NEC 690 - Covers PV Systems

690.45 - size of PV equipment grounding conductors - Table 250.122 + no less than 14 ga.
690.9(A) says that we don't need overcurrent device for PV if the wires can handle short current capacity of PV. But good luck trying to convince a code official.
PV Grounding PDF [1]. Although the NEC does not specifically require all equipment to be certified/listed, many local jurisdictions and many AHJs establish requirements that all equipment be certified/listed because they feel unqualified to examine uncertified/unlisted equipment for safety as the NEC requires.

Equipment Grounding

PV panels should follow electrical grounding conductor sizes - [2]
Ie, for 30A DC, we need 10 ga ground.
PV frames must be connected to PV system equipment grounding conductor [3]
After leaving the PV array, the equipment ground must run together with the power wires. [4]

Australia rules - appear to say 6 ga for lightning protection, and 12 ga for frame grounding [5]
6 ga USA if 'subject to damage'?