Question PSU making sound when PC is turned off

[Argroth]

Hey i just found that my Corsair RMx 750 is making "buzz" sound whne the PC is off.

Is it normal?

That's a new PSU i bought like month or two ago.

 

[Lutfij]

Does the noise go away when you connect the PC/PSU to another wall outlet? Do you have a surge protector between the PSU and the wall outlet? Best list your specs like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:

 

[Argroth]

Oh sorry, wrong forum. Yes i do have surge protector.

My rig:
Intel Core i7-9700k
MSI RTX 2080 super gaming x trio
Gigabyte Aorus Z390 master
Corsair RMx 750W
G.Skill Ripjaws V - 16GB (2x8), 3200MHz
SilentiumPC Armis AR7X TG RGB
Windows 10 64bit

I'll try another wall outlet when i'm back home from work

 

[Argroth]

Forgot to mention that when i switched on/off on the back off the PSU i saw flash inside.