Is it safe to connect external screen to MacBook via USB-C from the warranty perspective

Since power is supplied to the MacBook there is a (small) risk to damage the laptop. How does it stand from Apple's warranty perspective? Do screen manufacturers such as Dell or LG have any agreement with Apple? Technically, we're plugging in a non-standard power adapter; can it void the warranty? Edit: By "non-standard" I meant "non-Apple".