20.99 Oct 31, 2025
CD Oct 2, 2026
IEC
TC 112
International Standard
PROJECT
IEC 61857-51 ED1
20.99
WD approved for registration as CD
Oct 31, 2025
Electrical insulation systems - Procedures for thermal evaluation - Part 51: Specific requirements for electrical insulation systems in dry-type resin-encapsulated high-voltage windings using AC dielectric breakdown as diagnostic
10.99 New project approved