Electronic – Ground/Earth connection missing on power strip

^{simulate this circuit – Schematic created using CircuitLab}

Figure 1. Suggested earthing point.

As this isn't a commercial project your primary concern is to keep the system safe for you and other occupants of the house. Dry wood is normally a good insulator but if it gets wet the situation changes. You also need to consider any other possible electrical paths out of the enclosure: for example, is the transformer bolted to the chassis and can the bolts be touched from the outside?

You could consider earthing the transformer frame as a safety precaution. This will

• blow the fuse or trip your RDC (ground-fault detector) should the transformer frame ever go live.
• earth any transformer bolts protruding though the case.
• trip your RCD should the case get wet.

There are two ways to get a shock from such a setup:

1. Connecting to the live circuit. This is unlikely as there would have to be insulation breakdown of the live conductor, the CT and the CT wire insulation.
2. A shock from high voltage generated by the CT during measurement. Theoretically this is possible on an open-circuit CT when significant current is flowing in the primary. In practice it doesn't seem to be much of a problem in small CTs. To get a shock you would need to touch both terminals simultaneously. The shock current would flow from terminal to terminal through your body and not to ground (through your feet mentioned in the question).

Is it safe to touch all the connectors of the audio jack, with my feet touching the ground and the mini-CT attached around an AC live wire that's currently drawing a current?

Bare feet? No, not safe for any work near mains. You should be wearing decent work shoes.