We are already going to be using a transformer beforehand.
Here's the story.
We are making a light dimmer, but we are attempting to have it controled via remote control. We have an RC network that feeds into a Diac, but because the Digital Pot (10k max) we are using only takes max +/- 5V, we have to use a voltage divider with a 470k ohm resistor if we want to apply the 240V mains. Because we can't do this, we have to reduce the mains via a transformer, but then the problem becomes the breakover voltage of the Diac, which is about 35V. Which is why we need to amplify the output of the Digital Pot.