In Eagle CAD, in a 4 layers board (signal-ground-power-signal) how do I avoid that a through hole via from, for example, the top signal layer to the power layer is electrically connected to the layer in between (ground)?

Do I need to manually move the ground polygon or overlay a "cutout" polygon or can it be done automatically? Can Eagle CAD place a cutout or a no-copper space around the Via on the in-between layer?



1 Answer 1


You don't need to worry about it since your netlist will take care of that. If your via passes through a plane or copper pour that is not in the same net, a cutout will be made around the hole in the plane so the via does not make contact. These cutouts might not appear until you actually connect your polygon to a net.

It's almost the exact same thing as routing a trace through a polygon or copper pour that is connected to a different net. Cutouts will be made in the polygon around the trace.

It should take ZERO additional steps on your part. Just route as normal.

Can you imagine having to deal with that manually on a board with hundreds or thousands of vias? And with modifications that could occur? Any software that did not automate that would immediately die even if it was free.

  • \$\begingroup\$ Ok, thanks DKNguyen, that's good to hear! \$\endgroup\$
    – haku15
    Jul 23, 2019 at 23:06
  • \$\begingroup\$ They might also not show up until you do a ‘ratsnest‘ command to rebuild the polygon pour, after doing that you should be able to turn layers on/off to see the cut outs. \$\endgroup\$
    – Ron Beyer
    Jul 24, 2019 at 0:22

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