What Wattage rating for lamp limiter?

[Nick]

It occurred to me that a domestic dimmer switch might fit the bill as they have to dissipate anything up to 100W. I know some of the modern ones use electronics to turn the power on and off though and so won't work. I need to do some research. There's no point investing more than a few quid in this exercise as it was only an idle thought to include an easy reference table in the instructable - certainly not a requirement.

All domestic dimmers use phase control to vary power - its not a voltage control like a resistive load. Forget domestic dimmers

The main way to vary voltage is to use a variac (a type of auto-transformer) - here's my REAL power controller using a variac & RCBO, MCBs, filtering and a meter: 



The schematic is here: 
  Variac Protection.pdf (Size: 40.39 KB / Downloads: 29)

The TDK RFI filter I used is really quite complex internally - needed because I didn't want the RFI from the stuff I was driving to get back into the mains...