BS IEC 61857-31. Electrical insulation systems. Procedures for thermal evaluation. Part 31. Applications with a designed life less than 5000 hours Electrical insulating materials, Thermal testing, Windings, Electric coils, Compatibility, Electrical components, Assembling, Electrical testing, Diagnostic testing, Dielectric-strength tests, Electrical equipment, Endurance testing, Heat ageing tests, Environmental testing, Stress, Damp-heat tests, Life (durability), Testing conditions, Test equipment