Rating Factors for Variation in Thermal Resistivity of Soil for Two Single-Core Cables in Ducts:

Nominal Area of Conductor mm²	Thermal Resistivity of Soil in K.m/W
	0.7	0.8	0.9	1.0	1.2	1.5	2.0	2.5	3.0	3.5	4.0
50	1.08	1.06	1.04	1.03	1.00	0.96	0.90	0.85	0.81	0.77	0.74
70	1.08	1.06	1.05	1.03	1.00	0.96	0.90	0.84	0.80	0.76	0.73
95	1.08	1.07	1.05	1.03	1.00	0.95	0.89	0.84	0.80	0.75	0.72
120	1.09	1.07	1.05	1.03	1.00	0.95	0.89	0.83	0.79	0.75	0.71
150	1.09	1.07	1.05	1.03	1.00	0.95	0.88	0.83	0.79	0.74	0.71
185	1.09	1.07	1.05	1.03	1.00	0.95	0.88	0.83	0.78	0.74	0.70
240	1.10	1.08	1.05	1.04	1.00	0.95	0.88	0.82	0.78	0.73	0.70
300	1.10	1.08	1.06	1.04	1.00	0.95	0.87	0.82	0.77	0.72	0.69
400	1.11	1.08	1.06	1.04	1.00	0.94	0.87	0.82	0.77	0.72	0.68
500	1.12	1.08	1.06	1.04	1.00	0.94	0.87	0.81	0.76	0.71	0.68
630	1.12	1.09	1.06	1.04	1.00	0.94	0.87	0.81	0.76	0.71	0.67
800	1.13	1.10	1.07	1.04	1.00	0.94	0.86	0.80	0.75	0.71	0.67
1000	1.13	1.10	1.07	1.04	1.00	0.94	0.86	0.80	0.75	0.70	0.66