Electrical cable common manual, more comprehensive no

1. Some national standards, industry standards and professional standard codes are commonly used in mainland China

Codename	Meaning
GB GB/T GBn GJB GBJ	National mandatory standards National recommended standards National internal standards National military standards National Engineering Construction Standards
/T DL JB SJ YD CSBTS/TC	Mandatory industry standards Industry recommended standards Power industry standard Machinery industry standards (including machinery, electricians, instrumentation, etc.) Electronics industry standard Ministry of Posts and Telecommunications Standards National Wire and Cable Standard Technical Committee Standard

2. Commonly used international standards and foreign standard codes

code name	Meaning	code name	Meaning
ISO	International standards	IS	Indian standards
ISO/DIS	Draft international standards	ISIRI	Iranian standards and industrial research institute standards
ANSI	U.S. National Standard	HE	Japanese Industry Standard
AISI	American Iron and Steel Institute standards	KS	Korean Industry Standard
ASME	Standards of the American Society of Mechanical Engineers	MS	Malaysian Standards
ASTM	American Society for Materials and Testing standards	NB	Brazilian standards
BHMA	Standards of the American Association of Small Hardware Makers	NBN	Belgian standards
FS	U.S. Federal Specifications and Standards	NCh	Chilean standards
THOUSAND	U.S. Military Standards and Specifications	NEN	Dutch standards
SAE	Standards of the American Society of Motor Engineers	NF	French standard
HIVE	Standards of the American Institute of Insurers	ISO/R	International Organization for Standardization Recommended Standards
AS	Australian standards	IEC	International Electrotechnical Commission
BS	British Standard	NOR	Indonesian standard
CSA	Canadian Standards	NAME	Official standards for Mexico
FROM	German standard	FOR EXAMPLE	Portuguese standards
DS	Danish standards	NS	Norwegian standards
ELOT	Greek standards	NSO	Nigerian Standards
IT	Egyptian standard	NZS	New Zealand Standards
IRAM	Argentine standard	ONORM	Austrian standards
I.S.	Irish Standards	PN	Polish standards
SABS	South African standard specifications	PS	Pakistani standard
SFS	Standards of the Finnish Standards Institute	PS	Philippine Standards
YES	Israeli standards	PTS	Philippine Trade Standards
SIX	Swedish standard	STAS	Romanian standard
SLS	Sri Lankan standard	TCYN	Vietnamese standards
SNS	Syrian standards	TIS	Thai standard
SN	Swiss standards	TS	Turkish standard
ONESELF	Iranian standards	ONE	Spanish standards
S.S.	Singapore Standard	PLAIN	Italian standards
ROCT	CIS national standards	ROCTP	CIS national standards

3. Letter symbols and their meaning

letter	Expression of meaning
A	(Poly)ammonia (ester), ampere (packing), aluminum plastic sheath
B	Flat, semi-, knitted (woven), pump, cloth, (poly) styrene (ethylene), glass (glass fiber), complement, flat (parallel) (i.e. flat)
C	Vehicle, alcohol, mining (excavator), porcelain, heavy (type), marine, (storage) pool, magnetic, charging, compensation (yellow wax) silk, vinegar (acid film), self-supporting
D	With, (not) drip, lamp, electricity, (cold) jelly, butyl (based eraser), plating, antioxidant
And	Two (layer), wild (outer), symmetry (structural code)
F	(Poly4) fluorine (ethylene), phased, non-(flammable), flying (machine), foam polyethylene (YF)
G	Steel, groove, silicon, modified (paint), pipe, high (pressure)
H	Combination (gold), ring (oxygen paint), welding, flower, communication cable (application code), H (type), phased shielding structure code
J	Twisting, adding (strong), adding (thickness), sawing, bureau (using), crosslinking
K	(True) Void, Card (Pron), Control, Armor, Hollow
L	Aluminum, furnace, wax (grams), asphalt (green), anti-lightning, phosphorus
M	Cotton (yarn), hemp, mother (thread), cap, membrane
N	Viscous (sexual), mud (carbon), resistance (nitry), nylon
Or	Coaxial (structural code)
P	Row, screen (mask), distribution (wire), signal cable (application code)
Q	Lead (lead), paint, lead, light (type), gas, steam (car), (high) strength (polyvinyl alcohol acetal)
R	Soft, human (made), daily use, heat (chemical)
S	Brush, wire, injection (frequency), double, plastic (steel sheath)
T	Copper, antimony, special, through, elevator, probe
In the	Minerals (asbestos), mining
In	V (PVC)
In	Object (reason), wrinkle sheath, none (magnetic), warm
X	Rubber (force cable), polyamide, rubber (insulation)
And	Hard, round, oil, oxygen, resistant (oil), mobile, polyethylene, (electrical) pressure
With	(Poly)grease, paper, electric drill, medium size, synthesis (combination)

4. Cable sheath model and its meaning

Model	Name	Applicable objects
02	PVC sheath	Aluminum sleeve, lead sleeve, wrinkled aluminum sleeve, wrinkled steel sleeve protection
03	Polyethylene sheath	Aluminum sleeve, lead sleeve, wrinkled aluminum sleeve, wrinkled steel sleeve protection
20	Bare steel belt armored	The lead sleeve is protected against pressure
21	Steel belt armored fiber outer quilt	The lead sleeve withstands pressure and is resistant to corrosion
22	Steel strip armored PVC sheath	Aluminum sleeves, lead sleeves, wrinkled aluminum sleeves, non-metal sleeves withstand pressure and corrosion protection
23	Steel belt armored polyethylene sheath	Aluminum sleeves, lead sleeves, wrinkled aluminum sleeves, non-metal sleeves withstand pressure and corrosion protection
30	Bare steel wire armor	Metal and non-metal sleeves withstand tension
31	Fine round steel wire armored fiber outer quilt	The lead sleeve is anti-corrosion resistant to tensile forces
32	Fine round steel wire armored PVC sheath	Metal and non-metal sleeves are protected by tensile forces
33	Fine round steel wire armored polyethylene sheath	Metal and non-metal sleeves are protected by tensile forces
40	Bare thick round steel wire armor	Metal and non-metal sleeves are protected by tensile forces
41	Coarse round steel wire armored fiber outer quilt	Metal and non-metal sleeves are protected by tensile forces
42	Coarse round steel wire armored PVC sheath	Metal and non-metal sleeves are protected by tensile forces
43	Thick round steel wire armored polyethylene sheath	Metal and non-metal sleeves are protected by tensile forces
102	Copper strip radially reinforced PVC sheath	Metal and non-metal sleeves require non-magnetic pressure protection
103	The copper strip is radially reinforced with polyethylene sheath	Metal and non-metal sleeves require non-magnetic pressure protection
202	Stainless steel with radially reinforced PVC sheath	Metal and non-metal sleeves require non-magnetic pressure protection and corrosion protection
203	Stainless steel with radial reinforced polyethylene sheath	Metal and non-metal sleeves require non-magnetic pressure protection and corrosion protection
141	Copper strip radially reinforced coarse steel wire armored fiber outer cover	Metal and non-metal sleeves require non-magnetic pressure protection and corrosion protection
241	Stainless steel with radially reinforced coarse steel wire armored fiber outer cover	Metal and non-metal sleeves require non-magnetic pressure protection and corrosion protection
441	Double thick round steel wire armored fiber outer quilt	Metal and non-metal sleeves require non-magnetic pressure protection and corrosion protection
2441	Steel belt radially reinforced double thick round steel wire armored fiber outer quilt	Metal and non-metal sleeves require non-magnetic pressure protection and corrosion protection

5. Commonly used cable structure calculation

1) Round single line: Round single line is a single circular wire that does not cover other metal layers.

