Normal mains-voltage (240/110 volts) is easily sufficient to cause a shock, that's unpleasant and potentially somewhat dangerous, but because of the resistance of skin which can be anywhere between 5KOhms to several million Ohms, the current flow is usually insufficient to cause any tissue damage.

The skin's insulating ability is the body's greatest protection against shock, the standard voltage thought to be sufficient to breakdown the skin's resistance would be 500v, now 1000 volts would likely cause fine puncture wounds in the surface which would then allow high currents to flow within the tissues itself causing tetanic contractions of the muscles (and as it's direct current, a grip you can't let go), heating, carbonization of channels through the flesh and the flow of very large currents, eventually eating away through the flesh creating a crazed fractal pattern:

^{https://cutthewood.com/ Fair usage 2021.}

There would be out-gassing as the flesh burned, probable bloating, like the skin on a chicken that gets a gas bubble when you take it out of the oven. Then smoke as the flesh burns.

Eventually the flesh would lose integrity and tendons would detach, or finger joints allowing the hand to be pulled free. There would be lots of permanent damage to flesh, sensory nerves and muscles of the forearm.

Speculation:

It's possible, maybe just possible, that if the person who's hand touches the electrodes has engaged in lots of manual work and has very thick skin - like a builder or even gymnast, that the skin will be thick enough to prevent breakdown for a while, meaning, if the skin is dry there'd be a painful shock and tetany (and gripping if they were unlucky), but they might get away with little more than a pain memory.

If there were gripping, they might have several second or even minutes to cut the current/free the hand before the skin did break down (which it would do eventually).

Normal mains-voltage (240/110 volts) is easily sufficient to cause a shock, that's unpleasant and potentially somewhat dangerous, but because of the resistance of skin which can be anywhere between 5KOhms to several million Ohms, the current flow is usually insufficient to cause any tissue damage.

The skin's insulating ability is the body's greatest protection against shock, the standard voltage thought to be sufficient to breakdown the skin's resistance would be 500v, now 1000 volts would likely cause fine puncture wounds in the surface (at first, they'd spread fast) which would then allow high currents to flow within the tissues itself causing tetanic contractions of the muscles (and as it's direct current, a grip you can't let go), heating, carbonization of channels through the flesh and the flow of very large currents, eventually eating away through the flesh creating a crazed fractal pattern:

^{https://cutthewood.com/ Fair usage 2021.}

There would be out-gassing as the flesh burned, probable bloating, like the skin on a chicken that gets a gas bubble when you take it out of the oven. Then smoke as the flesh burns.

This would take no more than a few seconds. A Kilofarad capacitor charged to 1000v would discharge pretty fast - so the outgasing might be quite dramatic, and you would see the skin glowing orange as it carbonized. This video illustrates, though it's a low current source, the effect on flesh would be faster and more dramatic, and glow brighter (though I've not tried it myself, there'd likely be many small jets of flame-like plasma after the initial steam).

The flesh would lose integrity and tendons would detach, or finger joints allowing the hand to be pulled free. There would be lots of permanent damage to flesh, sensory nerves and muscles of the forearm.

Speculation:

It's possible, maybe just possible, that if the person who's hand touches the electrodes has engaged in lots of manual work and has very thick skin - like a builder or even gymnast, that the skin will be thick enough to prevent breakdown for a while, meaning, if the skin is dry there'd be a painful shock and tetany (and gripping if they were unlucky), but they might get away with little more than a pain memory.

If there were gripping, they might have several seconds or even minutes to cut the current/free the hand before the skin did break down (which it would do eventually).