In this fifth edition of Electrical Principles for the Electrical Trades are many of the ideas and suggestions offered from an Australia-wide representation of teachers and instructors who have been associated with previous editions of this book. Probably the biggest single change has been to the symbols used. This was done in an attempt to update the diagrams to the latest drawing standards given in SAA/SNZ HB3:1996.

This and other standards often give both a form 1 and a form 2 version of the same item, so that I had to make a decision of choice in selecting which symbol to use. Wherever possible I have used the version 1 symbol from the above volume. Different states and colleges quite rightly have their own preferences for the different versions and this puts me in the invidious position of knowing that I cannot please everyone.

There have been modifications to the general text to meet other suggestions, but some of the suggestions, while meriting an earnest consideration, became somewhat impracticable within the confines of one volume. Some sections of the text have been deleted and other sections added. Diagrams have been added, amended or deleted as required to match the text.

There were many requests for the book to be modified to cope exactly with the module system. It was considered unacceptable to adopt this approach, since even a minor change in a module immediately made the book almost useless, unless the relevant parts of the book itself are rewritten.

The book as originally written was intended to be used as both a guide and a reference book for students while studying and hopefully used as a book for referral purposes on later occasions. A student's initial studies are usually undertaken with the assistance of an instructor. As a consequence, the book does not have a multiplicity of photographs and diagrams with a corresponding decrease in the amount of text. There are, however, more than enough diagrams to make the text meaningful, while the instructor as part of the teaching process would supply any required additional material.

Each chapter has a summary of the salient points contained in that chapter and this is followed by both exercises and self-testing problems. There are a total of 621 such items for the student to exercise his or her mind as an adjunct to the learning process. These are unchanged from the previous edition, although the self-testing exercises in Chapter 11 have been rearranged to ensure the degree of difficulty increases as progress is made.