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As with anything electrical always think SAFETY FIRST, death and serious injury can occur if you do not know what you are doing. If in any doubt then consult an approved and trained electrician before attempting any work yourself.

OK, now the safety aspect is covered lets talk about the fuse box.
All electrical installations must protect both equipment and more importantly, people, from damage and injury, the fuse box is the first line of defence.

The fuse box you find in your home is there to protect you against short circuits and overloads to your electrical systems.

In very basic terms a short circuit is where a fault has developed that can allow electricity to flow though an object and may allow live voltages to be accessed by a person. A simple example is if a metal switch on your wall were to develop a fault that meant if you touched the switch you would get an electric shock.

An overload can also be caused by faulty equipment in the home or by external factors such as a surge from the local grid.

We have all had a fuse box "trip" on us at one time or another where for no apparent reason all the lights suddenly go out and we have to hunt for the flashlight to identify the main circuit breaker in the box. This is normally the largest switch on the fuse box and can be reset manually by simply pushing it back to its ON position. The most common cause for this if no work is being done in your house is a surge from the local grid. At this stage it is safe and easy to resolve, however if the switch keeps tripping then more investigative work is required.

First off, turn off all the other trip switches on the fuse box, this will ensure that if there is a problem within your house it will be isolated from the Main Circuit Breaker (MCB). Now try and turn on the MCB and if it trips you know that the problem is more than you can handle and the electric complany should be called.

If the MCB does not trip then the supply to your house is good and you can now work out if anything inside your building is causing the problem.
One at a time with a few seconds pause between each, try and reset the circuits that you earlier turned off. My preference would be to start with the lights, as this helps you to see what you are doing !

If at some point you find a trip switch that will not reset then investigation into what is on that circuit needs to be done. Hopefully you will have some form of information as to what each fuse is connected to, otherwise it could be a long time before you finally find the correct ring circuit.

Sometimes you will get all the way through the whole fuse box without a single trip, this could be down to a surge from one of your electrical items (e.g a fridge compressor starting), unfortunately when this happens it can be very difficult to diagnose until it "dies" completely.

If you have the older style fuse box then you will be looking at fuse wire or fuse capsules that will "blow" if a fault is found. This means turning off the MCB to isolate your house from the incoming supply BEFORE attempting to replace the fuse. Always remember to replace the correct rating of fuse or wire and never place a higher rating in place, this is one of the singularly most dangerous practices to attempt. The best that you can hope for is a broken piece of equipment, the worst is fire and death! You have been warned.

Again, if in doubt, DO NOT TOUCH any electrical installation if not completely confident with your ability and knowledge, it is far safer to pick a phone and call someone than pick up a screwdriver and experiment with electricity.

Learn more about this author, Ian Yates.
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