Unless otherwise specified, 22 AWG wire is normally sufficient for the power supply and ground
lines, but we recommend that you consult a wire sizing chart to determine the size required for
the wire routing in your particular aircraft. Ensure that the power lines include a circuit breaker
or an appropriately sized fuse for the wire you select.
Smaller gauge wire is sufficient for lines that only carry data.
From page 13-1 if installation manual.
I used 24 AWG for the two twisted pairs.