Multiple power supplies — can I avoid the ERC error?

Say that I have two DC/DC converters, one to generate +5V, one to generate +3.3V; both with respect to the one and only ground reference.

I need to connect the negative terminal of each converter to GND. But each of those terminals is a pin of type Power Output, so I get an ERC error.

Is there a way to avoid this error? (without jumpers or 0-ohm resistors or net-ties)

If at least one DC/DC is non isolated then i would change the negative “output” to power in (as it is not really a power output in that case but just a connection to its input side, “output” pin could even be stacked with input pin in that case and symbol drawn as a 3 pin device).

If it is however an isolated DC/DC then it becomes a bit different. Here one option is to simply ignore this one ERC error. See it as KiCad telling you “something is fishy, please take a look”.
Another option is to place any passive device or even a net-tie in series (might even be a good idea when connecting two isolated DC/DCs together as they might otherwise start to fight a bit potentially increasing power requirement or even creating EMC troubles).
Or change one of the power out pins to power in by creating a project specific symbol for the one you consider “not the true source of GND”.


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