6m wide: Use a single run of LHD cable centred above the tray. Where cable is run in external environments standard detection methods can find it difficult and challenging to work. The sensing cable is formed from a pair of twisted steel. tally and vertically providing c tection is easily removed, repEngineered for continuous monitoring and early warning, our cable-based detection system is ideal for protecting cable trays—whether single-tier, multi-tier, or densely packed. It. We are in the middle of a project where we have roughly 60% of all fire alarm (Type FPLP) and telecommunication cable (Cat6A, CMP) is already installed. While all data cable is ran within cable tray, about 20% or so of the fire alarm cable is sharing the same tray.