I don’t think that there are many people actually describing the experience of detecting current flowing through the power cords of ordinary equipment. I think there are many people who are interested in magnet implants talking about the idea of detecting live wires. The distinction is level of specificity. I searched through the biohack forum and pretty much every post describing sensing wires also said only very high current situations.
You were asking about PCB traces, which is pretty specific. As an EE I can give you a more detailed rundown.
No sense:
DC power, lamp, television, laptop charger cord, desktop computer cord, pretty much any PCB trace
Sense:
Heating element cord, pulses (when you first turn on a device), erratic power draw (fluorescent lamp), transformers (including those in AC/DC power bricks)
I’m speaking mostly from my experience with dedicated sensing magnets. My data on xG3 sensing will be skewed, because it is implanted in my tragus. Better to rely on Vicarious or another for that. I have tried to sense with it, but there aren’t as many nerve endings there as there are in the fingertip and it’s kinda awkward to “listen” to things that are potentially high voltage 