Wrong capacitor connections

I have some bog standard SMD capacitors and all of a sudden pcbnew draws thin white lines between pin 1 & 2. This means that 3.3V is now connected to GND through the capacitor and pcbnew is now totally confused.
I tried deleting and re inserting but same result.

What did I do wrong and how can it be fixed?


We see this question often. The two most common reasons for this in order of likely hood. Not saying this is your problem but for the number of threads we see on this… :wink:

You actually have ground and 3.3V shorted somewhere in the schematic.

The rats nest lines are straight and sometimes will run straight though another part and look like it belongs there. Moving the part around will help visualize if that is the problem.


Ratsnest between both pins may also mean footprint is rotated 180* . This may happen if you for example changed your footprints with ones that have Pad1 & Pad2 swapped (or if the symbol have been updated accordingly). But as @hermit explained, dragging the affected part should reveal the true cause.

Dragging is not what i really would use to be honest. A better and more reliable option is the use of the highlight net tool. It will highlight all pads that are considered connected. Moving stuff around to see connections is too error prone as it relies on you moving it in just the right way to see the true connections.

Same holds true on the schematic side. Use the highlight tool there to see if your two nets are connected.

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I did just that - but in a (to me) surprising way.
I have two I2C connections on the board. I used standard connectors so I couldn’t label them directly and instead labeled the connecting lines. The BME280 has a SDO input to change its address. So I had one connected to ground, the other to 3.3V. But they both got the ‘SDO’ label which KiCAD duly connected… I renamed them to ‘SDO1’ & ‘SDO2’ and everything was alright again.

I think I should use text instead of labels for this purpose in the future.

Thanks guys for the help!


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