Medium Voltage Cables

Medium Voltage Cables to BS 6622

Medium Voltage Cables to IEC 60502

Medium Voltage Cables to VDE 0276

Medium Voltage Cables to IEC 60502

Single Core Cables to IEC 60502

Application
The single core cables are designed for distribution of electrical power with nominal voltage Uo/U ranging from 1.8/3KV to 26/35KV 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
IEC 60502 Part 1(1.8/3KV)
IEC 60502 Part 2(3.6/6KV to 18/30KV

Construction

Conductor: Plain annealed copper or aluminium complying with IEC 60228 class 1 or 2.
Conductor Screen: The conductor screen consists of an extruded layer of non metallic, semi-conducting compound firmly bonded to the insulation to exclude all air voids. The conductor screen is not necessary for both PVC and EPR/HEPR insulated 1.8/3KV and 3.6/6KV cables.
Insulation: Insulation is of polyvinyl chloride (PVC) intended for 1.8/3KV and 3.6/6KV cables, cross-linked polyethylene compound (XLPE) or ethylene propylene rubber (EPR/HEPR).
Table 1. Insulation Thickness Of XLPE Or EPR/HEPR Insulation

Nom. Cross Section Area	Insulation Thickness at Nominal Voltage
	1.8/3KV (Um=3.6KV)	3.6/6KV (Um=7.2KV)			6/10KV (Um=12KV)	8.7/15KV (Um=17.5KV)	12/20KV (Um=24KV)	18/30KV (Um=36KV)	21/35KV (Um=42KV)	26/35KV (Um=42KV)
mm2	mm	mm			mm	mm	mm	mm	mm	mm
	XLPE/EPR	XLPE	EPR		XLPE/EPR	XLPE/EPR	XLPE/EPR	XLPE/EPR	XLPE/EPR	XLPE/EPR
			Unscreened	Screened
10	2.0	2.5	3.0	2.5	-	-	-	-	-	-
16	2.0	2.5	3.0	2.5	3.4	-	-	-	-	-
25	2.0	2.5	3.0	2.5	3.4	4.5	-	-	-	-
35	2.0	2.5	3.0	2.5	3.4	4.5	5.5	-	-	-
50 – 185	2.0	2.5	3.0	2.5	3.4	4.5	5.5	8.0	9.3	10.5
240	2.0	2.6	3.0	2.6	3.4	4.5	5.5	8.0	9.3	10.5
300	2.0	2.8	3.0	2.8	3.4	4.5	5.5	8.0	9.3	10.5
400	2.0	3.0	3.0	3.0	3.4	4.5	5.5	8.0	9.3	10.5
500 - 1600	2.2-2.8	3.2	3.2	3.2	3.4	4.5	5.5	8.0	9.3	10.5

*Insulation Thickness of PVC is 3.4mm (1- 1600mm sq) for 3.6/6KV cables.

Insulaton Screen: The insulation screen consists of an extruded layer of non metallic, semi- conducting compound extruded 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. The insulation screen is not necessary for both PVC and EPR/HEPR insulated 1.8/3KV and 3.6/6KV cables. The screen may be covered by semi-conductive water blocking swellable tape to ensure longitudinal watertightness.
Metallic Layer: The metallic layer may be applied over the individual cores or the core assembly collectively.
The following types of metallic layers are provided:
1) Metallic Screen
2) Concentric Conductor
3) Metallic Sheath
4) Metallic armour
The metallic screen shall consist of either copper tapes or a concentric layer of copper wires or a combination of tapes and wires to provide an earth fault current path. The concentric conductor is applied directly either over the insulation, or over the insulation screen or over an inner covering. The metallic sheath consists of lead or lead alloy applied as a tightly fitting seamless tube. The metallic armour consists of either flat wire armour, round wire armour, and double tape armour.

