Mine was plugged into a bad pedestal a couple years ago. My surge protector had failed and I was without that for a couple weeks and it was then the pedestal problem occurred. My transfer switch was making some sounds like popcorn popping for a few minutes until I unplugged from the pedestal. Once the pedestal was fixed the sound stopped. It was maybe four months later the transfer switch died. I ordered one on-line and replaced it and no issues since. I would suggest getting one on hand as back up just in case, or if the humming bugs you.