2) Area S of a single line of a circle

P

S = —— d2（mm2）

4

3) Circular single line perimeter L

L = πd (mm)

4) The weight of the round single line

P

W = —— d2 ρ= Sρ(kg/km)

4

where: ρ - material density (g/cm3)

5) Commonly used round single line weight

Materials used	Material density (g/cm3)	Weight (kg/km)
Aluminium and aluminium alloys	2.7	2.121d2
copper	8.89	6.928 d2
Steel (iron)	7.8	6.126 d2

6) Flat wire: Flat wire is used for rectangular conductor core and cable armor of the electromagnetic wire class.

S = from — [4r2-πr2]

= from — 0.858 r2 (mm2)

Wherein: a - thickness (mm);

b - width (mm);

r - Corner radius (mm).

7) The perimeter L of the flat line

L = 2(a + b)— (8r — 2πr)

8) Flat line size deviation

Dimensional deviation of the narrow side a of the flat line

Nominal size a(mm)	Deviation (mm)
a≤3.15 3.15< a≤6.30 6.30< a≤7.10	±0.03 ±0.05 ±0.07

Dimensional deviation of the flat line width b

Nominal size b(mm)	Deviation (mm)
b≤3.15 3.15<b≤6.30 6.30< b≤12.50 12.50< b≤16.00	±0.03 ±0.05 ±0.07 ±0.09

Flat line fillet radius dimensional deviation range

Nominal size a(mm)	Corner radius r(mm)
Nominal	Bias (%)
a≤1.00 1.00<a≤1.60 1.60<a≤2.44 2.44< a≤3.55 3.55< a≤6.00 6.00< a≤7.10	a/2 0.5 0.65 0.80 1.00 1.20	±25

9) The outer diameter of the central layer composed of 1 to 5 single lines

The number of single-line roots is Zo	Outer Diameter Do(mm)	Outer diameter ratio Mo(Do/d)
1.00	Do = d	1.00
02	Do = 2d	02
03	Do = 2,154d	2.154
4	Do = 2,414d	2.414
5	Do = 2.7d	2.7

10) Ordinary strand cross-sectional area S and weight W

S = (p/4)d2Z(mm2)

Where: d - single line diameter;

Z - The total number of roots of a single line.

W = SKmμ= (p/4)d2ZKmr(kg/km)

Wherein: Km - the average stranding coefficient of the stranded wire;

ρ - the density of the material for stranding (g/cm3).

11) Compound strand: The complex strand is made of multi-stranded bundle or ordinary stranded wire with regular stranding, so the outer diameter is round.

12) Complex strand outer diameter D complex 1

When the rubber wire of the compound strand is stranded:

D复 =(D复/ D股)(D股/d)d

=(D复/d)d = M复·d

When the rubber wire of the compound strand is stranded:

D复 =(D复/ D股)(D股/d)d

=(D复/d)d = M复·d

When the glue wire of the compound strand is bundled:

D复 =(D复/ D股)(D股/d)d·k

=(D复/d)d ·k = M复·d·k

Wherein: D complex / D strand - the ratio of the outer diameter of the complex strand to the outer diameter of the strand;

D complex/d - the ratio of the outer diameter of the strand to the diameter of a single wire;

d - single line diameter;

M复——D复/d;

K - The cable adjustment factor.

13) Compound strand filling system η complex

复 =h1h2×100(%)

wherein: η1η2 - the filling coefficient (%) when stranded and rewound, respectively.

14) Weight of the compound strand W complex

W复 =W股 Z股 K复 (kg/km)

Where: W strands - the number of strands in the compound strand;

K complex - the twisting coefficient of the complex stranding.

15) Hollow core: generally used for high-voltage cable conductive wire core, internal through insulator (such as oil-filled cable insulating oil).

16) The single circular wire constitutes the outer diameter and weight of the hollow core

The outer diameter D is calculated as follows:

D = D支 + 2nd +2t (mm)

Formula: D branch - inner brace screw tube outer diameter (mm)

n - the number of stranded layers of a single copper wire

d - Copper single wire diameter (mm)

t - Shield thickness (mm)

Weight W is calculated as follows:

W = W支 + W铜 + W屏 (kg/km)

W铜 =(π/4)d2ZKmρ (kg/km)

Formula: W branch - inner support spiral tube weight;

W Copper – Copper wire weight;

W screen - shield layer weight.

17) The outer diameter and weight of the Z or bowed single-line hollow core

The outer diameter D is calculated as follows:

D = Do + 2t = To + 2(t1 + t2) (mm)

In the formula: Do - the aperture of the type line after stranding (mm);

t - the total thickness of the cable after stranding;

t1 – Z-shaped line thickness (mm);

t2 – bow line thickness (mm);

18) Compression strand and tight pressure core: The compression strand for overhead wire and the round tight pressure core for cable conduction core, its structure, stranding and compacting process and cross-section shape are exactly the same. Their outer diameter is smaller than that of ordinary strands.

19) Cross-sectional area S of compression stranded wire and tight pressure core

p 1

S = — d2 C — (mm2)

4 m

Where: d - single line diameter;

z - the number of single-line roots;

μ - The coefficient of extension of a single line when pressing, taking the following empirical values:

The cross-section is 25~70mm2, the μ=1.05; the cross-section is 95~120mm2, the μ=1.035; the cross-sectional ≥ is 150mm2, and the μ=1.04.

20) The weight of the compression strand and the tightly pressed core W

p 1

S = — d2 Z — Kmρ (kg/km)

4 m

where: Km - the average winch coefficient;

ρ - material density (g/cm3)

If the stranded wires are made up of single lines of different diameters, the product of d2 Z should be calculated separately.

21) Solid insulation: This is a common insulation layer, which includes extruded or longitudinal rubber insulation, extruded or coated plastic insulation and paint film.

22) Circular single wire core insulation layer: This is the simplest form of insulation layer, this form is mainly used for general insulated wires, enameled round wires, communication wires and cables, signal and control cables, etc.

