This document discusses general electrical systems in buildings. It covers basics like earthing systems, wiring, industrial installations, lighting controls, light sources and lamps. It describes how an electrical system carries and distributes power safely from the point of delivery to various loads. Basic installations include lighting, exhaust fans, portable appliances and their wiring network. It also discusses fire safety systems, energy efficiency standards, and methods of wiring like joint box and loop-in systems. The document outlines types of lighting controls and different lighting designs. It concludes with an overview of telecommunication installation media like twisted pair, coaxial cable, fiber optics and various wireless transmission methods.