I replaced two separate switches in my kitchen with one dual switch. The top switch controls a light, the bottom a garbage disposal. These are on seperate breakers on my main box. I have four wires coming in: One Black (Hot) with multiple wires into one wire; one white (Hot?), two black (neutral).
I tested this by using a voltage meter and found that the multiple black with either neutral registered 120v and the white with either neutral black registered 120v.
I seem to have everything wired correctly: When the appropriate circuit breaker is off, the corresponding switch will not work. Here are my questions:

1) If the white wire IS hot, shouldn't it have be marked black? If yes, I can do this.
2) When I turn off the lower switch(disposal), a tiny blue flash appears within the switch. Is this normal, or have I done something wrong? (I did remove the the break off fin)

Thanks
Jeff

 

A black neutral? Is this a really, really old house? Black wires as neutrals haven't be legal in a long, long time. I suggest you spend $15 on a tick tester to help figure out what is what. I'm not sure I believe all of your analysis.

1. If the tick tester confirms that a white wire is hot, then yes, mark it with black marker.

2. Some spark happens with all switches. It may be more pronounced with a large load like a disposal. Since the spark is "tiny", I'd ignore it.

 

Yes you should mark the white wire black, it a fairly new code, so it probably wasnt marked when it was originally put in.
The tiny blue flash is comming from the large load your disposal is pulling when it first kicks on. As an electrician, I would replace it with a new switch, just to make sure its not the contacts in that switch, but then again if John would ignore it, your probably alright, hes pretty sharp.