...voltagedrop between the pin on the PTW and the ground near the groundpoint on a LOADED circuit. Measuring resistance or continuity is useless for anything but a dead broken wire or an aaaalmost broken wire (if there is a spot in a wire that have corroded inside the insulation and there are just some green powder left inside you can often meassure close to the right voltage on an unloaded circuit but it drops to 0 volts as soon as you try to draw some amperage through it because of the big resistance)
