Electronic – My triac turns on when gate attached to vcc (good)… but also when connected to ground (bad)

Moving over to this question as it's related to my answer on your last one:

I checked to see if I could find some info on the CT and I discovered from the datasheet that that model is a voltage output version with a max output of 1V at 30A (assuming pk-pk AC), which means a transimpedance (current to voltage) amplifier is not what you want.
What you want is a simple buffer/level shifter.

Something like this would do:

Waveforms:

If you don't want an inverting buffer then you could try this kind of thing:

If you want to match the range of the ADC then you can add some gain to either. Careful with the inverting version as the DC bias will be amplified. For a gain of 2.5 a ratio of 6 for R5/R4 is needed. Something like R1 = 25k, R5 = 60k, R4 = 10k should be okay.
Note that you need to make sure your opamp is capable of a rail to rail output swing if you want to use the full supply range (an example part from memory is the MCP6021, this does have R2R in/out IIRC)

A couple of things.

A very small point, the UK is in Europe, and AFAICR we have had 3-pin plugs, 3-wire cables, since the late 50's.

My house was rewired in the 80's, and we have Earth Leakage Circuit Breakers (ELCB) on every circuit. So even if I stuck a fork into my toaster while grabbing a copper water pipe, I'd expect it to trip (I am not willing to back this up with evidence :-)

When I have visited continental Europe, I am pretty sure that I've seen the same ELCB technology in use.

I suggest that is even more effective than having an Earth connection; after all, if I touched the correct bit of wire in your toaster with my fork, without touching anything else, the Earth connection via a plug would do me no good. Further, unless the device had a metal case connected to Earth, I don't think I am much more likely to touch both Earth and live than just live alone.

I imagine the cost of rewiring all of the houses in Europe which have two-wire cabling t have three-wire would be very large. However, upgrading the distribution panel with ELCB is pretty simple (a drop in replacement in some cases for an old fashioned fused unit), and could be caused to happen more easily when electricity metres need replacing.