0805 resistor across the 230VAC post bridge DC bus?

[cupoftea]

Hi,
We have been sent in a customers failed SMPS development, and asked to get it working.
It’s a 220W 230VAC offline PFC’d supply.
The PFC uses an 0805 across the post rectifier bus as attached.
In my book, 0805 is 150V max….but they say that since the DC bus is regularly going to zero, its allright. Do you concur with their declaration?
(my apologies "MOUT" pin should read "IAC" pin in the attached)

 

[scopeprobe]

If peak voltage is above the peak voltage of the part then they're likely riding their luck. The resisters arn't the same value either so the is likely that 383k has most of the 300+ Volts on it

 

[FvM]

Resistors with higher voltage rating are available, e.g. https://www.mouser.de/pdfdocs/HVC-2.PDF

For standard 0805 resistors, a 150V working voltage spec can be expected. It's not o.k. to apply rectified mains voltage.

--- Updated Nov 24, 2022 ---

Another HV resistor series https://www.vishay.com/docs/28881/tnpve3.pdf
The datasheet counts DC or ACrms as working voltage.

 

[pjmelect]

A single resistor will fail in short order, the normal solution to this problem is to put three or more equal value resistors in series.