Liquid filled transformers
Updated 2026-10-27
Data records
- Chapter 11 of NFPA 70B-2026 covers the maintenance of power and distribution transformers; its periodic maintenance procedures are visual inspection, cleaning, mechanical servicing and electrical testing, with the lubrication and special subdivisions reserved.
- Table 11.3.5 of NFPA 70B-2026 lists the transformer electrical tests, among them core insulation resistance, excitation current, insulation power factor and its tip-up, bushing power factor, turns ratio, winding resistance, bolted connection resistance, sweep frequency response analysis and a set of insulating-fluid tests that includes dissolved gas analysis and furan analysis.
Elsewhere in the family
- Liquid-filled transformers more on this entry on Transformer Testing Reference
Sources
- NFPA 70B-2026, Standard for Electrical Equipment Maintenance, 2026 edition, NFPA. Cited: clause Chapter 11; clause Table 11.3.5. Held as: Purchased single-user copy.
Obtaining the documents
- NFPA 70B-2026: publisher catalog or sales page
Changelog (2 entries)
| Date | Revision | Change |
|---|---|---|
| 2026-10-27 | created (equip.liquid-filled-transformers.nfpa70b.chapter) | |
| 2026-10-27 | created (equip.liquid-filled-transformers.nfpa70b.electrical-tests) |
Cite this page
Cite the governing standard for the fact itself; cite this page as the finding aid.
"Liquid filled transformers." Electrical Maintenance Reference. 2026-10-27. https://www.electricalmaintenancereference.com/equipment/liquid-filled-transformers/.
Electrical Maintenance Reference, Liquid filled transformers (Oct. 27, 2026), https://www.electricalmaintenancereference.com/equipment/liquid-filled-transformers/.
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title = {Liquid filled transformers},
howpublished = {\url{https://www.electricalmaintenancereference.com/equipment/liquid-filled-transformers/}},
organization = {Electrical Maintenance Reference},
publisher = {Electrical Maintenance Reference},
year = {2026},
note = {last substantive change 2026-10-27}
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