Yeah, my vet says to keep new horses isolated far enough away that if they snort or sneeze, the wind won't carry it from one horse to another.
It's actually better to quarantine them away from the barn and main turnouts incase they are carrying something like strangles, which can live for a long time in the dirt in your barn...
So if I were going to quarantine her, I'd quarantine her out front. If she's already really well trained for electric or you have panels that you can setup, I'd keep her well away from the shared fence for a couple of weeks.
It's actually better to quarantine them away from the barn and main turnouts incase they are carrying something like strangles, which can live for a long time in the dirt in your barn...
So if I were going to quarantine her, I'd quarantine her out front. If she's already really well trained for electric or you have panels that you can setup, I'd keep her well away from the shared fence for a couple of weeks.