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I have a root sheet like the following, and I'm having issues figuring out how to properly define separate power nets for each hierarchical sheet.

As in the image below, I have two circuits separated by a connector.

How can I keep the power nets of these two circuits separate?

Root Sheet

My current attempt at this was to do the following in the sub sheet, but it doesn't seem to work since my understanding is that the default power nets are global (are connected across sheets).

Sub Sheet

If this isn't possible, should I be creating a new project for each separate circuit?

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If You really want to separate power nets the solution is quite simple: just give them different names and do not connect them together on any of the projects' sheets.

You've already connected +5V and GND directly to Clock Generator and I assume You also use the same net names on Clock Generator sheet. Next, P38 and P40 are connected to Memory Unit sheet - to this point it's fine, You have separated nets. Now You have to give different names to power nets on Memory Unit sheet, for example +5Vmem and GNDmem.

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  • \$\begingroup\$ Or instead of a power component (like 5V or 12V) simply use a global labels and add a power flag to them. \$\endgroup\$ – GAttuso Aug 30 '17 at 7:19
  • \$\begingroup\$ How do you rename a power net? When I try to edit the field value of a power component it is greyed out. Should I just use generic net lables? \$\endgroup\$ – kkliebersbach Aug 31 '17 at 11:38
  • \$\begingroup\$ Use generic net and add power flag, as @GAttuso suggests or just use another power net from library - there are plenty of them in standard KiCad library. \$\endgroup\$ – Jakub Rakus Aug 31 '17 at 17:27
  • \$\begingroup\$ Awesome, thanks. I think I'm getting on the right track however when I add power flags to different hierarchical sheets ERC complains that power outputs are connected together, even though the nets have different names. \$\endgroup\$ – kkliebersbach Sep 4 '17 at 4:56

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