Detonating cord, also called detonation cord, detacord, det. cord, detcord, primer cord, or primacord, 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. The detonation speed is sufficient to use for synchronizing multiple charges simultaneously even if the charges are placed at significantly varying distances from the primer charge. It is used to reliably and inexpensively chain together multiple explosive charges. Typical uses include mining, drilling, and demolitions.

As a transmission medium, it can act as a downline between the initiator (trigger) and the blast area, and as a trunkline connecting several different explosive charges. As a timing mechanism, detonation cord detonates at a very reliable rate (about 7000 - 8000 m/s), enabling engineers to control the pattern in which charges are detonated. This is particularly useful for demolitions, when structural elements need to be destroyed in specific order to control the collapse of a building.

While it has the appearance of nylon cord, the core is actually a plastic explosive, usually PETN (Pentrite), and it is initiated by the use of a blasting cap. Detonation cord will initiate most commercial high explosives (dynamite, dynamite substitutes, sensitized gels, etc.) but will not initiate less sensitive blasting agents like ANFO on its own. 25- to 50-grain det cord is approximately as forceful as a blasting cap, but along its entire length. A small charge of PETN, TNT, or other explosive explosive booster is required to bridge between the cord and a charge of insensitive blasting agent like ANFO or most water gels.

Rating

Detonating cord is rated in explosive quantity per unit length-- in the United States, "50 grain det. cord" refers to detonating cord which has 50 grains of explosive (about 1/70th of a stick of dynamite) per foot of length.(7000 grains=1 lb, or 1 Gram = 15.42 grain) Precision rock carving work, for example http://www.crazyhorse.org/carving/inside/index.shtml may use 50 to 250 grain detonating cord.

Direct employment

Low-yield detonating cord can be used as a precision cutting charge to remove cables, pipes, wiring, fiberoptics, and other utility bundles by placing one or more complete wraps around the target. Higher-yield detonating cord can be used to cut down small trees; one complete wrap per foot diameter is a rough starting point. Creating a slipknot from detonating cord yields a field-improvisable device that can be quickly employed to cut a locked doorknob off of a door. Anything much more substantial than these uses requires the use of additional explosives.

Unconventional use

Detonating cord has been reported to have occasionally been used during wartime to restrain prisoners if no handcuffs were available; the cord was first demonstrated on a tree or other object, then tied to the prisoners. It has also been used in ambush zones to eliminate enemy taking cover in roadside ditches, bushes, ect.