Table 2. Minimum Total Cross Section Of Metallic Screen

Nom. Cross-Section Area of Cable	Min. Cross-Section of Metallic Screen	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
800-1000	50	0.35

Separation Sheath (for armoured cable): The separation sheath comprises a layer of extruded PVC, PE or LSZH, applied under the armour .The nominal thickness is calculated by 0.02Du + 0.6mm where Du is the fictitious diameter under the sheath in mm. For cables without a lead sheath, the nominal separation sheath thickness shall not be less than 1.2mm. For cables where the separation sheath is applied over the lead sheath, the nominal separation sheath thickness shall not be less than 1.0mm.
Lapped Bedding (for armoured lead sheathed cable): The lapped bedding consists of either impregnated/synthetic compounded paper tapes or a combination of two layers of these paper tapes followed by a few layers of compounded fabulous materials. The thickness is around 1.5mm.
Armour (for armoured cable): The armour consists of round aluminium wire armour applied helically over an extruded separation sheath.
Table 3. Round Armour Wire Diameter

Fictitious Diameter Under the Armour		Armour Wire Diameter
mm		mm
>	<
-	10	0.8
10	15	1.25
15	25	1.6
25	35	2.0
35	60	2.5
60	-	3.15

Over Sheath: Overall sheath comprises a layer of extruded thermoplastic compound (PVC, PE or LSZH can be offered as an option.) or elastomeric compound (polychlorprene CSP or chlorosulfonated PE). The nominal oversheath thickness is calculated by 0.035D+1 where D is the fictitiuous diameter immediately under the oversheath in mm. For unarmoured cables and cables with the oversheath not applied over the armour, metallic screen or concentric conductor, the nominal oversheath thickness shall not be less than 1.4mm. And for cables with oversheath applied over the armour, metallic screen or concentric conductor, the nominal oversheath thickness shall not be less than 1.8mm.

PHYSICAL PROPERTIES:

Operating Temperature: up to 70°C (PVC insulation); up to 90°C (XLPE or EPR insulation)
Temperature Range: -5°C ( PVC sheath ); -20°C ( PE sheath )
Short Circuit Temperature( 5 seconds maximum duration ): 140-160°C (PVC insulation);
250°C (XLPE or EPR insulation)
Bending Radius: 12 x OD

Table 4. Nominal /Operating /Testing Voltages

Rated Voltage Uo/U	Operating Voltage (Um)	Testing Voltage (rms)
1.8/3KV	3.6KV	6.5KV
3.6/6KV	7.2KV	12.5KV
6/10KV	12KV	21KV
8.7/15KV	17.5KV	30.5KV
12/20KV	24KV	42KV
18/30KV	36KV	63KV
21/35KV	42KV	73.5(53)*KV
26/35KV	42KV	91(65)*KV

*21/35KV and 26/35kV power frequency voltage test can be made under the following conditions: 2.5Uo x 30mins or 3.0Uo x 15mins. Numbers in brackets refer to the test values for 3.0Uo x 1.5mins.

Single Core 1.8/3KV (Um=3.6KV) Dimensional Data

Nom. Cross- Section Area				Unarmoured Cables				Steel Wire Armoured Cables
	Nom. Insulation Thickness	Copper Tape Thickness	Copper Wire Screen Area*	Nom. Sheath Thickness	Approx. Overall Diameter	Approx. Weight		Nom. Bedding Thickness	Armour Wire Size	Nom. Sheath Thickness	Approx. Overall Diameter	Approx. Weight
						CU	AL					CU	AL
mm2	mm	mm	mm2	mm	mm	kg/km		mm	mm	mm	mm	kg/km
10	2.0	0.1	16	1.8	13	240	180	1.2	1.6	1.8	18	460	400
16	2.0	0.1	16	1.8	13	300	200	1.2	1.6	1.8	19	530	430
25	2.0	0.1	16	1.8	15	410	250	1.2	1.6	1.8	20	650	500
35	2.0	0.1	16	1.8	16	510	300	1.2	1.6	1.8	21	780	560
50	2.0	0.1	16	1.8	17	640	350	1.2	1.6	1.8	22	930	640
70	2.0	0.1	16	1.8	19	850	440	1.2	1.6	1.8	24	1170	750
95	2.0	0.1	16	1.8	20	1130	540	1.2	1.6	1.8	26	1460	870
120	2.0	0.1	16	1.8	22	1370	630	1.2	1.6	1.8	27	1730	990
150	2.0	0.1	25	1.8	23	1650	730	1.2	1.6	1.8	29	2030	1110
185	2.0	0.1	25	1.8	25	2010	860	1.2	1.6	1.9	30	2430	1280
240	2.0	0.1	25	1.8	27	2570	1050	1.2	1.6	2.0	33	3040	1530
300	2.0	0.1	25	1.8	29	3160	1250	1.2	2.0	2.1	36	3760	1860
400	2.0	0.1	35	1.9	33	3980	1560	1.2	2.0	2.2	39	4660	2230
500	2.2	0.1	35	2.1	35.5	4910	1905	1.3	2.5	2.5	43	5930	2930
630	2.4	0.1	35	2.2	39.7	6340	2420	1.4	2.5	2.6	49	7370	3430
800	2.6	0.1	50	2.3	44.5	7890	2980	1.4	2.5	2.7	52	9070	4230
1000	2.8	0.1	50	2.5	49.4	9890	3700	1.5	2.5	2.9	56	11100	4950

