I'm planning to completely wipe my PC, which has two SSDs, and perform a clean Windows installation. I've heard it's safer to disconnect any drive that won't receive the operating system so the installer doesn't accidentally use the wrong one. Should I erase or format the secondary SSD before disconnecting it, or will it be wiped automatically when I reconnect it after Windows is installed?
3 Answers
No, the secondary SSD won’t be wiped just because you disconnect and reconnect it. A drive is only erased or formatted if you specifically choose to do that during the installation or from within Windows.
You don’t need to wipe the second drive beforehand. Back up anything important, unplug the secondary SSD while installing Windows on the primary one, then reconnect it afterward. You can format it later in Windows if you decide you no longer need its data.
If you don’t need anything stored on the second SSD, you can format or delete its partitions from the Windows installer’s drive-selection screen. Otherwise, leave it alone and disconnect it before installing Windows. That also prevents accidentally selecting the wrong drive.

The main reason to disconnect it is avoiding confusion during setup, especially if both drives have similar capacities. It isn’t required for the drive to be erased.