Test Instrument Reference

RCD tester

Updated 2026-10-27

Data records

  • An automatic sequence runs every test on a device in turn and stores the results while the operator stays at the device to reset it after each trip; the stored results are later downloaded for the test record. Source: Megger product page, web page edition. Verified 2026-10-27. Record instr.rcd-tester.auto-sequence
  • An RCD tester injects a controlled residual current into a circuit protected by a residual current device (a GFCI or RCD) and measures the time the device takes to open at that current. Source: Megger product page, web page edition. Verified 2026-10-27. Record instr.rcd-tester.measurand
  • Tests are started at both the positive and the negative zero crossing of the supply waveform, because the tripping time of a device can differ with the polarity of the half cycle in which the fault current begins. Source: Megger product page, web page edition. Verified 2026-10-27. Record instr.rcd-tester.phase-angle
  • In a ramp test the instrument raises the residual current gradually and records the current at which the device actually trips, giving the real tripping current rather than a pass or fail at a fixed level. Source: Megger product page, web page edition. Verified 2026-10-27. Record instr.rcd-tester.ramp-test
  • When connected to a live outlet the tester displays the supply voltage before a test and monitors the voltages between line, neutral and protective conductors, so a wiring fault at the outlet is seen before a residual current is injected. Source: Metrel product page, web page edition. Verified 2026-10-27. Record instr.rcd-tester.supply-check
  • The instrument class is written RCD tester. Value: RCD tester. Source: Electrical Testing Reference editorial taxonomy, 2026-10 edition. Verified 2026-10-27. Record instr.rcd-tester.title
  • Trip time is measured with the test current set at a fraction of the device's rated residual current, at the rated current and at multiples of it, and the instrument reports the measured time at each level for comparison with the limits that apply to the device type. Source: Sonel product page, web page edition. Verified 2026-10-27. Record instr.rcd-tester.trip-time-multiples
  • Residual current devices are classed by the waveform they respond to (types AC, A, F and B, among others) and by whether they are general or time-delayed (selective); the type is selected on the tester, which generates the matching test waveform, including the pulsating and smooth direct currents that some types detect. Source: Metrel product page, web page edition. Verified 2026-10-27. Record instr.rcd-tester.types
  • RCD testing is offered both as a dedicated hand-held tester and as one function of a line and loop impedance tester or a multifunction installation tester, where it shares the same mains connection as the loop test. Source: Metrel product page, web page edition. Verified 2026-10-27. Record instr.rcd-tester.within-multifunction

Sources

  • Electrical Testing Reference editorial taxonomy, Electrical Testing Reference editorial taxonomy of test methods, 2026-10 edition, Electrical Testing Reference. Held as: Own observation.
  • Megger product page, RCDT300 series residual current device testers, web page edition, Megger. Held as: Public page. Publisher page
  • Metrel product page, MI 3122 SMARTEC Line and Loop Impedance RCD Tester, web page edition, Metrel. Held as: Public page. Publisher page
  • Metrel product page, MI 3155 EurotestXD multifunction electrical installation tester, web page edition, Metrel. Held as: Public page. Publisher page
  • Sonel product page, MPI-540 Multi-function meter of electrical system parameters, web page edition, Sonel. Held as: Public page. Publisher page
Changelog (19 entries)
DateRevisionChange
2026-10-27created (instr.rcd-tester.auto-sequence)
2026-10-27review_status unreviewed -> software_reviewed (instr.rcd-tester.auto-sequence)
2026-10-27created (instr.rcd-tester.measurand)
2026-10-27review_status unreviewed -> software_reviewed (instr.rcd-tester.measurand)
2026-10-27created (instr.rcd-tester.phase-angle)
2026-10-27review_status unreviewed -> software_reviewed (instr.rcd-tester.phase-angle)
2026-10-27created (instr.rcd-tester.ramp-test)
2026-10-27review_status unreviewed -> software_reviewed (instr.rcd-tester.ramp-test)
2026-10-27created (instr.rcd-tester.supply-check)
2026-10-27review_status unreviewed -> software_reviewed (instr.rcd-tester.supply-check)
2026-10-27created (instr.rcd-tester.title)
2026-10-27review_status unreviewed -> software_reviewed (instr.rcd-tester.title)
2026-10-27created (instr.rcd-tester.trip-time-multiples)
2026-10-27revised (instr.rcd-tester.trip-time-multiples)
2026-10-27review_status unreviewed -> software_reviewed (instr.rcd-tester.trip-time-multiples)
2026-10-27created (instr.rcd-tester.types)
2026-10-27review_status unreviewed -> software_reviewed (instr.rcd-tester.types)
2026-10-27created (instr.rcd-tester.within-multifunction)
2026-10-27review_status unreviewed -> software_reviewed (instr.rcd-tester.within-multifunction)

Cite this page

Cite the governing standard for the fact itself; cite this page as the finding aid.

"RCD tester." Test Instrument Reference. 2026-10-27. https://www.testinstrumentreference.com/instruments/rcd-tester/.