شركة الخليج للكابلات والصناعات الكهربائية

Rating factors for Air, Ground and Duct

RATING FACTORS FOR VARIATION IN
AMPIENT TEMPERATURE FOR CABLES LAID IN AIR

Ambient temperature °C	25	30	35	40	45	50	52	55	60
XLPE insulated cables	1.37	1.30	1.24	1.17	1.09	1.03	1.00	0.95	0.88

RATING FACTORS FOR VARIATION IN GROUND TEMPERATURE
FOR CABLES LAID DIRECT IN GROUND OR IN DUCTS

Ground Temperature °C	15	20	25	30	35	40	45
XLPE insulated cables	1.16	1.13	1.08	1.03	1.00	0.95	0.90

RATING FACTORS FOR DEPTHS OF LAYING FOR
CABLES LAID DIRECT IN GROUND OR IN DUCTS

Depth of Laying Metre	600/1000 V Cables 1.9/3.3 KV to 19/33 KV Cables
	Cables Laid in Ground			Cables Laid in Ducts	Cables Laid in Ground
	upto 50 Sqmm	70 Sqmm to 300 Sqmm	Above 300 Sqmm	Multicore	Upto 300 Sqmm	Above 300 Sqmm
0.50	1.026	1.036	1.055	1.026	-	-
0.60	1.015	1.016	1.023	1.015	-	-
0.75	1.000	1.000	1.000	1.000	-	-

0.80	0.995	0.995	0.992	0.995	1.020	1.031
1.00	0.974	0.975	0.970	0.985	1.000	1.000
1.25	0.964	0.953	0.949	0.974	0.980	0.979

1.50	0.954	0.943	0.939	0.964	0.969	0.969
1.75	0.944	0.922	0.918	0.964	0.959	0.948
2.00	0.933	0.912	0.907	0.954	0.939	0.928

2.50	0.923	0.902	0.897	0.954	0.929	0.918
3.00	0.913	0.891	0.876	0.944	0.918	0.907
or more

Depth of laying is measured from surface of ground to the centre of a Cable/Duct or to the centre of a trefoil group of Cables/ducts as the case may be.

Lead Sheathed Cables/Current Ratings/Rating factors for Air, Ground and Duct

Rating factors for Air, Ground and Duct