So, you NEED a fuse, you NEED R1 and you NEED R2. Also, R1 and R2 MUST be surge proof, i.d. they must be able to withstand surge voltages of several thousands of volts. Also, C1 MUST be an X-cap! D1 MUST also withstand inrush and surge currents, so, you would not use a simple zener diode but a ROBUST TRANSZORB or TRANSIL, which quits an overload by a short circuit and not open circuit!!

VR1 is critical. Varistors were widely used in the passed. But overloads often resulted in an increase of leakage current and one fine day the varistor became so hot that it started to burn. Many fires occured because of an overheating varistor. Also, during surges a varistor tends to explode. So, today, when using a varistor, it NEED to be mounted with a temperature fuse and the ambient NEEDs to be protected against eventual explosion.

the bane of the high voltage amateur is (s)he get a schematic from the internet, then grab A resistor, A capacitor, A zener, A .....

unfortunately most "internet submissions" do not indicate the required "quality" of the components.

THUS, I recommend that everybody not having the required experience, let alone those that "dont have enough time to full study it and full understand", stay with circuits at 24V and below.

Erik