For installation condition other than the standard ones rating factors have to be applied as given in tables.

Arrangement for which reduction in current rating is not required:

For cables sizes upto 70 sq. mm. conductor section, reduction in rating for grouping for cable in air need not be applied, provided, the circuits are run with a clearance of at least 75 mm and installed in a horizontal plane, when number of circuits are more than three. For cables above 70 sq. mm. conductor section, no reduction in rating be applied provided the circuits are run with a clearance of at least 150 mm, and installed in a horizontal plane as and when the number of circuits exceed four.

Short time and intermittent Rating

As in the case of any other electrical equipment, electric cables also, although, designed to carry a continuous load with a specified temperature rise under defined ambient conditions; are capable of carrying loads in excess of such continuous ratings for short duration without harmful effect. If the cables are loaded cyclically, having considerable no load or low load periods followed by short overload periods, the current carrying capacity is comparatively higher than the normal current rating. However, this has to be worked out based on the actual working conditions.

Back to top

Cables exposed to Solar radiation:

To reduce the effect of solar radiation it is recommended that the cable should be shielded from the direct rays of the Sun without restricting the ventilation. On account of hating of the exposed cable due to solar radiation the rating of the cable installed out-doors and not shielded from the Sun is less if shielded. It is advisable to shield the exposed portion of the cable route from the direct rays of Sun instead of using larger size of cable for the entire route.

Bending Radius:

While installing TROPOTHEN-X Cable, the following minimum bending radius should be observed, so that the cable and especially the insulation is not damaged. Wherever possible larger bending radii should be used.

Where D is overall diameter of the cable

Back To Top