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I want to control some WS2811 lights with a Raspberry Pi.

The lights need 24V ~180W ~8A from a supply such as this, whereas the Pi wants 5V and presumably low power from a supply such as USB. I believe both these supplies are switched-mode DC.

Tutorials show the Pi and lights sharing a common neutral line, i.e. the DC 0V output line. (The lights have no ground.) However, they also share a 5V power supply.

If the lights and Pi are to have separate supplies, is it safe and correct to tie the neutral lines?

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  • \$\begingroup\$ "Neutral" applies to AC power lines. I hope you are not connecting the Pi straight to the mains neutral. \$\endgroup\$
    – JRE
    Oct 5, 2021 at 12:20
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    \$\begingroup\$ Tutorials show the Pi and lights sharing a common neutral line. They should show a common ground line. That doesn't mean that ground is connected to mains earth. There is no need for that. Don't connect ANYTHING to any AC mains (wall socket) unless you know what you're doing. If you have to ask, you don't kno (yet). There is no need to use anything else than the connections from the outputs of the power supplies. Indeed you should connect the grounds of everything (Supplies, LEDs, RPi) together, you will have issues if you don't. Follow the tutorials! \$\endgroup\$
    – Bimpelrekkie
    Oct 5, 2021 at 12:33
  • \$\begingroup\$ By "neutral" I mean the DC 0V output line, not the AC mains. \$\endgroup\$
    – spraff
    Oct 5, 2021 at 13:36

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The common grounds need to be connected, but you should avoid sharing the wires to the power supplies. The common connection should be close to the destination, not the source. You don't want current spikes in the 24V common wire to affect the 5V power.

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