic voltages and currents in the power syste...

Page 12: ...conductive parts In case of inadequate protective measures this voltage can increase above a safe level and presents a danger for the people if it would be touched Furthermore if the protection devic...

Page 13: ...out R N I U 1 Eq 3 L N L out R N I I U 1 Eq 4 Uout output voltage of current sensor IPE IL IN measured currents RB load burden resistor N number of turns of current clamp The main advantage of the mea...

Page 14: ...conductors earth the sum of currents through active conductors must be exactly zero regardless of the load currents If a leakage current flows it is of the same size as the measured sum between active...

Page 15: ...ferent parallel paths Refer to METRELs handbook Guide for testing and verification of low voltage installations for more information about parallel paths 2 All suspicious loads should be connected If...

Page 16: ...g any of the procedures described above the faulty point can be determined very precisely Fig 7 Finding source of excessive leakage current by disconnection Fig 8 Finding source of excessive leakage c...

Page 17: ...he capacitance The applicability of leakage current measurement as an alternative to the insulation resistance test depends on following factors The ratio between capacitive and resistive leakage curr...

Page 18: ...rrent sensor quality Protective measures are proper magnetic shielding symmetry of the winding twisting of all connection cables high permeability of the sensor core etc 4 4 2 Influence of load curren...

Page 19: ...rby current carrying conductors switchboards etc If the results strongly fluctuate in regard to the current clamp position it is unlikely to get an usable result The reading is not zero although no cu...

Page 20: ...p The immunity of the current clamp against influencing quantities is much more representative The IEC International Electrotechnical Commission is preparing a new international standard IEC 61557 13...

Page 21: ...be beneficial in most of applications 4 5 3 Protection category Overvoltage protection Take care above the overvoltage category of the clamp For use in offices residential industrial domestic sites a...

Page 22: ...ty banana sockets 4 mm Guard terminal Electrical characteristics Measuring range 0 5 mA 10 A Accuracy 5 Frequency range 40 Hz 5 kHz Max input current 100 A Safety specification Type A application arou...