Fuse box makes humming sound when off-peak water heating

[fuzeboxes]

Video of issue:

Hi

I’ve noticed a humming from my fuse box when my nightly off-peak water comes on.

When I first moved in I had a similar issue, albeit louder / more high pitched. An electrician replaced the contactor at the time.

It might be worth noting that that little grey box (I think that’s the contractor?) to the left of the breaker is slightly warm.

Any ideas?

Thanks

 

[SparkyChick]

The buzzing is most likely to be the contactor and is nothing to worry about.

Contactors use electromagnets to pull a switch closed so the coils will buzz at the mains frequency.

 

[Dustydazzler]

The ‘clunk’ followed by the hummmmmm is from your contractor

 

[littlespark]

Some electricians have a stash of honey secreted in many places.

Think of Pooh Bear with an MFT

The buzzing may be the last of their special honeybees, who are nocturnal and only come awake at off peak times.

Or... as suggested, it possibly could be the contactor.