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NABTEB ELECTRICAL INSTALATION COMPLETE ANSWER.

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NABTEB ELECTRICAL INSTALATION COMPLETE ANSWER.

(Number 1)

(1a)
(i)Low voltage
(ii)medium voltage
(iii)high voltage
(iv)Ultra high voltage

(i)Low voltage is normally used for doorbells, garage door opener controls, heating and cooling thermostats, alarm system sensors and controls, outdoor ground lighting, household and automobile batteries

(ii)Medium-voltage cables are commonly used in mobile substation equipment, for distribution of power in industrial settings and in mining to supply power to drills, shovels, haulers, etc

(iii)High voltage is used in electrical power distribution, in cathode ray tubes, to generate X-rays and particle beams, to produce electrical arcs, for ignition, in photomultiplier tubes, and in high-power amplifier vacuum tubes, as well as other industrial, military and scientific applications.

(iv)Ultra-high-voltage electricity transmission (UHV electricity transmission) has been used in China to transmit both alternating current (AC) and direct current (DC) electricity over long distances separating China’s energy resources and consumers.

(1b)
Final subcircuit is defined as an outgoing circuit, connected to a distribution board, and intended to supply electrical energy direct to current-using apparatus,either directly or through socket outlets or fused spur boxes.


(Electrical Installation)

(NUMBER 5)

(5a)
Armoured cable is a power and auxiliary control cable, designed for use in mains supply electricity. Used for underground systems, cable networks, power networks, outdoor and indoor applications, and cable ducting.

(5b)
Termination of cable is the connection of the wire or fiber to a device, such as equipment, panels or a wall outlet, which allows for connecting the cable to other cables or devices.

(5c)
(Choose Any four)
(i)Trenching Tools
(ii)Ploughing tool
(iii)Boring tools
(iv)Conduit
(v)Cable Pulling Devices


 

(4a)
In soldering of metals, flux serves a threefold purpose: it removes any oxidized metal from the surfaces to be soldered, seals out air thus preventing further oxidation, and by facilitating amalgamation improves wetting characteristics of the liquid solder.

(4bi)
Brazing: Brazing in cable joints is a metal-joining process in which two or more metal items are joined together by melting and flowing a filler metal into the joint, the filler metal having a lower melting point than the adjoining metal. A brazed joint is made in a completely different manner from a welded joint.

(4bii)
Soldering: Soldering in cable joints is a process in which two or more items are joined together by melting and putting a filler metal (solder) into the joint, the filler metal having a lower melting point than the adjoining metal. Soldered joints is one of the most popular methods of connecting metal components with the use of a low melt alloy solder


 

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