Is it NEC compliant to wrap the ground wire from a 14-2 around the sheathing and then clamp it using the NM clamp in a metal junction box? I live in a house built in the 60s and I see that a lot but I don't know if that's sufficient for grounding.
There are two use cases in particular that I'm curious about for this style of grounding.
The first use case is receptacles. Say you have an incoming and outgoing cable both with the grounds wrapped and clamped, then the receptacle is attached to the box with a ground screw (e.g. not spliced to the incoming/outgoing grounds). Is everything grounded properly or does the receptacle need to be spliced together with the ground wires directly?
The second is lighting. Basically the same question; if the cable grounds are wrapped and clamped, can the light be grounded directly to the box or does it need to be spliced with the ground wires directly?
In either case, if you splice the grounds do you also need to have a connection to the box?