ITU-T Recommendations

Recommendation ITU-T K.101 contains the calculation procedure for the shielding factors used in Recommendations ITUT K.46, ITU-T K.47, ITU-T K.56 and ITU-T K.97, and it is intended to:
1) provide the rationale for the shielding factor approximate formulas or values contained in the aforementioned Recommendations;
2) allow a more precise calculation of the shielding factors, by using the equations provided in this Recommendation.
The shielding factors considered in this Recommendation refer to:
• that of the lightning current distribution in a telecommunication tower, i.e., that of the tower (αT) as per Recommendations ITUT K.56 and ITU-T K.97;
• that of the lightning current distribution among several conductors placed in a cable ladder, i.e., that of the feeder tray (αF) as per Recommendations ITUT K.56 and ITU-T K.97;
• that provided by the cable tray (β) as per Recommendation ITUT K.56;
• that of parallel conductors (η) as per Recommendation ITUT K.47;
• that of refraction (δ) due to the earthing connection of a telecommunication cable, as per Recommendation ITUT K.46;
• that provided by a telecommunication cable having a metallic sheath (shield) (η) as per Recommendation ITUT K.46.