Tianjin Feiya Wire&Cable Co.,Ltd

Product Detail
Medium Voltage Cables to BS 6622  Three Core Cables to BS 6622
Detail

Application
The three core cables are designed for distribution of electrical power with nominal voltage Uo/U ranging from 3.6/6.6KV to 19/33KV and frequency 50Hz. They are suitable for installation mostly in power supply stations, indoors and in cable ducts, outdoors, underground and in water as well as for installation on cable trays for industries, switchboards and power stations.

Standards
BS 6622

Construction

Conductor: Plain annealed copper or aluminium complying with IEC 60228/BS 6360. Copper conductors shall be stranded (class 2) and aluminium conductors shall be either solid or stranded (class 2).
Conductor Screen: Extruded layer of semi-conducting cross-linkable compound is applied over the conductor and shall cover the surface completely. The minimum thickness is 0.3mm and the maximum resistivity shall not exceed 500 Ohm-m at 90°C.
Insulation: Insulation is of cross-linked polyethylene compound XLPE (GP8) conforming to
BS 7655-1.3 or EPR (GP7), conforming to BS 7655-1.2.

Table 1. Insulation Thickness

Nom. Cross
Section Area

Insulation Thickness at Nom. Voltage

3.8/6.6KV(Um=7.2KV)

6.35/11KV(Um=12KV)

8.7/15KV(Um=17.5KV)

12.7/22KV(Um=24KV)

19/33KV(Um=36KV)

mm²

mm

mm

mm

mm

mm

70 – 185

2.5

3.4

4.5

5.5

8.0

240

2.6

3.4

4.5

5.5

8.0

300

2.8

3.4

4.5

5.5

8.0

400

3.0

3.4

4.5

5.5

8.0

Above 500

3.2

3.4

4.5

5.5

8.0

Insulaton Screen: Extruded layer of semi-conducting cross-linkable compound is applied over the insulation. The extruded semi-conducting layer shall consist of bonded or cold strippable semi-conducting compound capable of removal for jointing or terminating. As an option, a semi -conducting tape may be applied over the extruded semi-conducting layer as a bedding for the metallic layer. The minimum thickness is 0.3 mm and the maximum resistivity is 500 Ohm-m at 90°C. The screen is tightly fitted to the insulation to exclude all air voids and can be easily hand stripped on site.
Inner Covering & Fillers: For cables with a collective metallic layer or cables with a metallic layer over each individual cores with additional collective metallic layers, semi-conducting inner covering and fillers shall be applied over the laid up cores. The inner covering is made of non hygroscopic material, except if the cable is to be made longitudinally watertight. The inner covering shall be extruded or lapped.
The approximate thickness of extruded inner coverings is given in Table 2:

Table 2. Approximate Thickness Of Extruded Inner Coverings

Ficititous Diameter Over Laid Up Cores

Approx. Thickress of Extruded Inner Covering

mm

mm

>

<


35

45

1.0

25

35

1.2

35

45

1.4

45

60

1.6

60

80

1.8

80

-

2.0

*The approximate thickness of lapped inner coverings shall be 0.6mm.

Metallic Layer: The metallic layer shall be applied over each core or applied as a collective screen. The metallic screen shall consist of either copper tapes or a concentric layer of copper wires or a combination of tapes and wires. The metallic layer provides an earth fault current path, capable of withstanding fault current to earth of 1000A for one second at maximum temperature 160°C. Copper wires are applied over the conducting water blocking layer with a minimum diameter of 0.5mm. And over the copper wires, copper tape with minimum thickness of 0.1mm can be applied helically with overlap.
Total cross section of copper wire screen is shown in table 3.

Table 3. Minimum Total Cross Section Of Copper Wire Screen & DC Resistance Of The Screen

Nominal Cross-Section
Area of Cable

Minimum Cross-Section
of Copper Wire Screen Area


DC Resistance of the Copper Wire Screen

mm²

mm²

mm

up to 120

16

1.06

150-300

25

0.72

400-630

35

0.51

Separation Sheath (for armoured cable): The separation sheath comprises a layer of extruded PVC, PE or LSZH. The nominal thickness is calculated by 0.02Du + 0.6mm where

Du is the fictitious diameter under the sheath in mm. The nominal separation sheath thickness shall not be less than 1.2mm.
Armour (for armoured cable): The armour consists of galvanized steel wire applied over the inner covering with diameter specified as in Table 4.

Table 4. Armour Wire Diameter

Fictitiious Diameter Under the Armour

Armour Wire Diameter

mm

mm

>

<



25

1.6

25

35

2.0

35

60

2.5

60

-

3.15

Over Sheath: Overall sheath comprises a layer of extruded either PVC type 9 conforming to BS 7665-4.2 or MDPE type TS2 conforming to BS 7655-10.1; LSZH can be offered as an option. The oversheath is normally black in colour. When a DC voltage test is to be performed on the oversheath, a semi-conducting layer such as graphite coating shall be applied over the surface of the extruded oversheath. The nominal oversheath thickness is calculated by 0.035+D where D is the diameter immediately under the oversheath in mm. For cables with the oversheath not applied over the armour, the nominal oversheath thickness shall not be less than 1.4mm. And for cables with oversheath applied over the armour, the nominal oversheath thickness shall not be less than 1.8mm.