Insulation outer diameter D

D = d + 2t (mm)

Wherein: d - conductor diameter (mm);

t - thickness of the insulation layer (mm);

Insulation cross-sectional area S

S = π（d + t）t (mm2)

Insulation layer weight W

W =π(d + t)tρ (kg/km)

Wherein: W - weight of solid paint film (kg/km);

ω - solids content(%)

Polyethylene 0.92-0.95 POLYVINYL CHLORIDE 1.35-1.4

23) The outer diameter and material weight of the steel belt after armoring

D = D1 + 4t — 1 (mm)

W =π(D1 + 2t — 1)2tρk (kg/km)

Formula: D1 - Outer diameter of steel belt armored front half product (mm)

t - Steel strip thickness (mm)

ρ - steel belt density (g/cm3)

k - the clearance coefficient of the steel belt.

6. The variety, characteristics and uses of enameled wire

category	The product name	Advantages	limitations	Main uses
Polyester enameled wire	Grade 130 thin lacquered polyester enameled copper wire Grade 130 thick lacquered polyester enameled round copper wire	1, in the dry, wet and softening conditions with excellent voltage breakdown performance; 2, QZN type enameled wire can be self-adhesive into shape.	1, poor water resistance (for sealing motor or electrical appliances should pay attention to); 2, and polyethylene, neoprene and other polymer compounds are not compatible; 3, thermal shock performance is general.	Windings of general-purpose small and medium-sized motors, dry-type transformers and coils of electrical instruments.
155 grade thin enameled polyester enameled copper wire Grade 155 thick lacquered film polyester enameled round copper wire
Thermally bonded or solvent bonded film polyester enameled round copper wire
Acetal enameled wire	Grade 120 film acetal enameled round copper wire Grade 120 thick film acetal enameled round copper wire Grade 120 extra thick film acetal enameled round copper wire	It has thermal shock, scratch resistance and water resistance	The paint film is easily broken when it is wound (it must be heated at 120 ° C for more than 1 hour before impregnation to eliminate stress)	General purpose small and medium-sized motors, micro motor windings and oil-immersed transformer coils, electrical instrumentation coils
Polyurethane enameled wire	Grade 130 thin enamel polyurethane enameled round copper wire Grade 130 thick enamel polyurethane enameled round copper wire Thermally bonded or solvent bonded thick enamel polyurethane enameled round copper wire	1, low dielectric loss under high-frequency conditions; 2, can be directly welded without scraping off the paint film; 3, good colorability, can be made of different colors of enameled wire, easy to identify	1, poor overload performance; 2, thermal shock and scratch resistance is average.	High-frequency coils, TV coils and cable coils, and micro coils for instrumentation are required to have stable Q values
Polyester imine enameled wire	Grade 180 thin enamel polyester imide enameled round copper wire Grade 180 thick enameled polyester imine enameled round copper wire Grade 180 thin enamel polyester imide enameled flat copper wire Grade 180 thick enameled polyester imine enameled flat copper wire	1, in the dry, wet and softening conditions with excellent voltage breakdown performance; 2, thermal shock performance is good.	1, in the water-containing sealing system is easy to hydrolysis; 2, and polyvinyl chloride, neoprene chlorine-containing polymer materials are incompatible.	Windings of motors, dry-type transformers and coils of electrical instrumentation in high-temperature motors and refrigeration units
Polyimide enameled wire	Grade 220 thin enamel polyimide enameled round copper wire Grade 220 thick enamel polyimide enameled round copper wire Grade 220 thin enamel polyimide enameled flat copper wire Grade 220 thick enamel polyimide enameled flat copper wire	1, excellent heat resistance; 2, softening breakdown and thermal shock excellent; 3, excellent resistance to low temperature radiation performance; 4, solvent resistance and chemical corrosion resistance.	1, scratch resistance is general; 2, poor alkali resistance; 3, in the aqueous sealing system is easy to hydrolysis; 4, the paint film is subjected to winding is easy to produce cracks.	High temperature resistant motor windings, dry-type transformers, sealed relays and electronic components.
Composite layer enameled wire	Grade 180 thin enamel polyester imide/polyimide composite enameled round copper wire Grade 180 thick paint film polyester imide/ polyimide composite enameled round copper wire Grade 180 extra thick lacquer film polyester imide/ polyimide composite enameled round copper wire Grade 200 thin enamel polyester imide/polyimide composite enameled round copper wire 200 grade thick lacquer film polyester imide/ polyimide composite enameled round copper wire 200 grade thin paint film polyester imide/ polyimide composite enameled flat copper wire 200 grade thick paint film polyester imide/ polyimide composite enameled flat copper wire	1, excellent heat resistance; 2, softening breakdown and thermal shock is excellent; 3, low temperature radiation resistance is excellent.	1, in the water-containing sealing system is easy to hydrolysis; 2, and polyvinyl chloride, neoprene chlorine-containing polymer materials are incompatible.	Windings of motors for cooling devices and high temperature motors, dry-type transformers and electrical instrumentation
Other enameled wires	Oil-based enameled wire	1, the paint film is uniform; 2, the dielectric loss is tangent	1, poor scratch resistance; 2, poor solvent resistance.	Medium and high frequency coils and coils for instrumentation appliances
Non-magnetic polyurethane Enameled round copper	1, the iron content in the enameled wire is extremely low, and the interference effect in the induced magnetic field is minimal; 2, the medium loss is small at high frequency; 3, no need to peel off the paint film can be welded.	Not recommended for use under overload conditions.	Coils for precision instruments and appliances, such as DC mirror-type flow detectors, magnetic flux meters, and coils for seismic measurement

7. The variety, characteristics and use of special winding wire

The product name	Features	Main uses
Heat resistance(°C)	Advantages	Limits
Paper insulated enameled transposition wires	105	1, no cycle current, the eddy current loss in the coil is small, can improve the current density; 2, simplify the winding coil process; 3, than the paper bag trunk full rate is high.	The bending performance is poor, and the diameter of the coil core and the bending diameter when used should not be less than 6H2	Coils for large transformers
Polyethylene insulated nylon sheath water resistant winding wire Polyethylene insulated water-resistant winding wire Cross-linked polyethylene absolute Rim nylon sheath water resistant winding wire	70 70 90	1, good water resistance, long-term work underwater, stable insulation resistance; 2, nylon sheath can strengthen mechanical protection performance.	The slot full rate is low	Suitable for various forms of water-filled motor windings
300MW generator set with insulated hollow flat copper wire	155	1, hollow flat wire as hydrogen refrigeration, high material requirements; 2, mechanical strength and good adhesion performance.	The insulation line has a large hardness and is difficult to construct	Dedicated 300MW generator set stator winding set

