What is the root cause of DB box got humming sound ?

It also makes the current in house unstable once in a while.
Ie : the light blink for a second or whole unit got no electricity for a few second to a minute.

probably a loose connection. pls get any experienced electrician checked.

probably a loose connection. pls get any experienced electrician checked.

symptoms of loose connection. get it checked asap, before it turns to fire.

Fire going to come out of your DB. For now use as little powerful appliances as you can, until you get this checked out

Damn .. sound dangerous .. where lose connection ? In the db ?

Should check power consuming appliances and their corresponding fuse in your DB (Air conditioning / Kitchen electric burners / Water heaters / Dryers etc).

Check if there's any smoke smell coming from your DB or any fuse burnt.

Get a certified electrician check ASAP.

Something is definitely wrong.

you better get some certified electrician fast to check out.