It's not uncommon to get a voltage reading when referencing unbonded items such as metal parts that are bolted to a concrete wall where the reenforcing mesh is actually part of the buildings system ground as all the structural steel is tied into the ground system. The main focus of the video was to showcase that unbonded metal is going to give you a very erratic meter reading which tends to confuse most people who are just learning about electricity. In this case, the transformer was producing about about 132 volts but when taking a reading while using a piece of metal that was not grounded to the building's electrical system, we got a much lower reading. I hope you found this helpful.