Millisecond delay connectors for det cord may be fired by what event?

• A. A loud bang
• B. A magnetic field
• C. A temperature change
• D. A falling rock

Answer: (A)

Millisecond delay connectors are used to create precise timing between detonations along a detonation cord. They’re activated by the blast event itself—the explosion of the initiating detonator at the front end sends a shock that travels into the delay element, and after the programmed millisecond delay, it triggers the next section. In other words, the ignition comes from the initial explosion, which is heard as a loud bang.

A magnetic field, a temperature change, or something like a falling rock wouldn’t reliably initiate the delay in the cord, so those options don’t fit how these delay connectors are designed to be fired.