8. The code names of each part of the product model of wire and cable for electrical equipment and their meaning

symbol	Meaning	symbol	Meaning	symbol	Meaning
A	Install the cable	X	rubber	ZR	Flame retardant
B	Electrical cables	ST	Natural silk	P	shield
F	Aviation lines	HERSELF	Double wire pack	R	soft
And	Industrial Mobility	VZ	Flame retardant PVC	S	Twisted pair
Electrical wiring	B	polypropylene	B	parallel
N	Agricultural lines	In	polyvinyl chloride	D	Band shape
HR	Telephone cord	H	Rubber sleeve	T	Special
HP	Telephone wiring	And	polyethylene	In	Weatherable and oil resistant
SB	Wires for radio installations	B	Braided sleeve
In	polyvinyl chloride	L	Varnish (wax g)
F	Fluoroplastics	N	nylon
And	polyethylene	CS	Nylon wire

9. General rubber plastic wire use requirements and structural characteristics

Use features

Structural features

1. Scope of application: AC rated voltage 450/750V and below power, lighting, electrical devices, instrumentation and telecommunications equipment connection and internal installation line. 2. Laying occasions and methods: indoor open laying and communication channels, tunnels along the wall or overhead laying; outdoor overhead laying, iron pipe or plastic pipe laying, electrical equipment, instruments and radio devices, are fixed laying; plastic sheathed wires can be buried directly in the soil. 3. General requirements: economical and durable, simple structure. 4. Special Requirements: 1) When laying outdoors, due to the influence of conditions such as sunlight, rain and ice, it is required to be resistant to the atmosphere, especially to sunlight aging; there are cold tolerance requirements in cold areas; 2) In use, susceptible to external force damage or flammability, and contact with oil should be through the pipe in many occasions; when the pipe is worn, the wire is subjected to a large tensile force, and there is a possibility of scratching, lubrication measures should be taken; 3) As the internal use of electrical equipment, when the installation position is small, there should be a certain degree of flexibility, and the insulation wire core color separation is required, and the corresponding connector terminals and plugs should be cooperated to make the connection convenient and reliable; for the occasion of anti-electromagnetic requirements, shielded wires should be used; 4) For occasions with high ambient temperature, sheathed cables should be used; heat-resistant cables should be applied for special high temperature occasions.

1, conductive wire core: as a power, lighting and electrical equipment internal installation, the priority to use copper core, for large-section wire should be used tight pressure core; fixed installation of the conductor generally use class 1 or class 2 conductor structure. 2, insulation: insulation materials generally use natural styrene-butadiene rubber, polyvinyl chloride, polyethylene, nitrile polyvinyl chloride composite and other four kinds; heat-resistant wire using temperature-resistant 90 °C polyvinyl chloride. 3, sheath: sheath materials generally have polyvinyl chloride, cold polyvinyl chloride, anti-ant polyvinyl chloride, black polyethylene, chloroprene rubber and other five kinds. Black polyethylene and chloroprene sheathed wires should be used for special hardy and outdoor overhead laying. In environments with external forces, corrosion, moisture, etc., rubber or plastic sheathed wires can be used.

10. General rubber plastic soft wire use requirements and structural characteristics

Use features

Structural features

1. Scope of application: mainly suitable for the connection of medium and light mobile appliances (household appliances, power tools, etc.), instrumentation, power lighting; the working voltage is AC 750V and below, most of which are AC 300C grade. 2, because the product should often move, bend, twist, etc. when used, it is required that the wire is soft, the structure is stable, it is not easy to kink, and has a certain wear resistance; the plastic sheath cable can be laid directly in the soil. 3, the grounding wire is yellow and green two-color wire, other cores in the cable are not allowed to use yellow and green core. 4. When the power connection line for electric heating appliances is used, the braided rubber insulated soft wire or rubber insulated soft wire should be used as appropriate. 5, the requirements of the structure is simple and lightweight.

1, conductive wire core: the use of copper core, the structure of the soft type, the system of multiple single wire harness twisted; soft wire conductor generally adopts the 5th or 6th class conductor structure. 2, insulation: insulation materials generally use natural styrene-butadiene rubber, PVC or soft polyethylene plastic. 3. The pitch multiple of the cable is small. 4. The outer protective layer is woven with cotton yarn to avoid overheating and scalding the insulation layer. 5. In order to facilitate the use and simplify the production process, the three-core balanced structure is adopted, which can save production man-hours and improve production efficiency.

11. Shielded insulation wire and cable use requirements and structural characteristics

Use features

Structural features

1, shielded wire performance requirements: basically the same as the requirements of unshielded similar wires. 2. Because it meets the requirements of the equipment for shielding (anti-interference performance), it is generally recommended for medium-level electromagnetic interference occasions; plastic sheathed cables can be laid directly in the soil. 3. The shielding layer should be able to have good contact with the connecting device or ground at one end, and require the shielding layer not to be loosened, constantly silked and not easy to be scratched by external objects.

1, conductive wire core: some occasions allow tin plating; 2. The surface covering density of the shielding layer should meet the standard or meet the user's requirements; the shielding layer should be woven or wound with tinned copper wire; if the shield should be squeezed and sheathed, the shielding is allowed to be woven or wound with soft round copper wire. 3. In order to prevent internal interference between wire cores or wire pairs, each wire core (or wire pair) can be produced with a separate phase shielding structure.

12. Requirements and structural characteristics of shielded insulated wire and cable

Use features

Structural features

1, the scope of application of universal rubber cable is very wide, where the requirements of mobile connection of various electrical equipment can be applied, including the industrial and agricultural departments used in the electrical and mobile equipment connection. 2. According to the size of the cable section and the ability to accompany the mechanical external force, it is divided into three types: light, medium and heavy. These three types of products have the requirements of softness and easy bending, but the soft requirements of light cables are high, and they should be lightweight, small in size, and cannot withstand strong mechanical external forces; medium-sized cables have certain flexibility and can withstand considerable mechanical external forces; heavy cables have high mechanical strength. 3. The cable sheath should be tight and strong and have a certain roundness. YQW, YZW, YCW cable is suitable for field use (such as searchlights, agricultural electric plows, etc.), should have good resistance to sunlight aging performance.

1, conductive wire core: the use of copper soft wire harness stranding, the structure of the soft type, large cross-section surface allows paper wrapping, improve bending performance. 2. The insulation adopts natural benzene-butadiene rubber, and the aging performance of the insulation is good. 3. The eraser of outdoor products adopts neoprene glue or mixed rubber formula based on neoprene glue.

13. Requirements and structural characteristics of mining cables

Use features

Structural features

1, the scope of application is very wide, mainly used in the mining industry surface and underground equipment special cable products, involving mining electric drilling cable, communication and lighting equipment cable, mining and transportation cable, cap lamp cable, underground mobile substation power power cable. 2, the use of mining cable environment is very complex, the working environment is very harsh, gas and coal dust accumulation, easy to cause explosion, so the cable safety requirements are very high. 3, the product should often move, bend, twist, etc. when using, so it requires the wire to be soft, the structure is stable, it is not easy to kink, etc., and has a certain need to grind.

