Detonating cord (also called detonation cord, detacord, det. cord, detcord, primer cord or sun cord) is a thin, flexible tube with an explosive core. It is a high-speed fuse which explodes, rather than burns, and is suitable for detonating high explosives, usually pentaerythritol tetranitrate (PETN, Pentrite). The velocity of detonation is sufficient to use it for synchronising multiple charges to detonate almost simultaneously even if the charges are placed at different distances from the point of initiation. It is used to reliably and inexpensively chain together multiple explosive charges.
This is just electric cable and is inert.