Circuit Breaker Reference

Data record tests.insulation-power-factor-dissipation-factor.equipment.breaker-vacuum.acceptance

Verified 2026-10-29 Confidence: High

Insulation Power Factor Dissipation Factor is specified for medium-voltage vacuum circuit breakers in acceptance testing at clause 7.6.3.B.7 of ANSI/NETA ATS-2025. The clause calls for power-factor or dissipation-factor tests on each pole with the breaker open and each phase with the breaker closed.

Value: medium-voltage vacuum circuit breakers

ProvenanceANSI/NETA ATS-2025 supports data record tests.insulation-power-factor-dissipation-factor.equipment.breaker-vacuum.acceptance, which is cited on the entry Insulation Power Factor Dissipation Factor.SOURCEANSI/NETA ATS-2025ANSI/NETA ATS-2025Licensed standard, clause 7.6.3.B.7DATA RECORDtests.insulation-power-factor-dissipation-factor.equipment.breaker-vacuum.acceptancetests.insulation-power-f..Verified 2026-10-29ENTRYInsulation Power Factor Dissipation FactorInsulation Power Factor ..No revisions
Provenance. Where this record comes from and where it is used: the cited source, the record itself and the entry that cites it.
Provenance: the chain from source to entry.
StepItemDetail
SourceANSI/NETA ATS-2025Licensed standard, clause 7.6.3.B.7
Data recordtests.insulation-power-factor-dissipation-factor.equipment.breaker-vacuum.acceptanceVerified 2026-10-29
EntryInsulation Power Factor Dissipation FactorNo revisions
Subject
Insulation Power Factor Dissipation Factor (Test methods)
Kind
Equipment fact
Source
ANSI/NETA ATS-2025, clause 7.6.3.B.7, Acceptance Testing Specifications for Electrical Power Equipment and Systems, NETA. Publisher page for ANSI/NETA ATS-2025Publisher information page
Also stated in
  • FIST 3-16, section 6.3.2.2, page 48 (May 2024).
    Read the reference passage

    6.3.2.2 Power Factor or Watt-Loss Test

    "The power factor test is specifically used to determine the condition of the surface insulation of the breaker, it will not give the condition of the vacuum interrupter. [...] This test is to be used with a baseline and the results trended over time."

    FIST 3-16, section 6.3.2.2, page 48, May 2024. Agency copy of FIST 3-16

    The current standard governs; this passage is a public-domain description of the practice dated May 2024.

  • FIST 3-16, section 6.3.2, page 46 (May 2024).
    Read the reference passage

    6.3.2 Insulation and Vacuum-integrity Test

    "The hi-pot test is a pass/fail test and the power factor test will give a value which will usually allow trending. However, the test result of the power factor test is so low that the value obtained may not be able to show a meaningful trend. The power factor test will not give meaningful results pertaining to vacuum-integrity due to the circuit breakers high insulation values."

    FIST 3-16, section 6.3.2, page 46, May 2024. Agency copy of FIST 3-16

    The current standard governs; this passage is a public-domain description of the practice dated May 2024.

  • FIST 4-7, section 6.1.10.2, page 46 (August 2023).
    Read the reference passage

    6.1.10.2 Insulation Test

    "Power factor tests should be performed on each phase with the breaker in both the open and the closed position. Power factor tests should be performed on each bushing of oil-filled breakers. Use conductive straps and the hot collar procedure if bushings are not equipped with a power factor tap. The power factor of an insulation should remain constant with increasing test voltage if no discharges are present."

    FIST 4-7, section 6.1.10.2, page 46, August 2023. Agency copy of FIST 4-7

    The current standard governs; this passage is a public-domain description of the practice dated August 2023.

History

Every recorded change to this data record, oldest first.
DateChange
2026-10-29created

Cite this page

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

"Data record tests.insulation-power-factor-dissipation-factor.equipment.breaker-vacuum.acceptance." Circuit Breaker Reference. 2026-10-29. https://www.circuitbreakerreference.com/data/tests.insulation-power-factor-dissipation-factor.equipment.breaker-vacuum.acceptance/.