I'm creating an adapter which hosts two connector types and simply routes two connections from one connector into the other.
- Only two traces/connections are used; Vcc (about 6v) and GND
- Operating current is up to 1A max
- Power is DC only, no signals
So my design uses only one "trace", which is for Vcc, while the ground simply uses the entire ground plane, which fills everything on the PCB other than the Vcc trace, as the return path. Both connectors have pins mounted to the ground plane, so it seems to me like it'll be fine (if not best) to just use the ground plane as the return path instead of creating a trace for it which connects to the ground plane at some point anyway. I've never seen a board use a ground plane as the "primary" return path (with no dedicated trace), though, and I'd like to confirm that this isn't some soft of bad design practice.
Best Answer
The major benefit for using ground planes is that they are used for this very reason.
For instance, any circuit using a "perfect" ground plane guarantees that the local return path of current is directly beneath the forward (non ground) current flow: -
The bottom-line is that current takes the path of least resistance and, for AC currents, the path of least resistance is the path of least inductance.
In your situation any current that returns through the ground plane, flows close to the forward current path. This minimizes loop inductance, thus minimizes generated interference and received susceptibility to interference.
It's just what happens when you use a ground plane - instantly EMI problems are reduced by a large factor.
As mentioned in the picture, it's an example of proximity effect: -