@jea48 - "You don’t need a closed circuit to have a difference of potential, voltage.
If you connect a pair of wires to a source at the end or anywhere along the pair of wires the difference of potential exists." Isn't that why these work? https://www.fluke.com/en-us/product/electrical-testing/basic-testers/fluke-2ac
If you connect a pair of wires to a source at the end or anywhere along the pair of wires the difference of potential exists." Isn't that why these work? https://www.fluke.com/en-us/product/electrical-testing/basic-testers/fluke-2ac