Overview
IEC 60238:2016 - Edition 9.0 is the International Electrotechnical Commission standard for Edison screw lampholders. It applies to lampholders with Edison threads E14, E27 and E40, and to certain E5 and E10 lampholders used with series-connected lamps. The standard covers lampholders intended for connection to lamps and semi-luminaires, including switched-lampholders for AC circuits with a working voltage up to 250 V r.m.s. This edition (2016) is a technical revision of the previous edition and introduces notable changes such as a pull test for some E5/E10 lampholders and an Annex D identifying clauses that require retesting.
Key topics and requirements
The standard specifies design, safety and test requirements including:
- Scope & classifications - applicability to indoor/outdoor, built-in and luminaire-integral lampholders, adapters and candle lampholders where relevant.
- Electrical safety - protection against electric shock, insulation resistance and electric strength tests, and switching requirements for switched-lampholders.
- Mechanical requirements - mechanical strength, pull and torque tests, impact and tumbling tests, and dimensional requirements for thread and contacts.
- Thermal and fire resistance - general heat resistance, resistance to heat, fire and tracking, and requirements to resist season cracking and corrosion.
- Terminals & earthing - terminal dimensions, connection requirements and provision for earthing where applicable.
- Creepage & clearance - minimum distances for impulse and operating voltages.
- Marking & documentation - labelling, standard ratings and product identification.
- Test methods & figures - extensive test apparatus, test caps and tables are included (mechanical, electrical and thermal test procedures, and normative/ informative annexes).
- Annexes - guidance for switches (Annex B referencing IEC 61058-1), special appliance requirements, season cracking test, and an Annex D listing amended clauses requiring retest.
Practical applications - who uses this standard
IEC 60238 is used by:
- Lampholder and lighting manufacturers for product design, compliance and type testing.
- Luminaire and appliance OEMs when integrating lampholders - lampholder clauses are applied alongside relevant appliance standards.
- Test laboratories and certification bodies for conformity assessment and safety testing.
- Specifiers and procurement teams looking to verify safety, interchangeability and mechanical robustness.
- Retailers and OEMs for guidance on which lampholders are intended for retail sale (some E10/E5 types and snap-on shells are restricted for manufacturer use).
Related standards
- IEC 61058-1 (switches) - guidance for switches used in lampholders (see Annex B).
- IEC 60529 - referenced for standard test finger (accessibility) used in mechanical tests.
Keywords: IEC 60238, Edison screw lampholders, E14 E27 E40, lampholder standards, switched lampholders, product testing, safety requirements, lighting components.
