Originally Posted By: pcarter
This post was automatically imported from our archived forum.
Had an unsual humming noise coming out of Main Distribution Panel yesterday after I lightly tapped the cover. I backed away from this immediately after hearing the humming noise. There were other issues with the electrical in the home I had discovered before I went to the main. So I made a judgement call to stay out of it but my curiosity is alive and well. So the question, and pardon me if this is a dumb question? What can cause a main to emit a fairly loud humming noise after lightly tapping the panel cover?