Right caps for the right lamps

Precision adjustment to standards

There are dozens of models of lamps for countless applications, for residential, industrial and office lighting, for domestic appliances, medical lighting and projection equipment, within the automotive industry, etc. Lamp caps and holders must be standardized to ensure lamps designed for the same purpose are interchangeable. IEC SC (subcommittee) 34B: Lamp caps and holders, prepares the IEC 60061 series of International Standards to ensure this is the case. Three amendments to the series have just been published.

A long involvement

IEC work on lamp caps and holders and gauges used to measure them precisely dates back to 1925, when an Advisory Committee for the standardization of lamp caps and holders was set up with the objective of achieving international interchangeability. The committee cooperated with INDECO (the Independent Committee on Standardization of Lamp Caps and Holders) up to May 1939.

Activities resumed in 1947 following an interruption caused by the war and IEC TC (Technical Committee) 34: Lamps and related equipment, was created in 1948.

The first edition of "International recommendations regarding lamp caps and holders together with gauges for the control of interchangeability", prepared by SC 34B: Lamp caps and holders, was published in 1952, under the reference "Publication 61". This first publication was later expanded, becoming the IEC 60061 series of International Standards, a database of Standard sheets for all lamp caps, holders and gauges.

Regular updates needed

Lamp caps and holders are identified by a coding system that comprises letters, numbers and symbols, such as E27 for a 27 mm diameter Edison screw cap lamp, or BC22 for a 22 mm diameter bayonet cap lamp. New types of caps and holders are introduced on a regular basis.

In view of the increasing number of Standard sheets contained in IEC 60061, in 1969, when the third edition of this International Standard was published, it was decided to split the single publication into three parts, numbered IEC 60061-1, IEC 60061-2, IEC 60061-3, covering lamp caps, Iampholders and gauges, respectively. A supplementary part, IEC 60061-4: Guidelines and general information, was added in 1990.

As new types of lamps are being introduced, such as LED-based bulbs which may require a heat spreader, for instance, this database is updated on a regular basis. Three Amendments, for parts 1-3:Lamp caps and holders together with gauges for the control of interchangeability and safety, were published in September 2012.

Latest amendments

Amendment 48 to IEC 60061-1: Lamp caps, concerns five types of lamp caps and includes drawings and details of these caps.

Amendment 45 to IEC 60061-2: Lampholders, concerns three types of lampholders whose characteristics match those of three of the caps listed in Amendment 48 to IEC 60061-1.

Amendment 46 to IEC 60061-3: Gauges, gives details for gauges used to check maximum insertion and withdrawal torques in lampholders and for "go" and "no go" gauges for checking pin diameters of caps for the base.

The numbering of these amendments from ̶ 45 to 48 ̶ gives an indication of the frequent changes made to lamp caps and holders and to the gauges used to control interchangeability and safety.

These frequent amendments require a precise procedure to keep the database up to date. Detailed instructions for removing the existing title page, content, foreword, existing contents by designation and the individual Standards sheets themselves, as well as for inserting replacement pages and amended Standards sheets, are clearly given in each amendment, together with the precise numbers of the content being replaced.

The IEC 60061 database is constantly updated as the amended Standard sheets are inserted as soon as they are published, ensuring subscribers always have access to the latest information.

All the amendments together with the entire IEC 60061 database are essential for the lamp, luminaire and related industries to ensure they manufacture the right products.