Table A

Nominal area of conductor mm2	Two Core		Three and Four Core
	Current rating amp	Volt drop per amp per meter mV	Current rating amp	Volt drop per amp per meter mV
1.5	29	31	25	27
2.5	39	19	33	16
4	52	12	44	10
6	66	7.9	56	6.8
10	90	4.7	78	4.0

Rating based on Ambinent air temp 30° c
Laid directly in ground, run single - way ducts

Table B

Nominal area of conductor mm2	Two Core			Three and Four Core
	Current rating		Volt drop per amp per meter mV	Current rating		Volt drop per amp per meter mV
	In Ground amp	In Duct amp		In Ground amp	In Duct amp
1.5	25	25	31	25	25	27
2.5	33	33	19	33	33	16
4	44	44	12	44	44	10
6	56	56	7.9	56	56	6.8
10	78	78	4.7	78	78	4.0

Table C

Nominal area of conductor mm2	Two Core		Three and Four Core
	Current rating amp	Volt drop per amp per meter mV	Current rating amp	Volt drop per amp per meter mV
1.5	22	29	19	25
2.5	31	18	26	15
4	41	11	35	9.5
6	53	7.3	45	6.4
10	72	4.4	62	3.8

Rating based on Ambinent air temp 30° c
Laid directly in ground, run single - way ducts

Table D

Nominal area of conductor mm2	Two Core			Three and Four Core
	Current rating		Volt drop per amp per meter mV	Current rating		Volt drop per amp per meter mV
	In Ground amp	In Duct amp		In Ground amp	In Duct amp
1.5	32	26	29	27	22	25
2.5	41	34	18	35	29	15
4	55	45	11	47	38	9.5
6	69	57	7.3	59	48	6.4
10	92	76	4.4	78	64	3.8

Table E

Ambient air temperature	25°c 30°c 35°c 40°c 45°c 50°c 55°c
Cable Type	Rating Factor
XLPE and LSF cable	1.41, 1.10, 1.05, 1.00, 0.95, 0.89, 0.84
PVC Cable	1.22, 1.15, 1.08, 1.00, 0.91, 0.82, 0.71

Correction fator for Group of Cables, insulated in air

Table F

Arrangement of cables	2, 3, 4, 5, 6, 7, 8, 9, 10
In conduict, trunking or bunched and clipped directly	0.8, 0.7, 0.65, 0.6, 0.57, 0.54, 0.52,0.5, 0.58
On metal tray and Cable touching	0.86, 0.81, 0.77, 0.75, 0.74, 0.73, 0.73, 0.72, 0.71

Ratin factor for depth of laying
(to center of cable or to center of duct)

Table G

Depth of Laying m	Multi Core Cables
	Direct in Ground	In single way cables
0.50	1.00	1.00
0.60	0.99	0.99
0.80	0.97	0.97
1.00	0.95	0.96
1.25	0.94	0.95

 

Table H

Type of Installation	Soil thermal resistivity in "Cm/W
	0.8, 0.9, 1.0, 1.5, 2.0, 2.5
Multi Core Cables laid directly in Ground	1.09, 1.06, 1.04, 0.93, 0.84, 0.77
Multi Core Cables installed in single way ducts	1.03, 1.02, 1.02, 0.97, 0.91, 0.87

Rating factors for ground temperature
(Cables laid direct or in ducts)

Table I

Ground temperature	15°c 20°c 25°c 30°c 35°c 40°c 45°c
XLPE Insulated	1.12, 1.08, 1.04, 1.00, 0.96, 0.91, 0.87
PVC Insulated	1.07, 1.12, 1.06, 1.00, 0.94, 0.87, 0.79

Group Rating factors for multi core cables in horizontal formation (average values)

Table J

	Number of cables in group	Spacing between cable centres
		Touching	0.15m	0.3m	0.45m	0.6m
Cable direct in ground	2	0.81	0.87	0.91	0.93	0.94
	3	0.70	0.78	0.84	0.87	0.90
	4	0.63	0.74	0.81	0.86	0.89
	5	0.59	0.70	0.78	0.83	0.87
	6	0.55	0.67	0.76	0.82	0.86
Cable in single way ducts	2	0.90		0.93	0.95	0.96
	3	0.82		0.87	0.90	0.93
	4	0.78		0.85	0.89	0.91
	5	0.76		0.82	0.87	0.90
	6	0.72		0.81	0.86	0.90