Loop impedance
Updated 2026-10-27
Data records
- Loop impedance, in full earth fault loop impedance, is the impedance of the path a fault current would follow from the supply source through the line conductor to the point of the fault and back through the protective conductor and the source winding; its value determines the fault current available to operate the protective device.
- An installation tester measures loop impedance between the line and protective conductors and line impedance between line and neutral, offering a high-current mode and a no-trip mode for circuits protected by residual current devices, and it displays the impedance together with the prospective fault current derived from it.
Elsewhere in the family
- Energization Checks related entry on Electrical Testing Reference
Sources
- Electrical Testing Reference editorial taxonomy, Electrical Testing Reference editorial taxonomy of test methods, 2026-10 edition, Electrical Testing Reference. Held as: Own observation.
- Fluke product page, Fluke 1664 FC Installation Multifunction Tester, web page edition, Fluke. Held as: Public page. Publisher page
Changelog (4 entries)
| Date | Revision | Change |
|---|---|---|
| 2026-10-27 | created (gloss.loop-impedance.definition) | |
| 2026-10-27 | review_status unreviewed -> software_reviewed (gloss.loop-impedance.definition) | |
| 2026-10-27 | created (gloss.loop-impedance.usage) | |
| 2026-10-27 | review_status unreviewed -> software_reviewed (gloss.loop-impedance.usage) |
Cite this page
Cite the governing standard for the fact itself; cite this page as the finding aid.
"Loop impedance." Test Instrument Reference. 2026-10-27. https://www.testinstrumentreference.com/glossary/loop-impedance/.
Test Instrument Reference, Loop impedance (Oct. 27, 2026), https://www.testinstrumentreference.com/glossary/loop-impedance/.
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title = {Loop impedance},
howpublished = {\url{https://www.testinstrumentreference.com/glossary/loop-impedance/}},
organization = {Test Instrument Reference},
publisher = {Test Instrument Reference},
year = {2026},
note = {last substantive change 2026-10-27}
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