1, conductive wire core: the use of copper core, the structure of the soft type, the system of multiple single wire harness twisted: soft wire conductor generally adopts the 5th or 6th type of conductor structure. 2, insulation: insulation materials generally use eraser. 3. The pitch multiple of the cable is small. 4. More products use metal braiding, uniform electric field, improve the sensitivity display of insulation conditions. 5. There is a thick outer sheath, and the color separation treatment is carried out under the mine at the same time, so that the construction personnel can understand the different voltage levels used by the cable.

14. Requirements and structural characteristics of seismic cables

Use features	Structural features
1, land use: small outer diameter, light weight, soft, wear-resistant, bending resistance, weather resistance, water resistance, anti-interference, good insulation performance, easy to identify the core, complete sets of tissue convenient.	Wires are thin insulated with soft structures or enameled wires, wire cores are twisted and color-separated, insulation is made of materials with small dielectric coefficients, and sheaths are made of polyurethane materials.
2, aviation: non-magnetic, tensile resistance, small outer diameter, light weight.	Copper conductor
3, for marine use: good sound transmission, good water resistance, moderate floating, can float under the water to a certain depth, tensile resistance, bending resistance, anti-interference good.	Special sound transmission material, reinforced wire core or armored foam inner sheath to adjust the float.

15. Requirements and structural characteristics of drilling cable

Use features	Structural features
1, load detection cable: small outer diameter is usually less than 12mm; length long, more than 3500m single length supply; oil and gas resistance, water pressure resistance 120MPa (1200 times atmospheric pressure); high temperature resistance: more than 100 °C; anti-interference, tensile force: more than 44KN; wear-resistant, hydrogen sulfide gas; all armored steel strands in the fracture, not scattered, otherwise it will cause waste wells.	1, the conductor with soft structure, and tin plated; 2, insulation with high temperature resistant polypropylene, eppropylene rubber or fluoroplastics; 3, shielding with semi-conductive materials; 4, armor with high-strength galvanized steel wire; 5, with special manufacturing technology.
2, perforated cable: hole cross-sectional area and tensile force, wear-resistant, vibration, not loose.	1, the conductor with medium soft structure; 2, insulation with polypropylene, eppropylene rubber or other high-temperature resistant materials; 3, the conductor, insulation, armor size is correct.
3. Coalfield, non-metallic, metallic, geothermal, hydrological, underwater and other survey cables.	1, strengthen the core, inner armor; 2, the conductor is soft copper wire; 3, insulation with ordinary eraser; 4, sheathed chloroprene eraser; 5, special cases with metal or non-metallic armor; 6, underwater cable to use coaxial cable; 7, the comprehensive detector should have power, communication and other functions.
4, submersible pump cable: tubing outer diameter is small, requiring small external size of the cable; well depth increase, power, requires insulation high temperature resistance, high pressure, structural stability; good electrical properties, good insulation performance, small leakage current; long life, stable structure, reusability; good mechanical properties.	1, small and medium-sized tubing, take the use of flat cables, to ensure small dimensions; the conductor uses solid, large cross-section: the use of stranded conductors, round cables; 2, the lead cable core with polyimide - fluorine 46 sintered wire, ethylene propylene insulation; power cable with ethylene propylene, cross-linked polyethylene heat-resistant insulation; 3, sheath with oil-resistant neoprene rubber, chlorosulfonated polyethylene and other oil-resistant high-temperature materials, lead sheaths, etc.; 4, the use of chain armor; 5, anti-halogen structure, in the bare armor plus anti-halogen sheath.

16. Elevator cable use requirements and structural characteristics

Use features

Structural features

1. The cable should be hung freely before use, fully retracted, and the cable reinforcement core should be fixed while withstanding the tension; 2, multiple cables should be laid in rows, in operation, the cable moves up and down with the elevator, moving and bending frequently, requiring softness and good bending performance; 3. The cable is laid vertically, requiring a certain tensile strength; 4, the working environment has oil pollution to prevent fire, cable requirements do not extend combustion; 5, the requirements of small outer diameter, light weight.

1. The use of 0.2mm round copper single wire harness stranding, insulation and conductor between the wrapping of the isolation layer, into the cable in the same direction to increase the softness, bending performance of the cable; 2, the cable to increase the cable reinforcement core, to withstand mechanical tension, reinforcement core using nylon rope, wire rope and other materials to increase the tensile strength of the cable; 3. YTF type cable adopts neoprene-based sheath to improve the weather resistance and non-delay of the cable.

17. Control signal cable requirements and structural characteristics

Use features

Structural features

1. Since the control signal cable is used to control the measurement system, the cable is required to work safely and reliably; 2. Generally for fixed laying, but the cable is connected to the equipment Requires softness and the ability to withstand multiple bends without breaking; 3. The working voltage is 380V and below, and the voltage of the signal cable is lower; 4, the signal cable working current is generally below 4A, the control cable as the main equipment circuit when the use of the current is slightly larger, so you can choose the cross-section according to the line voltage drop and mechanical properties.

1, the wire using copper core, fixed laying using a single structure to add 7 stranded structures; moving using 5 types of soft conductor structure to meet the soft, bending resistance; 2, insulation mainly using polyethylene, polyvinyl chloride, natural styrene butadiene glue and other insulation; 3, the insulation core should be reversed into a cable, so that the structure is more stable; for the field cable into a cable, the use of nylon rope filling, increase tensile resistance, and co-directional cable can increase soft performance; 4, sheath: mainly using polyvinyl chloride, neoprene rubber and nitrile polyvinyl chloride composite.

18. Requirements and structural characteristics of DC high voltage cable

Use features

Structural features

1, Zhihan high-voltage cable application range is very wide, is currently mainly used in a variety of industries in the new technology equipment, such as X-ray machine, electron beam processing, electronic bombardment furnace electronic gun, electrostatic spray paint, etc., such products are generally the power of the power supply is larger, so the filament current through the cable is also relatively large, up to dozens of amperes; voltage from 10KV to 200KV range; 2. Most of the cables are fixed and laid, and they are generally not direct with human beings Contact; 3, the cable transmission energy is larger, to consider the cable thermal cable allowable working temperature; 4, some equipment use medium frequency short time discharge, cable It must withstand 2.5-4 times the voltage, so consider sufficient electrical strength; 5. Because various equipment has not yet been standardized and serialized, the same type of equipment, the working voltage between the filament, the working voltage between the filament core and the gate core are not the same, so they should be selected separately.

