Each cable conductor must be #18 AWG (0.82 mm2) or larger except -
(a) Each power and lighting cable conductor must be #14 AWG (2.10 mm2) or larger; and
(b) Each thermocouple, pyrometer, or instrumentation cable conductor must be #22 AWG (0.33 mm2) or larger.
[CGD 94-108, 61 FR 28280, June 4, 1996]