The domestic consumer unit or fuse board, that box that sits under your stairs or in a cupboard somewhere in your home can be a daunting thing. No doubt there has been one rainy night in your life where you've found yourself crawling around under your stairs, or up a ladder with a torch, trying desperately to flick the right switch to turn the electrics back of high frequency pcb manufacturing on in your house. To understand how these units work, what goes into them and why may make those darkened fumblings a little easier, or perhaps even prevent them all together. This article is an overview of domestic UK consumer units and how they work.