| 摘要 |
The plastic, e.g. PVC, trunking (1) has, in cross-section, the form of a U or several adjoining U shapes to segregate cables of different types, such as power and communications cables. A flat cover (2) is held on by press-fit or other fixings (3). In trunking channels which require screening, the walls (5) and cover (6) contain a central metallic foil (7) introduced during extrusion. Optionally they are lined internally with metallic foil. Copper or aluminium, plain or alloyed, may also be used. Submerged foils, brought out along the edges of trunking and cover, are in electrical contact when the cover is fixed and lining foils similarly overlap to complete the screening. ADVANTAGE - Effectively screens cables though it is only slightly dearer than all-plastic construction.
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