*Optional wire screen can be provided in combination of copper tapes. Nominal screen area, as stated in the table, can be supplied as standard.

Electrical Data

Nom. Cross- Section Area	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 1 sec	Short Circuit Rating of Copper Tape Screen 1 sec	Reactance		Inductance		Impedance
								Trefoil	Flat Spaced	Trefoil	Flat Spaced	Trefoil		Flat Spaced
												cu	AL	cu	AL
mm2	µΩ/m	µΩm	kA	pF/m	mA/m	kA	kA	µΩ/m		nH/m		µΩ/ m		µΩ/ m
10	1830/3080	2330/3920	1.4/0.9	182	0.27	2.6	0.2	151	201	384	558	2332	3846	2332	3840
16	1150/1910	1460/2420	2.2/1.4	201	0.29	2.6	0.3	140	193	362	546	1462	2411	1478	2420
25	727/1200	927/1538	3.6/2.3	222	0.32	2.6	0.3	131	185	345	535	936	1544	952	1554
35	524/868	668/1113	5.0/3.2	251	0.35	2.6	0.4	122	178	327	524	679	1121	695	1131
50	387/641	494/822	6.8/4.4	281	0.39	2.6	0.4	116	172	313	514	511	834	527	844
70	268/443	343/568	9.8/6.3	341	0.45	2.6	0.5	110	165	300	495	364	583	386	597
95	193/320	248/410	13.3/8.5	397	0.50	2.6	0.5	104	160	287	485	272	427	300	446
120	153/253	196/325	17.2/11.0	430	0.55	2.6	0.6	104	159	283	480	225	345	257	367
150	124/206	159/266	21.2/13.5	464	0.59	4.3	0.6	100	156	280	475	193	287	229	313
185	99.1/164	128/211	26.6/17.0	513	0.65	4.3	0.7	98	154	274	465	165	237	206	267
240	75.4/125	98/161	34.9/22.3	573	0.70	4.3	0.9	94	150	267	459	140	191	185	226
300	60.1/100	80/130	43.8/28.0	652	0.72	4.3	1.0	91	147	260	455	128	163	174	203
400	47.0/77.8	64/102	57.3/36.6	727	0.75	5.8	1.1	90	147	253	445	113	141	164	184
500	36.6/60.5	51/81	72.3/46.2	754	0.79	5.8	1.2	89	145	248	435	105	124	158	171
630	28.3/46.9	42/64	91.2/58.3	786	0.87	5.8	1.3	86	143	245	425	97	110	151	160
800	22.1/36.7	35/55	114.4/75.0	846	0.91	8.2	1.4	85	142	243	415	92	101	147	153
1000	17.6/29.1	30/46	143.0/94.0	916	0.99	8.2	1.5	83	141	239	405	88	95	144	148

Single Core 3.6/6KV (Um=7.2KV)
Single Core 6/10KV (Um=12KV)
Single Core 8.7/15KV (Um=17.5KV)
Single Core 12/20KV (Um=24KV)  
Single Core 18/30KV (Um=36KV)
Single Core 21/35KV (Um=42KV)
Single Core 26/35KV (Um=42KV)
Current Rating for Single Core 1.8/3KV(Um=3.6KV ) to 26/35KV(Um=42KV)

Current Rating Conditions:

Ground Temperature: 20°C
Ambient Temperature (air): 30°C
Depth of Soil: 0.8m
Thermal Resistance of Soil: 1.5K•m/W