3 pole slide switch. Does it need to have a ground.

Right, simple question. I feel stupid but I’m wondering what is best practice really.

I’m creating a small pcb, just to have a go. It’s powered via 2 AA batteries. On some perf board I used a 3 pole slide switch. Connecting live to the common and pin 1. Pin three was left disconnected.

On a PCB, should the third pin be grounded? Or can it be left disconnected?

EDIT:
I’ve answered my own question here! If I left the pin disconnected, all my grounds will have to go to the battery terminal anyways. So I guess either way is fine.

Are we talking SPDT switch?
If you connect ground to pin 3 and “live” (?) to common, then you run the very good chance of a straight short of your supply, so no, either way is not fine.

I've answered my own question here! If I left the pin disconnected, all my grounds will have to go to the battery terminal anyways. So I guess either way is fine.

Why do you think you might need to connect the negative of the battery to the switch? (You don't).

Have you read common ground and why you need one ? It does not directly answer your question, but it might help. Always ask yourself: "what is the complete circuit?" What circuit would you be making by connecting the -ve of the battery to the spare connection on the switch?

I’m not sure what I was thinking tbh. Had a moment of self doubt and stupidity it seams.

I built it on a bread board and then perf board, which has followed suit onto the pcb. But just suddenly doubted what I’d put.

Cheers

PerryBebbington:
Why do you think you might need to connect the negative of the battery to the switch? (You don't).

Have you read common ground and why you need one ? It does not directly answer your question, but it might help. Always ask yourself: "what is the complete circuit?" What circuit would you be making by connecting the -ve of the battery to the spare connection on the switch?

Excellent article, thank you for directing me to it.