You can set ethernet as a metered connection in the registry and the Winaero Tweaker tool can do it for you. However, when I did it, I found manually initiated windows updates stalling on "Downloading Updates 0%" so I don't recommend that solution.

Instead, configure a group policy as documented below.

https://support.microsoft.com/en-us/kb/328010

Note that Windows respects the "download only" policy but does NOT respect the "no reboot after updates" policy. To stop Windows from rebooting after installing updates, follow steps labeled #2 at the link below.

https://superuser.com/questions/973009/conclusively-stop-wak...