09-17-07: CheapmikeZinsco, was junk from the get go. They went out of business years ago.
Iv'e noted sizzle or "micro-arcing" from Zinsco brand circuit breakers (common in older houses) you can actually hear coming from the breaker with heavy load applied.
Problem is poor contact pressure between the breaker female slide on connector, of the breaker, and the male breaker aluminum buss tie of the electrical panel buss.
The load presented to the poor connection does not have to be that much to cause micro arcing.
Under High load conditions I have seen where the aluminum breaker buss tie of the panel began to burn it's self free from the female breaker connection.
Any micro arcing can cause EMI noise on the line. Enough arcing will also create RFI.
With a dedicated circuit I am beginning to think the main quality difference is in the straight run of wire instead going through a series of brass screws on receptacles,Daisy chaining the hot and neutral conductor of convenience branch circuits through the receptacles using the stab-lok feature on the back of the receptacle is one of the worse causes of not only micro arcing, but just plain arcing. This type of branch circuit wiring can cause lots of ac noise on an audio system that may be plugged into it. Especially if the equipment is plugged in near the tail end of the branch circuit.
Even daisy chaining the hot and neutral using the side terminals of receptacles can in time cause cause ac noise. With age the copper wire will corrode at the termination.
To this day NEC still allows the hot and neutral conductors of a single branch circuit wiring to be daisy chained through an electrical receptacle device.