I have an old PSU which has an output of 18Amps at 12Volts DC. Is it dangerous if I touch the wires? Or is the voltage too low to jump my body (I heard anything below 40 Volts DC can't be felt by your skin).

I won't open the casing of the PSU so I won't come in contact with the charged capacitors.

I'll use the PSU to power a HHO generator

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    \$\begingroup\$ It's not dangerous to you but it could set things on fire if it make contact with something else conductive. \$\endgroup\$ – vini_i Oct 21 '16 at 19:19
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    \$\begingroup\$ The classic example is getting a wedding ring across a high current source and ending up with a really bad burn under the ring and maybe on your other fingers as you try to get it off. \$\endgroup\$ – John D Oct 21 '16 at 20:12
  • \$\begingroup\$ Safe to touch with your skin, yes. But that is not the only hazard. It is enough power to heat up small wires, etc. \$\endgroup\$ – mkeith Oct 21 '16 at 21:33

All voltages below 50V are considered safe to touch.

although I would not advise putting -48V on your tongue to check if a phone line is working as the ring voltage is much higher. ( although I have )

You can try a 9V battery on your fingers then your knee , and you might be able to feel it. Your tongue will feel a strong burning sensation with a quick 9V battery test.

However you can create high voltage spikes with any inductive coil break in current from a low voltage.

Also beware that >4% Hydrogen concentration (LEL) is considered explosive to static discharges in that container.

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  • \$\begingroup\$ He's making "Brown's gas" (a stoichiometric mixture of hydrogen and oxygen). Kaboom indeed. \$\endgroup\$ – Spehro Pefhany Oct 21 '16 at 19:59
  • \$\begingroup\$ So even though the current is 18Amps it's save to 'accidently' touch? \$\endgroup\$ – Olivier Groeneveld Oct 21 '16 at 20:14
  • \$\begingroup\$ @OlivierGroeneveld, Safe for you to touch if you take off rings, watches. But a 12v supply can create sparks that set off Spehro's kaboom when you make/break connections to it. \$\endgroup\$ – glen_geek Oct 21 '16 at 20:59

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