内衬绝缘材料的贱金属制线路导管及其接头。
导线管用弯头，衬裹绝缘材料的，贱金属制。
1·In a skyscraper, virtually every pipe and electrical conduit is designed (though the positions of the walls sometimes aren't!)
事实上，一幢摩天大楼里的每一根管道和电缆管都要设计(尽管有时不设计墙的位置！)