Now connect the Neutral wire “N” (Blue color) to the input “N” terminal of RCD. The output “N” terminal of RCD should be connected to the Neutral busbar terminal in the consumer unit. More recently RCBO’s have since come onto the scene. These are essentially a combination of an MCB and RCD so provide additional safety levels. Also they resolve the nuisance tripping issue highlighted in subsequent versions of the Wiring Regulations.

How many consumer units do you need? You’ll only need one consumer unit for a home in most cases. However, there are some scenarios where you may need to fit a second consumer unit. For example, when adding electrical circuits to an extension in an existing building. The current consumer unit can only provide a certain amount of wattage. If the new circuit is going to exceed that wattage, then a second consumer unit will need to be installed. You may also want to install a second consumer unit if you’re powering an outbuilding, such as a garage or shed. The author will not be liable for any losses, injuries, or damages from the display or use of this information or if you try any circuit in wrong format. So please! Be careful because it’s all about electricity and electricity is too dangerous. The 18th edition consumer unit requirements supersede 17th edition wiring regulations. So, if you haven’t installed a new consumer unit for a while, here’s a summary of the changes: One very interesting point to note is that as of the issuing of the second edition of the BS7671 18th Edition Wiring Regulations, it introduces section 531.3.2 concerning unwanted tripping and how to minimise nuisance tripping in the home. Essentially, if an EICR (Electrical Installation Condition Report) is carried out on such a setup and it is found that everything is working as it should be then all should be well, as long as there are no outside or zoned circuits that require an RCD.The first type is the single load consumer unit. This is where the incoming mains power is first taken through a double pole isolation switch, which then in turn feeds a live bus bar that supplies each MCB on the board.

In pretty much every other configuration they are a required feature for each and every individual circuit. Similarly, connect the Phase or Live wire “L” (Brown color) to the live terminal of RCD. The output Live terminal of RCD should be bonded to other MCB’s via a common copper busbar segment terminal. Finally, connect the incoming earth/ground wire in Green with Yellow Stripe color (from the main earthing system) to the earth busbar terminal in the garage consumer unit. One of the most important jobs your electrician will (or should) do before starting such a job is to first ensure they test all of the existing circuits in the property to make sure they function correctly and have no issues.Firstly, MCB’s are clipped on to the DIN rail and positioned as required for the number of circuits that are being run from the consumer unit. Each MCB is installed by clipping it onto a DIN bar and the "teeth" of the bus bar are inserted into the base of each MCB. This carries the live current into the MCB and the cable that supplies the given circuit are connected to the top section. Today, many consumer units that are installed will feature at least 1 RCD, sometimes 2 as this is really considered to be the “belt and braces” approach. If not, then most likely today, each circuit will use an RCBO.