mains plug fuses, earths, etc...

hi folks,

question i have always wanted to ask but was shy: why are fuses in mains plugs considered a "bad" thing sonically? extra impedance because of the "thinner" fuse wire??? signal refelections caused by change of impedance?? or what???

talking about mains, does someone have a schematic of the relationships between mains earth and signal earths in a system consisting of 52, supercap, 250, cds1 or 2, and lp12/prefix powered via 52 input 2b. might help me to understand a few things.

enjoy

ken