I think the correct solution is to make use of project .gitconfig files. When you use git it looks for a local .gitconfig, it that doesn't exist, it looks for a global .gitconfig.
So in your case, you could create a local .gitconfig whenever you are using your personal repos and rely on the global config for work.
See for example https://coderwall.com/p/wkqf9q/local-global-git-config