Basic Electrical Installation Work

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use large-diameter pipes, reduce the flow rates liquids and powders and, therefore, reduce the build-up static charge. Petrol pumps, operating theatre oxygen masks and car spray booths are particularly risk because spark these situations may ignite the flam- mable liquid, powder gas. Rubber, which contains proportion graphite, used manufacture antistatic trolley wheels and surgeons’ boots. So how protect ourselves against the risks associated with static electrical charges? said earlier that build-up static charge not apparent between two conducting surfaces, and this gives clue the solution. A nylon overall and nylon bed sheets build static charge which the cause the ‘crackle’ when you shake them. Computer supplies Every modern office now contains computers, and many systems are linked together networked. Static electricity Static electricity voltage charge which builds many thousands of volts between two surfaces when they rub together. dangerous situation occurs when the static charge has built potential capable striking an arc through the airgap separating the two surfaces.Electrical installations and wiring systems 329 appropriate, between and years but not exceeding years (Regulation 721. Rubber constructed this manner enables any build-up static charge ‘leak’ away. A motor car moving through the air builds static charge which some- times gives the occupants minor shock they step out and touch the door handle. Definition Static electricity voltage charge which builds many thousands of volts between two surfaces when they rub together. Static charges build thunderstorm. Increasing humidity also reduces static charge because the water droplets carry away the static charge, thus removing the hazard. Most computer systems are sensitive variations .514. We looked Lighting Protection Systems Chapter 13.1). Hospitals use cotton sheets and uniforms, and use bonding extensively operating theatres. Lightning dis- charge currents are the order 20kA, hence the need for lightning con- ductors vulnerable buildings order discharge the energy safely. Static charge builds between any two insulating surfaces between an insulating surface and conducting surface, but not apparent between two conducting surfaces. Bonding surfaces together with equipotential bonding conduc- tors prevents build-up static electricity between the surfaces. lightning strike the dis- charge the thunder cloud, which might have built voltage of 100MV, the general mass earth which zero volts. Many flammable liquids have the same properties insulators, and therefore liquids, gases, powders and paints moving through pipes build static charge