K.25：光缆的防护-(199605)

刘跃龙

Construction characteristics of the cable光缆的结构和特征 This Recommendation applies to the following types of optical fibre cables:本标准适用于以下类型的光缆 – –type A: cable with dielectric core but having no metal elements (dielectric or metal-free cable); 类型A：采用电介质芯线，但无金属部分的光缆（电介质，或无金属光缆）。 type B: cable with dielectric core and metal sheath or sheaths – there are no metal elements in the core of the cable which has a metal sheath (for example the moisture barrier) or a metallic supporting wire 第二类型B：有一层或几层金属屏蔽层与电介质芯线的光缆：芯线中没有金属成分，但是有金属屏蔽层（如防潮层）或金属支撑线。 type C: cable with metal elements in the core and with a metal sheath or sheaths – there are metal elements, such as conductors or strength members, in the core of the cable which has one or more metal sheaths; 类型C：有一层或几层金属屏蔽层,芯线中也有金属芯线的光缆：芯线中有金属线，比如导线芯或金属加强芯。 type D: cable with metal elements in the core and without a metal sheath 类型D：没有金属屏蔽层,但芯线中也有金属芯线的光缆。 For cable types B, C and D, the value of failure current (Ia) shall be evaluated, except for cables with more than one metal sheath. 光缆类型B，C和D需要估算故障电流(Ia)的可能值 5.2 Failure current for buried cable or aerial cable with earth connections of the metal sheath地埋或架空光缆金属屏蔽层与地连接的故障电流