Basics of wire and cable

1, commonly used wires, cables by the use of what types of points?

A: According to the use can be divided into bare wires, insulated wires, heat-resistant wires,

shielded wires, power cables, control cables, communication cables, RF cables.

2, what kind of insulated wire?

A: There are several commonly insulated wires: PVC insulated wire, PVC insulated cord, nitrile PVC

insulation insulated cord, rubber insulated wire, agricultural underground buried aluminum core

plastic insulated wire, rubber insulated cotton yarn Textile cord, PVC insulated nylon jacket wire

, power and lighting with PVC insulated cord.

3, cable bridge for what kind of occasions?

A: The cable bridge is suitable for general industrial and mining enterprises indoor and outdoor

overhead laying power cables, control cables, can also be used for telecommunications, radio and

television departments in the indoor and outdoor erection.

4, cable accessories which?

A: The commonly used electrical accessories are cable terminal box, cable intermediate junction

box, connecting pipe and terminal blocks, steel plate wiring trough, cable tray and so on.

5, what is the cable middle connector?

A: connect the cable with the cable conductor, insulation shield and protective layer, so that th

e cable connection device, known as the cable intermediate connector.

6, what is the main electrical wiring?

A: The main electrical wiring is the power plant, substation in the main electrical equipment and

bus connection, including the main bus and auxiliary power system according to certain functional

requirements of the connection.

7, in the choice of power cable cross-section, which should comply with the provisions?

A: The selection of power cables should follow the following principles:

(1) the rated voltage of the cable is greater than or equal to the rated voltage of the power

supply system at the installation point;

(2) the cable continually allows the current to be equal to or greater than the maximum

continuous current of the supply load;

(3) core cross-section to meet the stability of the power supply system when the short-circuit

requirements;

(4) according to the length of the cable to determine whether the voltage drop to meet the

requirements;

(5) the minimum short-circuit current at the end of the line should enable the protective device

to operate reliably.

8, cross-linked polyethylene cable and oil-paper cable What are the advantages?

A: (1) easy to install, because it allows the minimum bending radius is small and light weight;

(2) is not limited by line drop;

(3) good thermal performance, allowing high operating temperature, transmission capacity;

(4) cable accessories are simple, are dry structure;

(5) operation and maintenance is simple, no oil spill;

(6) lower prices;

(7) high reliability, low failure rate;

(8) manufacturing process less, simple process, significant economic benefits.

9, fixed AC single-core cable clip What are the requirements? why?

A: The fixture should be made of iron without a piece of iron. This is because when the cable core

passes through the current, the magnetic field lines are generated around it. The magnetic field

lines are proportional to the current through the core. If the magnetic material is made of iron,

Electromagnetic induction can be seen, will produce eddy iron in the iron to heat the cable, or

even burn the cable. So you can not use iron parts for single-core AC cable fixture.

10, the following characteristics of the biggest features and advantages of heat-shrinkable cable

head accessories?

A: The biggest feature of heat shrink attachment is to replace the traditional stress cone with

stress, which not only simplifies the construction process, but also reduces the size of the

terminal of the joint, easy installation, saving time and labor, superior performance, saving

metal. Heat shrinkable cable accessories set perfusion and dry bag as a whole, the advantages of

these two accessories.

11, what should be checked before the cable laying work?

A: (1) bracket should be complete, paint complete.

(2) cable type, voltage, specifications meet the design.

(3) cable insulation is good, when the oil and paper cable seals have doubts, should be damped to

judge; buried cable and small cable should be tested by DC voltage test failure; oil-filled cable

oil samples should be qualified. Public number global electrical resources

finishing

(4) oil-filled cable oil pressure should not be less than 1.47MPa.

12, the oil and paper insulation power cable seal in doubt, how to use a more simple way to check

the cable insulation paper is damp?

A: The cable insulation paper lit or put about 150 ℃ in the cable oil inspection, no "hissing"

sound or white foam appears, indicating no moisture.

13, cable signs should be marked what? What are the requirements for writing?

A: The sign should be marked with the cable design number, cable type, specification and starting

point. The cables used in parallel should have the serial number. Requires writing clear, easy to

fall off.

14, the location of the buried cable should be set in the location?

A: at both ends of the cable, cable straight line 50 ~ 100m cable connector a few cables to change

the direction of the corner.

15, the production of cable connector with yellow wax ribbon, black glass paint, E-glass ribbon,

etc., before the construction of how to deal with drainage?

A: (1) constant temperature drying method: the insulating tape into a diameter of 25 ~ 30mm small

volume, into the 110 ~ 120 ℃ constant temperature drying oven bake 4 ~ 5h, cooling dry out, into

the dry sealed tube.

(2) oil dip drainage method: the insulation with a small volume into the temperature of

120 ~ 130 ℃ in the cable oil, from the bottom of the pot to maintain a distance of 30mm, after a

certain period of time after the oil no longer produce bubbles, In a bucket with a cable oil,

the oil level should exceed all the loaded objects and seal them.

