I have a 12 V regulated power supply that I use for a car audio amplifier in my home and I only have it hooked up with a cord that has a line and a neutral, no ground. Could this be dangerous or cause any other issues? It's been working fine so far and I don't get a shock when I touch the case of the power supply.

apologies for poor image quality

  • 3
    \$\begingroup\$ Is the 12V supply double-insulated? (Does it have the double-insulated symbol, a square box inside another one, on its label?) Double insulation is the standard way to ensure safety without a ground. \$\endgroup\$
    – user16324
    Commented Jan 23, 2018 at 21:08
  • \$\begingroup\$ Helpful: Why don't we use neutral wire for to ground devices and earth wire for closing the circuit? \$\endgroup\$
    – user103380
    Commented Jan 23, 2018 at 21:14
  • \$\begingroup\$ Can you post pictures of the power supply and cable you're talking about? \$\endgroup\$
    – vofa
    Commented Jan 23, 2018 at 21:17

2 Answers 2


Quite simply, they provide an earth connection so it requires connecting to earth.

The safety earth is there to protect you, and also the equipment, in the event of a fault that connects a dangerous voltage to the chassis and metalwork.

The fact that no such fault has happened so far does not stop it happening in the future. On the day it happens, if at all, you'll need the safety earth. The consequences of not having it range from pain to serious harm to death.

Take no pointless or easily-avoidable chances. Use a proper mains cable with earth and change the risk from unlikely or improbable to nigh-on impossible.

It's a good lifelong habit to adopt and will cost you all of about £2 for a cable.

  • 1
    \$\begingroup\$ Thanks a lot for the info, will definitely invest in a proper cable! \$\endgroup\$ Commented Jan 24, 2018 at 14:00

Some appliances may give a shock if there's a wiring fault. Some, will only give a shock if there's TWO wiring faults. Each may be safe if there are no faults.

But, local safety standards (which differ according to century and region) may require... almost ANYTHING.

If you might touch the 12V output wiring of the power supply, and if there is any hazardous AC voltage involved, a ground-fault interrupter (GFI, or GFCI) and the two-prong plug should make the system shock-safe. Any modern three-prong power plug has a ground that would also make the system shock-safe (if the design passes modern safety standards that I'm familiar with).

There is no absolute safety, so there's no possible complete answer to this question. Notably, even if there's NO AC power involved, batteries have been known to catch fire.

  • \$\begingroup\$ Thanks for replying so fast! I'll get a grounded cable to avoid any risks \$\endgroup\$ Commented Jan 24, 2018 at 14:03

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