符合规定
发表于 2025-3-23 13:07:36
Sheathed Wiring Systems,PVC-sheathed cables form the overwhelming bulk of cables used for house wiring and are finding increasing application in shops and commercial premises. The make-up consists of conductors (usually copper) with PVC core insulation and a PVC oversheath (figure 3.1).
deviate
发表于 2025-3-23 14:35:40
Conduit Systems,Steel conduits form a major wiring method that requires great installation skill. The system consists of a series of threaded tubes with boxes for the various outlets; cables are drawn through the conduits . erection. Outstanding features are their sturdiness and rewireability so that obsolete cables can be replaced at any time.
无聊点好
发表于 2025-3-23 19:37:22
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dearth
发表于 2025-3-24 00:57:34
Lighting,Lighting was one of the first applications of electricity and still remains of very great importance. Despite the many efficient electric light sources available, the ordinary tungsten filament lamp has an extremely wide application. Its many features merit close examination by the student.
欺骗世家
发表于 2025-3-24 03:04:07
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乏味
发表于 2025-3-24 09:20:18
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Watemelon
发表于 2025-3-24 13:21:07
The Electrical Installation Industry,Electrical installations may be considered as a practical application of electrical engineering. Supplies for the. installations come from distribution networks connected to National Grid lines, which in turn are fed from highly efficient power stations — these are administered by the Central Electricity Generating Board (C.E.G.B.).
Peak-Bone-Mass
发表于 2025-3-24 15:56:09
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CLAY
发表于 2025-3-24 22:17:05
Supplies, of these generating stations is to convert the energy inherent in coal, oil, gas or uranium into electrical energy. In nuclear power stations small amounts of uranium rod are sufficient to provide the intense heat for raising the temperature of water causing powerful steam jets to produce continuous rotation of the generator.
窒息
发表于 2025-3-25 00:01:45
Extra-Low-Voltage Supplies,ble leakage currents. Great care is also necessary to prevent short-circuits, since they may be the cause of fires. E.L.V. cables are not permitted to be drawn into the same conduit, duct or trunking partition together with cables supplying 240 V circuits, unless they are insulated for this higher voltage.