16, what is the role of cable jacket?

A: protect the inner sheath from mechanical damage and chemical corrosion, enhance the mechanical

strength.

17, outdoor cable trench should meet the requirements?

A: The upper part of the cable trench should be slightly higher than the ground, stamped with

concrete made of the cover, the cable should be flat on the bracket, a good drain.

What is the role of the inner sheath of the cable?

A; so that the insulation will not be in contact with water, air or other objects, to prevent

insulation moisture and insulation from mechanical damage.

19, the use of steel clamp should pay attention to what?

A: Before use, be sure to check the insulation handle insulation is intact, the use of wire clamp

can not be used to cut more than the specifications allowed by the metal wire, and prohibit the

use of wire clamp instead of hammer tapping tools to avoid damage.

20, what is the insulation strength?

A: Insulation material in the electric field, when the electric field strength increases to a

certain limit will be breakdown, this lead to insulation breakdown of the electric field strength

known as the dielectric strength.

What are the advantages of cross-linked heat shrinkable cable accessories?

A: This is a new type of material, it is compared with other types of accessories with excellent

electrical performance, small size, small quality, easy installation, material support, etc.,

also has a weather resistance, anti-pollution, ability.

22, the cable conductor connection point of the mechanical strength of what?

A: The mechanical strength of the connection point is generally lower than the tensile strength of

the cable conductor itself. For fixed laying power cables, the tensile strength of the connection

point is not less than 60% of the tensile strength of the conductor itself. Public number global

electrical resources (ID: qqdqzy888) finishing

23, power cable insulation material should have what the main performance?

A: should have the following main performance:

(1) high breakdown strength;

(2) low dielectric loss;

(3) a very high insulation resistance;

(4) excellent resistance to discharge performance;

(5) has a certain degree of flexibility and mechanical strength;

(6) long-term stability of insulation performance.

24, mechanical laying cable, the traction strength of what provisions?

A: For the copper cable, when the traction head, allowing traction strength of 70N / cm; for

aluminum core cable, when the traction head, allowing traction strength of 40N / cm; if the use

of wire mesh traction, lead Cable to allow the strength of 10N / cm; lead jacket cable 40N / cm.

25, what is the provisions of the cable protection tube?

A: (1) cable need to wear protective tube laying, the pipe diameter should not be less than 1.5

times the cable diameter, concrete pipe, clay pipe, asbestos, cement pipe diameter should not be

less than 100mm;

(2) the bending radius of the cable tube should be consistent with the provisions of the

penetration of the cable bend radius;

(3) Each pipe shall not exceed a maximum of three elbows and not more than 2 at right angles.

26, how to measure the outer diameter of the cable jacket?

A: At the five points evenly distributed on the circumference of the sheath, measure the outer

diameter of the sheath and its average value, and its average outer diameter is both the outer

diameter of the sheath.

27, different cross-section of the copper cable how to connect?

A: different cross-section of the copper cable connection, can be used to open the weak back

copper pipe to tin solder connection can also be used pure copper rods according to different

cross-section requirements connected to copper pipe to crimp connection.

28, describes the 10KV cross-linked cable heat shrink production of indoor terminal process?

(1) Preparation phase: Check whether the cable accessories are complete, the model is matched,

check and confirm the cable with or without moisture, check the cable.

(2) remove the excess cable, according to the scene to determine the length of the cable.

(3) stripping the sheath.

(4) welding ground wire, the ground wire welded to the strip.

(5) filled with three fork and wrapped sealant.

(6) to install three-core branch jacket, the jacket into the roots, starting from the middle of

contraction, first to the roots, and then to the Ministry.

(7) stripping copper and outer semiconducting layer, stripping three core branching sleeve 20mm

above the copper belt, is strictly prohibited damage to the main insulation, clean the

semi-conductive layer.

(8) installation of the stress pipe, the end of the nozzle part of the hub after the heat shrink.

(9) Install the terminal block.

(10) Install the insulation tube.

(11) Install the sealing tube.

(12) nuclear phase after the installation of color tube.

29, indoor, outdoor prefabricated terminal installation steps which?

A: (1) the cable in place according to the predetermined location, fixed, clean the surface, with

reference to the instructions to remove the outer jacket, if any special needs, the outer jacket

peel length can be adjusted, respectively, by the copper, 2 sets of ground.

(2) by the outer jacket mouth to measure the size of the need to cut off the excess cable, into

the three-fold heat shrinkage to the trigeminal root by the middle of the heat shrinkage, from the

finger cover up the amount of measure (35kv 350 ~ 380mm ). Remove the excess copper (keep 20mm),

and then retain the semiconductor reservation position, crimp outlet terminal seal.

