intermittent buzzing in electrical panel

[kwired]

As I said, not necessarily in topic. The OP said nothing about Siemens or SMA, and the letter about Siemens failures said nothing about buzzing. We should have more info to connect the two before discussing them in the same thread.

I do agree that OP never mentioned anything about Siemens or SMA and could be totally irrelevant.

 

[gadfly56]

OP hasn't even verified the PV system is related to the problem, only that it was presumably noticed after the PV installation.

Sounds very possible that it is something that happens every time HVAC compressor starts up or something like that. PV install could have moved/disrupted something allowing it to move/vibrate more easily then before the PV install but the condition was always there. Just one possibility of many.

Without any PV installed this happens every time when my HVAC comes on. If I'm at my computer, I'll hear the buzzing at the panel as the compressor kicks in before I hear the compressor itself. Lasts about 3-4 seconds. I've put it down to inrush current.

 

[kwired]

Without any PV installed this happens every time when my HVAC comes on. If I'm at my computer, I'll hear the buzzing at the panel as the compressor kicks in before I hear the compressor itself. Lasts about 3-4 seconds. I've put it down to inrush current.

In a dwelling HVAC compressors are probably the most popular item that this happens with.

Get into non dwellings and some motors driving moderate to high inertia loads that take time to accelerate and you see this all the time. Not only buzzing at a breaker but conductors vibrating in raceway from high current during starting also. Fans with a heavy impeller/propeller - many sound horrible during motor acceleration, clears up as soon as motor gets to full speed, motor current is pretty high during that time.