If you want the right answer ... ask the right question!
Ultimately, there is ALWAYS a voltage potential in any neutral wire or neutral buss. Even if your meter reads "0".
You'll get a measurement greater than zero, representing the voltage drop over the path you are measuring. Thus, a bad connection somewhere will lead to a higher reading.
Secondly ... and this is the tricky part to understand .... "0" volts read does NOT mean that electricity isn't flowing like mad through the buss. Just open that neutral, and you;ll see quite a spark ... and probably damage something. This is because all that power delivered by the 'hot' wires is trying to get back to where it was made ... and the neutral buss is part of that path home.