Jason: Follow the thread on "Don't cut costs on wall-warts..."
Even old-timers have problems!
An old electrician's rule is: When working on the mains, keep one hand in your pocket (no, not for entertainment, but for safety).
In N. A. the wire colour for the 220/240 VAC is red. It is in oposite polarity to the 110 VAC. Same as is the European mains. Essentially they are a balanced (around ground/common) 2x110V supply.
When working on higher voltages please remember the inverse-square-law. Twice the voltage, same resistance = 4x the current. That could hurt! E