"暗线装置系统" can be translated into English as "concealed wiring installation system" or "hidden conduit/wiring system".
"Concealed wiring installation system" emphasizes that the wiring is installed in a hidden or concealed manner, typically within walls, floors, or ceilings.
"Hidden conduit/wiring system" similarly conveys the idea that the conduits or wiring are not visible, as they are concealed within the building structure.
Both translations are accurate and commonly used in the context of electrical installations where the wiring is not exposed for aesthetic or safety reasons.