The power and grounding terminals and field termination points on the I/O subsystem and the system power supplies are designed to accept 2.5 mm2 (14 AWG) stranded or solid wire. To select wire, calculate the maximum current limit expected for each wire. Local electrical codes define the wire size required for a specific current.
Shielded twisted pair wiring is recommended for low-level signal wiring to reduce susceptibility to noise. You can order an I/O carrier with a shield bar (to terminate the shields from field wiring) or without a shield bar (where termination is not necessary).