Those of us who work with electricity tend to call an electric cord with the ends stripped bare a “suicide cord” because they are quite dangerous.
I’m going to gloss over a lot of the details here, but basically electricity flows in a big circle. That’s why they call it a circuit. It comes out of the generator at the power plant, goes through all the wires, out one wire of your lamp cord, and then you need to put something that is electrically conductive in between the two wires, so that then it can flow back through the other wire, back through all of the wires in the power system, and back to the generator where it started and complete the circuit. All the switch in your lamp does is disconnect the wire when it’s off, which breaks the circuit.
You can’t just touch metal on someone either. Whatever you want current to flow through has to be connected between the two wires. How much current flows depends on how much whatever you stick in between the two wires resists the flow of electricity. If you just touch the two wires together, there’s nothing to resist the flow of electricity and it will try and draw an infinite amount of current from the wall. This of course is WAY more than your wall can supply, and all you’ll end up doing is tripping the breaker and the power to that circuit goes dead. You’ll get a nice spark and a loud pop where the wires touched too.
Electricity is quite painful, and quite damaging to tissues at higher current levels. If you take two ends of a suicide cord and attach them to either end of a hot dog, you can cook it in about a minute or so.
As a torture device, your suicide cord leaves a lot to be desired. If the torturer accidentally touches both bare wires he shocks himself, and worse, the path of electricity is up one arm, through the chest, and down the other arm (assuming he’s holding one wire in each hand). Shocks through the chest can be particularly deadly, since if the timing is just right, you can throw the heart out of rythm. Once you get the heart into a funky beat, it doesn’t tend to recover on its own, so unless someone is standing there with a portable defib unit and knows how to use it, the torture guy could be dead in a very short amount of time. Lamp cord is made of very flexible copper wire strands, so it would be very easy for someone trying to hold the insulated part to accidentally have the bare wire fold back and make contact with their skin.
Another problem (which is why I’m assuming the guy has a wire in each hand) is that if he accidentally touches the two wires together he just shorts out the circuit and blows the breaker.
I’ll pass on designing you a better torture device. I don’t mind explaining how electricity works, but making a functional torture device is a whole different ball game. Personally, I’d like to see the villian in your book attempt to torture his victim with a suicide cord, accidentally shock himself (while muttering a few choice curse words), then accidentally short the wires together and shut off power to the room. Then you can have him go to the plan B torture device, and do what you want from there.
I should have thought more before posting the second half of the question…obviously, you have no way of knowing that I’m going to use this information for purely fictional purposes.