It's not just Apple laptops that can have this issue; the p.s. circuit breaker trips with a draw of over 75W. If you're attempting to use the computer and charge the battery at the same time, most larger laptops (including the Apple 15" and 17" Pros, many Dells, etc.) will suck up more than 75W. The 13" should require only 65W IIRC, so it won't have this problem.

This is why Apple sells a special EmPower cable, which prevents the large power draw. Unfortunately, there is no such solution for p.s. (regular 110V) plugs, except to either pull the battery (if you want to use the computer) or not use the computer (if you want to charge the battery). If you have a newer MacBook Pro with a non-removable battery... let the battery charge up, then use the machine.