Sorry I am late on this but Short Circuit pointed out 250.122 says you do not need to exceed the circuit conductor size for the EGC, so if the circuit can be #14, the EGC can be #14.
250.122(A) Copper, aluminum, or copper-clad aluminum
equipment grounding conductors of the wire type shall not
be smaller than shown in Table 250.122, but in no case shall
they be required to be larger than the circuit conductors supplying
the equipment.
I am not seeing anything that contradicts this and requires more than #14 if the circuit conductors are #14.
If there is a fault, why should the EGC need to be be any bigger than the circuit feeding the fault?
But I would not let them use type NM to wire a condenser (wet location). If it was UF it would be OK but that is still going to be in a raceway in my patch.
