Wiring - what to do with negative wires

[Kate W]

Wiring question - so, I added this larger fuse panel to make room for 2 new 12v accessories. The existing negative wires all go to marrette in a switch box that is labeled “UP for 110”. Should I bring the new negative wires here (already a bit crowded), or somehow patch down to the fuse panel, and bring the negative down to there? Seems like it should be the latter?

[JoelInTexas]

One common solution is to install a negative "buss bar" for all the added 12 volt accessories - and then connect it to an existing ground point.

Here's an example.