Am I hearing things?

I use a label maker to mark each breaker. One thing i dicovered is the 20 amp single outlet I use from the kitchen to power my stereo has a COMMON NEUTRAL* with another 20 amp circuit which is on the other leg and powers the frig and countertop duplex (toaster over and toaster) I looked up info about common neutral. and seems to be not a big deal unless not known. (ie working on one with the other still alive) Is there any other issues I should know for a COMMON NEUTRAL*                                                     (*For those in the dark a common neutral means one neutral line for two hot lines, with the hot line on different breakers)On The Furutech it is nice I can squeeze the two neutral wire parts in the wall into the same hole. So no gap or running the other line neutral’s power if any, through the Furutech outlet.There is no noticeable noise in my system from the other line. And I have been using this 20 amp outlet for 7 years or more. I just was realizing what a COMMON GROUND was when reading up on it.

Is there any other issues I should know for a COMMON NEUTRAL*

Hi Elizabeth,

The first thing I would wonder is if the neutral wiring that is common to the two circuits is rated to be able to conduct 40 amps, which it would have to if and when 20 amps is being drawn from each of the circuits.

Also, I can envision that sort of arrangement being conducive to ground loop issues in some systems, because the unequal currents in the hot and neutral conductors, and their differing distances from the safety ground conductors, would tend to increase hum and noise voltages that are electromagnetically induced in the safety grounds. (I’m assuming that there are safety ground conductors, and that they are physically close to either the hot or neutral conductors)

Jim (Jea48) is more knowledgeable about this kind of thing than I am, though, especially from a code standpoint. We’ll see what he has to say.

Best regards,
-- Al

Elizabeth  one other thing you might look for the two breakers that share the common neutral need to be ganged. 2  20amp breakers with a common neutral will trip like any other 20amp breaker they won't draw anywhere close to 40amps. The load wouldn't be balanced on the neutral which is what would trip the breaker actually breakers they are suppose to be ganged with the hot on seperate phases. 

I don't get the 25amp breaker on a simple branch to a single 20amp receptacle. Those are not common breakers and are mostly used for AC units and water heaters. You said they did some work on your AC are you sure you're not looking at the AC breaker? If not it should be switched to a 20amp breaker. 

The two breakers are NOT ganged, And I know about the fail on 40 amps. The two sides are ON OPPOSITE PHASE (which I mentioned) so it would be impossible to have 40 amps on the neutral.. What would happen if both legs had 20 amps is: the power would be flowing from line A HOT through the neutral only to where it joins line B neutral, and the power from line B (opposite phase) HOT only to where it joins line A neutral. The Two HOTS are basically together at 240 volts when the lines are using equal power. They 'power' is still only 20 amps, but at 240V? Only when one line is using more power does the neutral to the breaker box come into play.
 As far as the power cares..At least this is my minimal understanding of it as a blind fool can know, basically.
And generally the power in wall was done at least back in 1960 ish. When the building was built. I bet today the code would not allow it. Back then??