This chapter discusses main methods of wiring a lighting installation. The IET Regulations recommend that every consumer's installation should have a means of isolation, a means of overcurrent protection and a means of earth leakage protection. Industrial installations differ basically from domestic and commercial ones only in the size and type of equipment used. In installations with only a light off-peak load, the time clock contacts are able to control the load directly. Only systems supplying equipment in these zones are permitted. Metal cable sheaths or metallic covering of wiring systems shall be connected to the supplementary equipotential bonding. The user of the installation should be provided with plans and diagrams showing the location of all equipment, concealed cable routes, distribution and the equipotential bonding system. Portable electrical apparatus should only be permitted in any hazardous area in the most exceptional circumstances which make any other alternative extremely impracticable, and only then if it is of a certified type.