Had a ducted heat pump installed the other day.  All went well.  I opened the meter board the following day to check usage.  Closed it and it took a bit or wiggling to shut the door.

Went round did a bunch of stuff and just before I left the house noticed a cracking sound from the circuit board and then saw molten plastic dripping out of it and smoke.  Turned off the main supply and contacted the heat pump company.

They sent round an electrician who removed the bell, checked every thing, turned everything back on and it all worked.

So my question is why was this here in the first place.

Circuit board with it removed