Buzz in the breaker box

Just recently when I am in the basement I can hear a buzz from the breaker box. Please let me know what are some things that cause noise to come out of an electrical panel. I have circuit breakers, not fuses.
Thanks,
Tim
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I've noticed this on my breaker box. It was breakers rattling, not sitting very tightly on the posts.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.