PHYSICAL PROPERTIES:

Operating Temperature: up to 90°C
Temperature Range: -5°C ( PVC sheath ); -20°C ( PE sheath )
Short Circuit Temperature: 250°C (short circuit duration up to 5 seconds)
Bending Radius: 15 x OD

Table 5. Nominal /Operating /Test Voltages

Rated Voltage Uo/U

Operating Voltage (Um)

Testing Voltage (rms)

3.8/6.6KV

7.2KV

15KV

6.35/11KV

12KV

25.5KV

8.7/15KV

17.5KV

35KV

12.7/22KV

24KV

51KV

19/33KV

36KV

76KV

Three Core 3.8/6.6KV (Um=7.2KV) Dimensional Data

Nom.
Cross-
Section
Area


Unarmoured Cables

Steel Wire Armoured Cables

Nom.Insulation Thickness

Copper Tape Screen Area

Nom.Sheath
Thickness

Approx. Overall Diameter

Approx. Weight

Copper Tape Screen Area

Nom.Bedding
Thickness

Nom. Armour Wire Diameter

Nom.Sheath Thickness

Approx. Overall Diameter

Approx.
Weight

CU

AL

CU

AL

mm2

mm

mm2

mm

mm

kg/km

mm2

mm

mm

mm

mm

kg / km

25

2.5

16

2.1

37.7

2205

1740

3.4

1.2

2.0

2.2

44.5

3890

3465

35

2.5

16

2.3

41.2

2690

2010

3.6

1.2

2.5

2.3

46.8

4420

3730

50

2.5

16

2.5

44.9

3340

2350

3.8

1.3

2.5

2.5

51.5

5640

4690

70

2.5

16

2.6

48.0

4050

2730

4.3

1.3

2.5

2.6

55.0

6570

5240

95

2.5

16

2.7

51.7

5000

3180

4.7

1.4

2.5

2.7

58.9

7760

5890

120

2.5

16

2.8

54.7

5890

3590

5.0

1.5

2.5

2.8

62.1

8810

6510

150

2.5

25

2.9

58.4

6960

4160

5.3

1.5

2.5

2.9

65.8

10110

7310

185

2.5

25

3.0

61.9

8160

4650

5.8

1.6

2.5

3.0

69.5

11520

7960

240

2.6

25

3.2

68.1

10210

5530

6.3

1.7

2.5

3.2

75.9

13920

9140

300

2.8

25

3.5

73.6

12380

6670

7.0

1.8

3.15

3.5

83.1

17400

11620

400

3.0

35

3.7

83.8

16190

8430

7.7

2.0

3.15

3.7

93.0

21900

13980

Electrical Data

Nom.
Cross-
Section
Area


Unarmoured Cables

Steel Wire Armoured
Cables


Current Ratings

D C Resistance
CU / AL

A C Resistance
CU / AL

Short Circuit Rating of
Conductor
CU / AL
1 sec

Capaci-
tance

Charging Current

Short Circuit Rating of Copper Wire Screen
Per Core
1 sec

Short Circuit Rating of Copper Tape Screen Per Core
1 sec

Reac-tance

Induc-
tance

Ground

Duct

Air

CU

AL

CU

AL

CU

AL

mm2

µΩ/m

µΩ/m

kA

pF/m

mA/m

kA

kA

µΩ/m

nH/m

A

A

A

25

727/1200

927/1538

3.6/2.3

272

0.33

2.6

0.4

113

370

140

115

125

95

145

115

35

524/868

668/1113

5.0/3.2

301

0.36

2.6

0.5

108

350

170

135

150

115

175

140

50

387/641

494/822

6.8/4.4

332

0.40

2.6

0.5

102

330

210

160

180

135

220

170

70

268/443

343/568

9.8/6.3

383

0.46

2.6

0.6

97

310

255

195

215

165

270

210

95

193/320

248/410

13.3/8.5

432

0.52

2.6

0.6

92

290

300

230

255

200

330

250

120

153/253

196/325

17.2/11.0

474

0.57

2.6

0.7

89

280

340

265

290

225

375

295

150

124/206

159/265

21.2/13.5

511

0.61

4.3

0.7

87

280

380

295

330

255

430

330

185

99.1/164

128/211

26.6/17.0

562

0.67

4.3

0.8

86

270

430

335

370

290

490

385

240

75.4/125

98/161

34.9/22.3

602

0.72

4.3

0.9

83

260

490

380

425

335

570

450

300

60.1/100

80/130

43.8/28.0

622

0.75

4.3

1.0

82

260

540

435

470

375

650

510

400

47.0/77.8

64/102

57.3/36.6

648

0.78

5.8

1.1

80

250

590

480

520

420

700

570



CONTACT US Tel: 0086-22-83965099
Mobile: 0086 15510897703
CONTACT EMAIL amy@cn-fengda.com
Login
Login
Login by:
leave a message
back to the top