Distortion on the Power Line

Typically a solar power system would have very low voltage THD unloaded, but the potential for higher current THD loaded. They are measured and rated for current THD.  The output impedance should be a lot lower than the output impedance of a shared transformers unless the system is rather large. To that end, the grid should be dominant but no guarantees. It is certainly something to consider.

So let's say you correctly identify neighbor's A/C or solar panels as the culprit.  What's the point?  

three_easy_payments

So let's say you correctly identify neighbor's A/C or solar panels as the culprit. What's the point? 

The point is that that you would then know the problem is not with your service entrance or from something inside your home.

@cleeds

Don’t disagree but it seems like instead of guessing about all your neighbor’s potential sources that the best thing would be to do a process of elimination within your own home. Just seems odd all these random guesses about issues outside your home that aren’t actionable.

The best thing would be to determine if it is your own home our outside ... hence the 0 cost, quick method of figuring it out I described above. If you determine its outside your house you may have a remedy with the power company so yes it is actionable.