Introduction

A coding system is in existence that can be used to assign designations to lamp caps and lampholders. Meaningful assignment can be made to the letters, numbers and symbols that make up this designation. The system has gained international acceptance and should be used as much as possible.

It is self-evident that there is a relationship between a certain lamp cap and the lampholder to be used with it. This relation is reflected in the relevant designation, part of which is used in common for the two products.

As a consequence of this system it is possible to compare caps and holders from various manufacturers and, where they are interchangeable, the same designation can be assigned to them. This system is also a powerful instrument for controlling proliferation of designs. Assignment of designations to new types of cap and holder is the prerogative of the experts group EPC of IEC subcommittee 34B.

New caps should not be given the designation of a cap covered by an existing or withdrawn IEC 60061-1 data sheet. For a list of withdrawn IEC 60061-1 data sheets see IEC 60061-4, sheet 7007-25.