This is a text for trainees studying Part 1 of the CGLI scheme 236 and other courses leading to an NVQ in Electrical Installation Competences. Meeting the combined requirements of the installation practice of technology competences of the 236 syllabus, the text provides a guide to all subjects included in the Part 1 course. This edition has been revised and updated to incorporate the 16th Edition of the IEE Wiring Regulations, and, when used in conjunction with the IEE's "On-site Guide", provides all the information needed to complete the first year of the 236 scheme.