Ground Plane Setup

I seem to be missing something obvious but searches so far have proved fruitless.

I’m trying to create a proper set of power and ground planes. I’ve found many references on creating copper pours on two layer boards to provide a plane but nothing on creating power and ground layers.

I’ve set up layers named VCC and GND and tagged as power but all device pins are showing ratsnest connections when I’d expect they should just connect to the plane.

As I said the only tutorial or help refers to setting up copper pour areas, nothing on setting up the layers to act as power planes.

I expected quirks switching to KiCad but this one has me stumped.


And what do you think “layer acting as power plane” is but a copper zone that spans the whole board on that layer?

After you setup that zone all the pads on same net will get connected if the zone is on the same layer AND it can reach them. If other traces cut the zone off or your clearance settings don’t allow it to squeeze where needed it may not reach your pads, in which case you need to move things around or drop a via or two.

Also if the zone is visually connected to the pad but you still see ratsnest line run DRC, it usually triggers connectivity recalculation and those lines should go away. If it doesn’t that means one or the other end of the ratsnest line is not connected, check both.


Add filled zone, select your layer and net, assign priority and draw it.
By default filled zones connect to pads using thermal reliefs. The default settings for these don’t allow connection to fine pitched SMD ICs

I did not comprehend your post, as it is so simple that I could not understand where the misunderstanding could be.
So I became a bit curious, and had a look at your other activity and found:

Maybe you are mixing a “polygon” with a “copper pour” or zone. (Those are the same).

A polygon in Pcbnew is just a graphical element. For a copper pour you need to create a zone:

Pcbnew / Place / Zone.

And then, the first thing Pcbnew does (after you click on the screen) is to which net the zone must be connected. Zones for power connections should of course be connected to the nets of those power nets :slight_smile:

Yeah, there’s clearly a communication issue that is at least part of the issue. I thought what I was requesting was both obvious and routine. The root of the issue may be terminology. At least some of the replies seem to be telling me about how CU pours work. I don’t want CU pours, at least not on a signal layer.

Let me expand a little. I have a fairly standard four layer setup. Starting from top to bottom I have signal, Vcc, Gnd and signal. The two inner layers are named Vcc and Gnd and tagged as power layers. As such I expected any through hole pin or via belonging to a Gnd or Vcc net would connect to those layers automatically. That is, however, not what I see.

It’s looking like there’s no Cu on the inner layers. They’re set up as power planes though so I don’t see why that would be the case. Maybe I have to set them as power planes somewhere else? But if so why have the setting in the layer setup? That’s certainly the logical place to set a layer as a power plane layer rather than a signal layer.


Yes, but I’ve already flagged the plane as a power plane. It should be a zone but nothing seems to connect to it


Setting layer as power plane doesn’t do anything in KiCad, maybe it will in the future.
You still have to add copper zone and assign a net to it.

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Aha, so I actually have to add a polygon of CU to the layer? That’s somewhat counterintuitive to me (and not apparent from the documentation).


Not a polygon, a zone.

Ok what’s the difference? I’ll probably take a look at that tomorrow.


Polygon is just a simple graphical element you can draw on Cu layer as well as silkscreen and others. Zone is copper only, can be assigned a net and is an object that KiCad will reshape as needed to connect to things that should be connected and avoid things that shouldn’t. When you modify the board you just press ‘b’ to rebuild zones and they will reshape again.

Thanks, I’ll start figuring this out in the morning. You’ve saved a few hairs on my head, my scalp appreciates it.

Finding out that I need to create the power planes manually was the biggest puzzle piece I needed.


I just wrote a short FAQ article:

EDIT: you can give feedback in this thread so that the FAQ thread is kept clean.
Edit2 by @Rene_Poschl: moved feedback to separate topic to keep this one on topic for solving the problem at hand.

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3 posts were split to a new topic: Discussion FAQ topic: Ground Plane Setup

Thanks gentles, this was what I needed to understand what KiCad was doing.

And @eelik, thanks for setting up the FAQ, hopefully that’ll help others that have that particular blind spot.


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