The Electrical Contractors’ Manual was originally a single volume. However, the information contained expanded to such an extent that Council directed that the manual be split into three separate volumes. The cost of completely reprinting and renumbering the Manual and distributing the contents to existing Manual holders could not be justified at this stage. The original contents have therefore been reallocated to Volumes I, II and III and the original numbering retained for the time being. The Electrical Contractors’ Manual has been compiled under main subject headings, and each of these Sections is separated by a tabbed divider. Each main subject heading has been given a number, which forms the first element of a three-part reference number. The main subject headings have been subdivided under topics to facilitate the grouping of items of information as far as is possible and practical. A number has been allocated to each topic, and forms the second element of the reference number. Allowance has been made for the inclusion of related additional (but as yet unknown) topics. Each item of information has also been given a number, which forms the third element of the reference number.