Question: Why would you need to pass power through a splitter?
Answer: To feed DC Voltage to an In-Line Amplifier. You know how the TV's you are feeding are never the exact same distance from the House Antenna, or where the Cable TV hits the side of the house? Well, if the distance is an extra hundred feet (Maybe you got TV in the Garage!), you may need to amplify the signal. The Power Passing Splitter allows the DC current to feed through this one leg of the Splitter so you can place an In-Line Amplifier where you need to without having to worry about a power outlet location. These Amplifiers also come with a Power SUpply that can be located indoors, put DC Voltage on the Coaxial Cable, and feed the current throught the Splitter to wherever you have that small little In-Line Amplifier.