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I have four 12V DC power supplies powering four separate loads (12V LED light strips). Is it safe to use a common return path for all four loads?

schematic

simulate this circuit – Schematic created using CircuitLab

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  • \$\begingroup\$ Yes, in the level of abstraction you ask, it can't be a problem. However, current load questions arise that depend on your cabling, and noise questions that depend on your power supply. Since you specify neither, no specific answer is possible. \$\endgroup\$ – Marcus Müller Aug 2 '19 at 16:13
  • \$\begingroup\$ Please post more details about the DC power supplies: battery, unregulated transformer + rectifier, linear regulator, switching converter... \$\endgroup\$ – vangelo Aug 2 '19 at 16:20
  • \$\begingroup\$ Yep. No problem. Go for it. Just make sure the common path has good current capability. \$\endgroup\$ – Kripacharya Aug 2 '19 at 16:22
  • \$\begingroup\$ OK, assuming that they are dumb LED strips. If they are programmable LED strips, the ground reference for the data signal(s) could be an issue. You need to draw out the entire circuit if you are using programmable LED strips. \$\endgroup\$ – Mattman944 Aug 2 '19 at 17:58
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It depends on the total current and what the cable is rated for

Let's say each 12 V LED strip consumes 12 W, then each LED strip has 1 A flowing through it. For each LED strip, the ground wire needs to carry 1 A, from left to right in your schematic it will show 1 A, 2 A, 3 A and 4 A at the bottom.

Given my 12 W example you need a cable that is rated for 4 A, since you have 4 LED strips and 1 A per strip. According to powerstream you need 15 AWG or you can have several cables in parallel with higher AWG values.

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