Scotchloks for Backup Camera Systems video
More about this system
Here's how it works: Scotchloks have two 'channels' to place wires. Simply place the Scotchlok around the wire you want to tap into, then in the second channel place the wire from the device you want to supply power to. Finally, press the small metal tapper down into the Scotchlok and it will connect the two wires without severing either!
If you want to be able to uninstall your backup camera system at some point in the future, Scotchloks will not only make it very easy, it will leave the original system intact and unaltered.