Wire size and voltage drop
The gauge is not the answer to anything on its own. Two metres of 28 AWG to a motor pulling an amp loses most of a volt, there and back, and the board at the end of it is not faulty.
0.053 V
53.0 mΩ/m × 1 m × 2 × 0.5 A = 0.053 V lost
Gauge — 22 AWG, 0.64 mm across
Area
0.326 mm²
Resistance
53.0 mΩ/m
In free air
7 A
In a bundle
0.92 A
0.053 V gone in the wire, counting both legs of the run — the return conductor is the half people forget. That is small enough to ignore at a 5 V rail, though not at 3.3 V if it grows. 0.5 A is inside both ratings for 22 AWG.