1, conductive wire core: the wire core is generally 3 cores, there are also 4 cores or 5 cores; 2, 3 core cables are generally two filament heating cores, a control wire core; the wire and shielding are subjected to DC high voltage; 3, 3 core cables have two forms: one is similar to X cable, using split phase insulation and then packaged semi-conductive layer, high-voltage layer; the other will be the control core as the central conductor, squeeze the insulation after the two filaments are twisted with concentricity, and then squeeze the semi-conductive layer and high-voltage insulation layer High-voltage insulation layer: general natural styrene-butadiene rubber DC maximum field force 27KV/mm, ethylene propylene insulation to take 35KV/mm; 4, external shielding layer: using 0.15-0.20mm tinned copper wire braiding, braid density is not less than 65%; or the use of metal belt wrapping; 5, sheath, the use of extra soft PVC or nitrile PVC extrusion.

19. Classification and characteristics of optical cables

Cable core construction	Structural characteristics
Layer stranded	The loosening structure of several secondary covered optical fibers around the central anti-tensioning part is a tube multi-fiber technology, and the optical cable can be as high as 144 cores, and the multi-fiber belt can be up to thousands of cores after replacing the fiber bundle.
Skeleton type	In the anti-tensile element outside the extruded plastic skeleton, the optical fiber is embedded in the skeleton slot, each slot can put one or more optical fibers or optical fiber strips, the slotted fiber should have a suitable remaining length, the structure of the ribbon optical cable optical fiber up to thousands of cores.
Central tubular	Fill a PBT tube with gel paste and put in 8 groups (12 fibers in each group) for a total of 96 fibers, with up to 216 fibers with fiber strips.
Unit type fiber optic cable	First a number of optical fibers in layers or skeleton type to make optical fiber units, and then the units twisted together, the current optical cable is developing in the direction of dense large fibers, the future is expected to reach 4000 cores.

20. Optical cables are divided according to the use environment

Usage environment	Use features
Buried straight	Buried directly underground, there are waterproof layers and armor layers for long-distance communication.
Pipe	Inside the laying pipe or tunnel, there is an aluminum belt PE composite layer for local calls or long-distance interruptions.
Overhead	Additional lightweight metal armor layer for use in provincial trunk or regional communication lines.
Inside the room	Flame retardant characteristics (low smoke and no halogen) should be used in the local area network in the building or as an indoor inlet for outdoor optical cable lines.
Inside the device	Lightweight single- or dual-core optical cable for in-device optical path connection.
Soft cables	Optical cables require softness, small size, light weight, good bendability and sufficient tensile resistance for non-fixed occasions and military mobile communications.
Underwater	Good radial and longitudinal sealing performance is required, and steel wire armor is required for communication line crossing areas.
The bottom of the sea	The cable core and anti-tensioning elements of the optical cable should be carefully designed, withstanding water pressure up to 80MPa, anti-tension of 80KN, DC resistance of 0.4Ω/km, the maximum supply voltage of 6KV, with a loose sleeve structure, loose pipe outside the winding two layers of steel wire.
Photoelectric integrated cable	The cable contains an 8-core optical fiber unit, 7 copper wire four-wire groups and 9 symmetrical line pairs, which are used in railway communication systems, optical fibers for trunk line large-capacity communication, and four-wire groups and line pairs for railway interval communication and signal transmission.
Fiber optic composite Power cables	Optical fibers are placed in the gap between three-phase cable cores to form a composite cable, which can transmit power and achieve data communication without induction and serial calls.
Fiber optic composite Overhead ground lines （OPGW）	The excellent characteristics of optical fiber and aluminum-clad steel wire are combined to form a high-performance cable, which can be used for both communication and ground; it can meet the demand for power production scheduling and power system automation for communication, and can also face the society, providing communication services for cable TV, public security systems, banking systems, post and telecommunications systems, for lines of 220KV and above, especially on new lines.
Full media Self-supporting optical cable （ADSS）	ADSS is used on 35-110KV lines, using the original power pole tower, near the power line to support its own erection along the pole, the center of the fiber optic cable with fiber reinforced plastic FRP as a reinforcing part, in the sheath put multi-strand aramid yarn as reinforcing material.

21. The type, form and use of cable core conductor material and metal shielding material

Metal type	Material form	Main use
copper and copper combine gold	pure copper	Copper cathode Copper wire ingots Copper round wire Copper wire Belt (foil)	Melted copper wire ingots, continuous casting and rolling copper rods, upper lead rods, dip rods Rolled copper rods and copper busbars Bare copper wire, wire and cable conductive wire core, metal shielded copper wire, enameled round copper wire core, electromagnetic (silk bag, paper bag) wire core Tram line (contact line) busbar Shielding of cables, outer conductors of coaxial cables, cord cores of telephone cords
copper combine gold	Round lines Hatches Strip	Conductive cores, electromagnetic wires, overhead wires for high-strength wires Tram wire (contact wire), oil-filled cable core Single-core cable armored reinforcement
aluminium and copper combine gold	pure aluminium	Aluminium ingots Aluminum wire ingots Round aluminium ingots Round lines Hatches With foil Pipe	Melted aluminum wire ingots, continuous casting and rolled aluminum rods Rolled aluminum rods and aluminum busbars Aluminum rod and profile line Overhead transmission lines, wire and cable conductive wire cores Electromagnetic wires, tram lines (contact lines), bus wires Cable shielding, comprehensive sheathing of communication cable (for shielding), external conductor of coaxial cable Conductor inside the communication cable
aluminium combine gold	Round lines Hatches Extra thin lines	Overhead transmission lines, wire and cable conductive wire cores Tram line (contact line) Electronics industry cables