30, under what circumstances, the scene of the installation of the motor should be carried out

core inspection?

A: The motor should be inspected when one of the following conditions:

(1) the date of manufacture exceeds the manufacturer's warranty period;

(2) by visual inspection or electrical test, the quality is suspicious;

(3) open motor by the end of the inspection is suspicious;

(4) There are abnormal cases when running.

31, generators manual synchronization should have what conditions?

A: The three conditions of the juxtaposition of the generator are the voltage, frequency, phase

and operating system voltage, frequency and phase difference of the generator to be less than the

specified value.

32, bus device construction completed, what should be checked?

A: The following checks should be made:

(1) metal parts of the processing, preparation, welding screw should be consistent with the

provisions;

(2) the Department of bolts, washers, cotter and other parts should be complete and reliable;

(3) bus preparation and installation should be consistent with the provisions of the phase and the

ground to meet the electrical requirements;

(4) porcelain pieces, iron parts and glued joints should be complete, oil-filled casing should be

no oil, oil level is normal;

(5) the paint is complete, the color is correct, well grounded.

33, in the 35kv and below the power cable connector, to improve the distribution of the sheath of

the electric field there are several ways (please list five), and outlined its approach.

A: (1) bulging bells: in the lead pack cut off the edge of the lead bag pry, into a trumpet-like,

its edge should be smooth, round, symmetrical.

(2) reserved package insulation: in the lead incision to the cable core separation between the

points left a piece of insulation paper.

(3) Cut off the semiconductive paper: Cut the semiconductive paper below the bell.

(4) wrap the stress cone: with insulating tape and conductive metal material into a cone,

artificially expand the shield to improve the electric field distribution. Public number global

electrical resources (ID: qqdqzy888) finishing

(5) equipotential method: For dry-type or cross-linked polyethylene cable head, in the core of the

insulation on the surface of a section of metal band, and connected together.

(6) installation of stress control tube: for 35kv and hair under the heat shrink tube cable head,

first from the core of the copper shield end of the direction of the semiconductor to the core

insulation profile around the two-layer semiconductor belt, and then the corresponding

specifications of the stress Tube, set at the end of the copper shield, heat shrinkage forming.

34, cable bracket processing should meet the requirements?

A: (1) steel should be straight, no significant distortion, cutting error should be within the

range of 5mm, incision should be no curling, burr;

(2) the bracket should be welded firmly, no visible beak deformation, the vertical clearance

between the vertical and design deviation should not be greater than 5mm;

(3) metal stent must be anti-corrosion treatment, located in hot and humid, salt, fog and

chemical corrosion area, should be designed for special anti-corrosion treatment.

35, list the cable racks you are familiar with.

A: Tailor-type E-frame, assembly E-frame, bridge cable rack, cable tray, hook-type bracket,

a single cable bracket.

36, laying the cable should meet the requirements?

A: The following requirements should be met:

(1) safe operation, as far as possible to avoid a variety of external damage, improve the

cable line power supply reliability;

(2) economic aspects, from the investment in the most considerable aspects;

(3) construction, the cable line path must be easy to turn the workers and after the operation

of the maintenance.

37, the production of cable terminal or middle of the insulation material which?

A: There are insulation, insulation, insulation, insulation gloves, insulating resin.

38, a brief description of the general operation of the cable head procedures.

A: (1) preparation before preparation: including ○ 1 read the installation instructions; ○ 2 to

see the scene; ○ 3 preparation; ○ 4 cable test taps; ○ 5 pre-production test.

(2) joint production process: including ○ 1 cut off the excess cable; ○ 2 cable protection layer

stripping; ○ 3 conductor connection; ○ 4 wrapped around insulation (or shrink pipe);

○ 5 installation connector shell; ○ 6 perfusion insulation Agent, and the like.

(3) after the production of electrical testing.

39, cable protection tube processing should meet the requirements?

A: (1) the mouth should be flattened assassination and sharp corrugated angle, the mouth should

be made horn.

(2) the cable tube in the bending, there should be no cracks and significant concave phenomenon,

the degree of bending should not be greater than the tube diameter of 10%; cable tube bending

radius should not be less than the minimum allowable bending radius of the cable The

(3) metal pipe should be coated in the appearance of anti-corrosion paint or leaching table,

galvanized pipe zinc layer peeling should also be coated with anti-corrosion paint.

40, the cable arrangement meet the requirements?

A: (1) power cables and control cables should not be configured on the same shelf.

(2) high and low voltage cables, strong and weak electric control cable should be layered

according to the order configuration, the general situation should be from top to bottom, but

with more than 35kv high voltage cable into the cabinet, to meet the bending radius,

Configuration.

Eric Xie

Tel: +86 15988295936

SKYPE: ericxie123@outlook.com

Whatsapp: +8615988295936

Wechat: +8615988295936

Email: sale@benoelectric.com

Website:www.benoindustry.com

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