Debian partitioning and advice

[pallid delta]

I've been using Linux for about 5 years to a semi-advanced level, I am familiar with all the major aspects of the command line and all of that, by no means a beginner, I have been on Fedora for about 2 years now and I haven't distro hopped since then.

I have a seperate home and root partition, and multiple hard drives.
So, my questions are, in the Debian net installer iso, how do I only tell Debian to install on my /root partition, what're the consequences of only doing this (leftover fedora files etc), and how do I make sure that none of my other hard drives and /home partition are formatted, and potentially, do they need to be?
Thanks

I've read the relevant Debian wiki pages and etc but it doesn't necessarily clarify it as much as I would like, so I'd appreciate any advice or more relevant wiki pages I may have missed.

[iron egret]

/root and / are two totally different things.

/root is the root user's home folder. There's no reason whatsoever to install debian to a home folder.