22. Common terms and meanings of metal materials used in wire and cable

Name	Expressions and their meanings
Conductor resistivity ρ	ρ = (A / L) R equation: ρ is the conductor resistivity (Ω·mm2/m); A is the cross-sectional area of the specimen (mm2); L is the specimen length (m); R is the conductor resistance of the test (Ω).
Conductivity percent %1ACS	%1ACS=0.017241/ρ20。 The conductivity percentage value is expressed by the percentage of resistivity 0.017421Ω·mm2/m specified by the international annealed copper standard IACS, usually after the conductor resistivity ρ20 at known 20 °C, calculated according to the above formula. The conductivity of oxygen-free copper can reach 102.0%, and its resistivity ρ20= 0.017241/% IACS = 0.017241/0.02 = 0.0169Ω·mm2/m, which meets the requirements of copper wire resistivity ≤0.017421Ω·mm2/m for cable industry enterprises.
Resistance temperature coefficient a	Rt=RO[1+a(t—t0)]；ρt=ρ0[1+(a+γ)(t—t0)]。 Wherein: Rt, ρt are the resistance and resistivity at temperature t; RO and ρ0 are the resistance and resistivity at temperature t0; γ is the expansion coefficient of the material, when t is about 20 °C γ « a, negligible γ value; a value is related to the conductivity percentage value of the conductor %1ACS and the standard temperature selected, the a value of aluminum and aluminum alloys at 61% IACS and 20 °C is 0.00403; the a value of copper and copper alloys is 0.0393 when 00% IACS and 20 °C are active.
Melting point	The melting temperature at which a metal conductor changes from a solid state to a liquid state.
Coefficient of thermal expansion, Linear expansion coefficient	Metal conductors commonly used linear expansion coefficient γ (unit: °C-1), refers to the temperature t change 1 °C, the ratio of the increase or decrease of its length Lt to the length L0 at 0 °C: Lt = L0 (1 + γt)
Plastic stress σ	Under the action of external forces, the permanent deformation ability of a metal before breaking is called plastic stress (unit: N/mm2). In the tensile test, the ratio of tensile force P to the original cross-sectional area of the specimen A0 is a plastic stress: σ = P/A.
Yield point σs	The stress when the material is subjected to loads and strain increases and the stresses no longer increase with them are called yield points.
Tensile strength σb	During tensile testing, the stress corresponding to the maximum tensile force is called tensile strength (unit: N/ mm2). The ratio of the maximum tensile force Fb to the original cross-sectional area of the specimen A0 is the tensile strength: σb = Fb / A0
Elongation at break δ	In the tensile test, the percentage of the specimen's elongation after stretching is called the elongation at break and the original gauge L0: =[(L1-L0)/L0] ×100%. Wherein: L1 is the standard distance after the specimen is pulled off.
Fatigue limits	The maximum stress on which a metallic material is subjected to an infinite number of repetitive loads for a long time without breaking.
creep	Over time under the action of certain temperatures and stresses (within the elastic range), the metal produces irreparable deformation into creep. The higher the temperature, the greater the applied stress, and the faster the creep rate.
Brinell hardness HB	With a certain diameter of steel balls, pressed into the surface of the specimen with a specified load, after the specified load retention time, the load is removed, and the indentation spherical area of the specimen surface is determined, and the force per unit area is Brinell hardness. HB=2P/{πD[D—（D2—d2）1/2]}。 Wherein: P is the applied load; D is the diameter of the ball indenter; d is the indentation diameter.
Quenching heat treatment	Heated above the phase change temperature, then quenched to make the metal appear unstable tissue state, generally hardened after quenching.
Aging tempering treatment	The transformation of quenched metals from instability to a stable state, or the decomposition of quenched supersaturated solid melts, occurs at room temperature is called natural aging. The process carried out at artificial high temperatures is called artificial aging, and its effect is faster and the mechanical properties are significantly improved over time.
Annealing (toughening)	Cold work hardening occurs when the plastic deformation of the metal occurs, the hardness and strength increase, the plasticity decreases, and the plasticity is maintained at a certain temperature for a certain period of time in order to restore the plasticity, so that the metal transitions from an unstable state to a more stable state.

23. Common terms and meanings of the basic properties of plastics

Name	Meaning
Volume resistivity ρV	Leakage current is generated between the insulation thickness of wires and cables, and the corresponding resistance per unit volume (unit: Ω·m)
Surface resistivity ρS	The leakage current flowing through the insulation surface of the wire and cable, the resistance corresponding to the unit area (unit: Ω)
The dielectric constant ε	Engineering commonly used relative dielectric constant εt, Simple Music for the dielectric constant ε, the ratio of the capacitor C with a dielectric as a capacitor and the capacitor C0 with a vacuum as a capacitor is called the dielectric constant: ε = C / C0 (ε>1)
Dielectric loss and dielectric Loss angle tangent tanδ	The energy loss caused by the cable under the action of the alternating electric field Q is proportional to the applied voltage U, power supply frequency ω, cable capacitance C and dielectric loss angle tangent tanδ: Q = U2ω Ctanδ, at the time of U, ω, C, tanδ represents the dielectric loss.
Breakdown field strength Eb	When the cable insulation exceeds a certain value, the cable is broken down, and the ratio of voltage to the thickness of the insulation is called the breakdown field strength.
Electro-scarring and electro-scarring	The insulation surface is carbonized due to leakage current, a process called electromarking.
Electric tree discharge	The insulation of high-voltage cables causes dendritic cracking due to electron emission under local high-strength fields.
Water tree discharge	When the electric field and water exist at the same time as the high-voltage cable, there are pores, impurities, and semi-conductive layer spikes in the insulation, causing dendritic cracking in the insulation.
Corona discharge	In the local high field strength area of the cable, the local discharge phenomenon of the gas is generated, and the corona can lead to the cracking of the plastic, causing the electrical degradation to cause breakdown.
Vitrification temperature	The temperature at which the plastic changes from a highly elastic state to a glassy state.
Softening temperature	The temperature at which the plastic begins to soften when heated.
Melt Index MI	Also known as melt flow rate, the number of grams (unit: g/10min) of melt flowing out of a certain pore size every 10 minutes at a certain temperature and pressure.
Oxygen index OI	Just to maintain the minimum oxygen content in the mixture required for the combustion of combustible substances such as plastics, expressed in OI. The higher the OI value, the more difficult it is for combustible substances to burn.
Fuming	The tiny substances in the air of suspended solids, including vapor condensates, produced by decomposition during the combustion of polymers are smoke, and the ability of the material to produce smoke when burning is fumigogenic.
Degree of crosslinking	The degree to which the linear molecular structure of the polymer shifts to a spatial network of molecular structures.
Thermal extension	The degree of elongation and permanent deformation of plastic or rubber under heat and load is called thermal extension, which is used to assess the degree of crosslinking (vulcanization).
Heat deformation resistance	The deformation resistance of plastics under high temperature and pressure.
Low temperature embrittlement temperature	At low temperatures, when the plastic is subjected to a specific impact load, 50% of the specimens are broken at the temperature.
Heat aging resistance	The mechanical and electrical properties of plastics due to heat are called thermal aging, and their ability to resist thermal aging is called heat aging resistance. Heat aging resistance is measured by the retention of tensile strength and elongation before and after the aging test.
Weather resistance	Under atmospheric conditions, plastics are degraded by wind and rain, sun, ultraviolet light and atmospheric pollution, and their ability to resist deterioration is called weather resistance.
Resistant to environmental stress cracking	Crystalline plastics (such as polyethylene) due to the presence of internal stress in the processing and the use of environmental contact with chemical reagents, resulting in cracking, its ability to resist cracking is called environmental stress crack resistance.

