Hi jabber71 and welcome to the boards. What cameras are you using? Check out this thread (http://www.x10community.com/forums/index.php?topic=9649.0) on running extention cords. It has a print on how the plugs need to be wired.
Also as far as how long you can run wired cams, I have tested runs up to 310 feet and had no problems.
(http://www.bdshost.com/X10/lpup.gif)---(http://www.bdshost.com/X10/lpup.gif)---(http://www.bdshost.com/X10/lpup.gif)---(http://www.bdshost.com/X10/lpup.gif)---(http://www.bdshost.com/X10/lpup.gif)----KDR