Electrical Testing Reference

Data record tests.insulation-resistance.ieeec57-12-90.significance

Verified 2026-10-24 Confidence: Medium

The notes to clause 10.11 of IEEE C57.12.90-2021 caution that an insulation-resistance reading is a weak indicator next to a dielectric-strength test, because design, temperature, moisture and surface cleanliness all move it, and give it two uses: a periodic trend plotted from readings taken at the same test voltage, and a check of whether a dielectric test can safely be applied; a reading is never taken with the tank under vacuum. The clause supplies neither a minimum megohm figure, nor a polarization index, nor a table of temperature corrections.

ProvenanceIEEE C57.12.90-2021 supports data record tests.insulation-resistance.ieeec57-12-90.significance, which is cited on the entry Insulation Resistance.SOURCEIEEE C57.12.90-2021IEEE C57.12.90-2021Licensed standard, clause 10.11, Notes 1 to 4DATA RECORDtests.insulation-resistance.ieeec57-12-90.significancetests.insulation-resista..Verified 2026-10-24ENTRYInsulation ResistanceInsulation Resistance1 revision
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StepItemDetail
SourceIEEE C57.12.90-2021Licensed standard, clause 10.11, Notes 1 to 4
Data recordtests.insulation-resistance.ieeec57-12-90.significanceVerified 2026-10-24
EntryInsulation Resistance1 revision
Subject
Insulation Resistance (Test methods)
Kind
Method fact
Source
IEEE C57.12.90-2021, clause 10.11, Notes 1 to 4, Test Code for Liquid-Immersed Distribution, Power and Regulating Transformers, IEEE.

History

Every recorded change to this data record, oldest first.
DateChange
2026-10-24created
2026-10-24revised
2026-10-24revised
2026-10-24review_status unreviewed -> software_reviewed

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"Data record tests.insulation-resistance.ieeec57-12-90.significance." Electrical Testing Reference. 2026-10-24. https://www.electricaltestingreference.com/data/tests.insulation-resistance.ieeec57-12-90.significance/.