24. Inspection of plastic cable material

Projects	Define or test methods
Density	The impregnation method and the density bottle (formerly known as the PYG) method are commonly used.
Absorbent	Expressed in percentage of water absorption (%).
Degree of crosslinking	The thermal extension method (stress-strain method) and equilibrium swelling method are commonly used in cross-linked cables to assess; the thermal extension method is to determine the elongation and permanent deformation of the specimen under thermal load. The swelling method is the weight ratio of placing small pieces of the specimen into xylene by 110 °C±2 °C and 24h before and after swelling.
Foamed plastic Apparent density	The weight of a unit volume of foam material at a specified temperature and relative humidity.
Tensile strength and Elongation at break	During tensile testing, the maximum tensile force of the specimen is subjected to fracture, and the ratio of the increase in the distance between the specimen and the initial distance when the specimen breaks.
Right angle tear strength	Right-angle tear strength equals tear load divided by specimen thickness.
Shore hardness	Using a Shore hardness tester, the depth of the pressure needle pressed into the specimen is converted to a hardness value.
Carbon black content	Determination of carbon black content and mineral fillers for cable insulation and sheathing.
Carbon black dispersion	The size of carbon black particles in the sample is observed with a microscope, and the degree of dispersion of carbon black in polyethylene is expressed by the evaluation method.
Thermoplastic Vika softening point	Determination of thermoplastics in liquid hot media. At a certain constant speed temperature rise under a certain load, the specimen is pressed into the temperature of 1 mm by a 1 mm2 pressure needle.
Melt flow rate	Also known as melt index MI, it means that the thermoplastic flows through the weight of the standard diameter of 10 min under a certain temperature and a certain load.
differential thermal analysis	For polyolefin insulation and sheathed materials for wires and cables, the thermal stability of the specimen is judged by determining the time when the automatic catalytic oxidation reaction of the specimen begins under high temperature oxygen conditions.
Thermally stable at 200°C Time	The thermal stability of the specimen is judged by determining the time when the decomposition reaction of the specimen begins at a high temperature of 200 °C.
Thermal deformation	For PVC plastic for wire and cable, the deformation of the specimen under a certain load is determined at 120 ° C, and the heat deformation is the ratio of the thickness removed by compression to the original thickness of the specimen.
PE is environmentally resistant Stress cracking	When the reagent of the specified concentration is injected into the glass tube of the sample, the first specimen cracking time is F0 time, which is the failure specimen, and the time when the number of failed specimens reaches 50% is F50 time.
Low temperature impact Embrittlement temperature	The specimen is in a certain hot medium (industrial alcohol), bent by the impact of the punch hammer 90 °, when the specimen is destroyed (the specimen must be divided into two segments) reaches a 50% probability of the temperature.
Resistant to chemicals (Drugs such as: ethanol, hydrochloric acid, nitric acid, sulfuric acid, etc.)	The specimen should be soaked in a liquid reagent, and after a specified time at 23 °C ± 2 °C, observe the changes in the weight, size and appearance of the sample, and record the measurement results before and after soaking.
Oil resistance	The soaking time and temperature of soaking oils such as mineral oil, turpentine, kerosene, gasoline, etc. should be carried out in accordance with the provisions of the product standard.
Oxygen index	The specimen is in a mixture of oxygen and nitrogen, maintaining just the minimum oxygen content required for combustion.
Flashing temperature and Spontaneous combustion temperature	The material is heated to liberate combustible gases, just can be lit by the external flame, then the initial temperature of the air is a flash point, the plastic is heated to a certain temperature, without the external fire source and spontaneous combustion, flameless combustion or explosion, then the initial temperature of the surrounding air is the spontaneous ignition point.
Hydrogen chloride content	Quantitative determination of the gas released when the wire and cable material is burned, mainly for water-soluble gases, such as HCL, etc., with a special hydrogen halide content for determination.
Smoke density	There are two kinds of fumeability tests when the wire and cable materials are burned, namely, weight measurement method and photometric method. The former is to determine the weight loss value before and after the combustion of the material, thereby inferring the amount of smoke; the latter is to determine the amount of smoke by measuring the amount of decay of the time intensity of the generated smoke, also known as the specific optical density measurement method (NBS method).
Resistivity	The volume resistivity ρV and surface resistivity ρS of the insulating material are determined by the high impedance meter method and determined separately by a three-electrode system.
Power frequency electrical strength	Electrical strength is the ratio of the voltage to the thickness of the specimen when it fails under specified conditions.
The dielectric constant ε and dielectric loss angle tangent tanδ	The ε and tanδ are measured with a three-electrode system and an AC bridge, the former calculated by a formula and the latter read directly by a measuring instrument.
Aging performance measurement	Using the airbox thermal aging method, the test results are expressed as the rate of change in tensile strength and the rate of change in elongation at break before and after aging.

25. Proper performance nouns of rubber and rubber and their meanings

Name	Meaning
Mooney viscosity	The shear resistance of unsulfurized compounds at a certain temperature pressure and time is expressed in terms of Mooney viscosity.
Vulcanization	Under certain conditions, the mixed rubber compound makes the rubber molecules change from linear structure to network spatial structure.
Positive vulcanization point	When vulcanizing, the temperature and time selected so that the properties (mechanics) of the vulcanized adhesive reach or approach the optimal point, respectively.
Scorched	Rubber undergoes local pre-vulcanization during the refining and mixing process, causing it to harden or crack.
Wyeth plasticity	The rubber material is deformed by external forces, and its deformation performance can still be maintained after the external force is eliminated, that is, plasticity. The plasticity measured with a Wyehrs plasticity meter is called Wyeth plasticity.
Constant elongation strength	The force on the specimen per unit area when it is stretched to a specified elongation rate.
Ozone resistance	Ozone accelerates the aging of the eraser and resists the action of a certain concentration of ozone under certain conditions (temperature, time).

26. Types and uses of armor protection materials

class	Materials	Usage
Armor material	Lead, lead alloys	Waterproof and shockproof metal outer sheaths for power cables and communication cables.
Steel wire steel belt	It is used for power cable overhead structure and reinforcement parts, steel wire braid, steel wire layer of cable armor, reinforcing core for optical cable, self-supporting optical cable cable, steel belt armored layer that withstands mechanical pressure.
Protective coatings	Asphalt coatings	Used in various cable metal sheaths.
Rubber-based coatings	Aluminum strand for anti-corrosion steel core.
Nitrocellulose paint	For coated with rak wire fiber braid.
Bio-preservatives	Used for anti-rat, anti-ant, anti-mildew coating layer for wires.
Strip	Pressure-sensitive adhesive tape	Used for cable joint terminal insulation, fire seal.
Self-adhesive rubber tape	For medium and low voltage cable glands.
Metal plastic composite tape	For bonding sheaths and armor.
Fire protection pack belt	Used for flame retardant, fireproof insulation layer, protective layer.

Retweeting is the biggest encouragement! Thank you for your support!

Tips

Electrician exclusive information: including from the introductory to advanced electrician learning materials, 167 electrician e-books, classic electrical PPT, the real questions of the electrician examination over the years, the electrician's necessary practical training simulation software, the electrical automation industry types of technical manuals!