Basic Electrical Installation Work

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Strana 350 z 399

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58. Emergency lighting not required private homes because the occupants are familiar with their surroundings, but public buildings people are in unfamiliar surroundings. A permanent record the CCTV pictures can stored and replayed by incorporating video tape recorder into the system the practice in most banks and building societies. Escape lighting usually required local and national statutory authori- ties under legislative powers. Emergency lighting provided for two reasons; illuminate escape routes, called ‘escape’ lighting; and enable process activity con- tinue after normal lights failure, called ‘standby’ lighting. most premises the alternative power supply would from batteries, but generators may also used. Definition Emergency lighting not required in private homes because the occu- pants are familiar with their surround- ings, but public buildings people are unfamiliar surroundings. Security cameras should robustly fixed and cable runs designed that they cannot sabotaged potential intruder. FIGURE 14. some premises delay more than considered .Electrical installations and wiring systems 339 Cameras may fixed movable under remote control, such those used for motorway traffic monitoring. 14. The cash points public buildings may need illuminated all times discourage acts theft occurring during mains lighting failure. Emergency supplies Since emergency occurring building may cause the mains supply to fail, the emergency lighting should supplied from source which is independent from the main supply. Emergency lighting (BS 5266 and 1838) Emergency lighting should planned, installed and maintained the highest standards reliability and integrity, that will operate satisfac- torily when called into action, matter how infrequently this may be. Standby lighting may also required for security rea- sons. Pictures from several cameras can multiplexed single co-axial video cable, together with all the signals required for the remote control of the camera. Generators can have large capacity and duration, but major disadvan- tage the delay time while the generator runs speed and takes over the load. Standby lighting required hospital operating theatres and indus- try, where operation process once started must continue, even the mains lighting fails. Typically external camera would be enclosed weatherproof housing such those shown Fig.58 CCTV camera. The escape lighting scheme should be planned that identifiable features and obstructions are visible the lower levels illumination which may prevail during emergency. Exit routes should clearly indicated signs and illuminated uniform level, avoiding bright and dark areas. Definition Emergency lighting provided for two reasons; illuminate escape routes, called ‘escape’ lighting; and to enable process activity con- tinue after normal lights failure, called ‘standby’ lighting. an emergency people not always act rationally, but well illuminated and easily identified exit routes can help to reduce panic. Using remote control, the camera can panned, tilted focused and have its viewing screen washed and wiped. emergency people not always act rationally, but well illuminated and easily identified exit routes can help reduce panic