Domestic Consumer Units | Fuse Boards | Screwfix Huge range of domestic consumer units at Screwfix. Protect homes from system overloads which can cause electrical fires. Fuse boards to meet legislative requirements from top trade brands. Free delivery available or click and collect in as little as a minute from hundreds of stores nationwide. Fuse Box and Consumer Unit Replacement and Costs A fuse box and a consumer unit serve the same purpose. They distribute electricity in your house through multiple circuits and instantly turn the power off whenever a power overload occurs on one of the circuits, which is commonly known as “tripping”. When “tripping” occurs, a consumer unit will switch the power off using the circuit breaker linked to the overloaded circuit.