When should engineers use instrumentation cable pairs or triads?

Pairs are usually used for two-wire signal circuits, differential signals, and many standard instrumentation loops.
Triads are used where three-wire transmitters, RTD circuits, or specific measurement systems require three conductors grouped together.
The choice affects noise rejection, wiring accuracy, termination method, and maintenance identification.
For process plants, oil and gas facilities, and automation systems, correct pair or triad selection helps reduce signal errors.