Drafting

There are several ways to start harmonizing a standard:
- An initial document comes from the International Electrotechnical Commission (80% of cases).
- A document of European origin arises in one of CENELEC's own technical bodies.
- A first draft of a European document comes from one of CENELEC's Cooperating partners.
- A fourth source is the National Committees themselves. Under the Vilamoura Procedure, the NCs have agreed to notify CENELEC when they are planning any new work. CENELEC can, if it wants, take on this work.

Enquiry

When a suitable draft is available, it is submitted to the NCs for CENELEC enquiry, a procedure which lasts 6 months. Then the comments received are studied by the technical body working on the draft and incorporated into the document, where justified, before a final draft is sent out for vote.

Voting

The vote usually takes 3 months. At this stage the members have weighted votes corresponding to the size of the country they represent. For instance, the larger countries like France, Germany, Italy and the UK have 10 votes each while the smaller ones have one or two weighted votes.

There are two requirements for a standard to be approved.
The vote must yield:
- a majority of NCs in favour of the document
- at least 71% of the weighted votes cast are positive

Numbering

The shortest unambiguous reference to a European Standard is to use its number. The number of a European Standard consists of the capital letters EN followed by a space and a number in arabic numerals, without any space.

Example

EN 50225:1996 (the year of availability of the EN is separated from the number by a colon)
EN 50157-2-1:1996 (the part number is indicated by a hyphen)

The first two numerals indicate the origin of the standard:
- 40000 to 44999 cover domains of common CEN/CENELEC activities in the IT field
- 45000 to 49999 cover domains of common CEN/CENELEC activities outside the IT field
- 50000 to 59999 cover CENELEC activities
- 60000 to 69999 refer to the CENELEC implemenation of IEC documents with or without changes.

The IEC and the ISO have allocated themselves blocks of publication numbers: from 1 to 59999 for the ISO and from 60000 to 79999 for the IEC.