But a twist is not sufficient for ground wires without a crimp ring or other listed device, so I don't see how it would be acceptable here, either.
But it is sufficient
250.8 Connection of Grounding and Bonding Equipment.Grounding conductors and bonding jumpers shall be
connected by exothermic welding, listed pressure connectors,
listed clamps, or other listed means. Connection devices
or fittings that depend .........SOLELY ON SOLDER........ shall not be used.
Twisted together and soldered is different than relying solely on solder.
