The heart of your home's electrical system is the consumer unit. From here, electricity is distributed within the house via circuit breakers, which 'trip off' to protect each circuit if it draws too much power. Understanding how the consumer unit works is vital to all types of electrical maintenance. With that in mind, here is a beginner's guide.
Care and maintenance
Be sure to turn the power off before carrying out any electrical maintenance or engineer jobs. Make the consumer unit your first stop when doing any maintenance or electrician jobs. Trip the circuit breaker that controls the circuit that you are working on, then use a voltage tester to make sure that the switch or outlet you want to work on is still live. To turn off power to the entire house, trip the main breaker, which is usually larger than the others and coloured red. If you have a fuse box, remove the main pull-out block or turn the switch to 'off'. Note: For as little as £10, you can buy a socket tester that plugs in like a plug and ensures that there is no power to the outlet which you plan to work on.
What is causing the circuit problem?
Circuit failure is usually due to one of two problems. Circuits can be overloaded, which is what happens when too many appliances are running on the same circuit. They can also be short circuited, which is when a worn live wire touches a worn neutral or another live wire, or the earth core, or any metal that is earthed. This will create a short cut for a large surge.
If you have just plugged a high-wattage appliance into a socket outlet and everything just stops working, then the circuit is probably overloaded. Try moving smaller portable appliances to another circuit that is not being used as much. Switch off or unplug the high-watt load before resetting the circuit breaker, otherwise, the breaker will probably trip again almost immediately.
A short circuit
A short circuit is the likely cause if you reset the breaker or replace the fuse and your circuit still isn't working. Do a little sleuthing to figure out what is causing the fault. First, unplug all lamps and appliances on the circuit. Then, check the plugs and flexes for damage: if a fixture, switch or outlet is discoloured or has a faint burned smell, it's the likely source of the problem. Replace the damaged flex, switch or outlet if needed.