Along the lines of what ElectricAL and Trumy have already said, you might want to investigate if the previous installer/owner "piggybacked" or tied together and neutrals from separate branch circuits.
(Easy way to tell - open the main panel board (breaker/fuse box) - if there are x # of circuits listed (with x# of corresponding fuses or breakers), there should be an equal number of neutrals tied into the neutral bus bar - not x# minus a few)
It's also possible that the newer appliances, while higher efficiency, are operating at a higher amperage than the equipment originally spec'd for the installation... maybe somebody switched a 50a dryer receptacle for the original 30a without re-wiring with larger conductors - that's a research and calculation call, to ensure your conductors are the right capacity.
Good luck!
[This message has been edited by DougW (edited 09-27-2003).]
