All about short circuits
Suddenly the power in the home goes off. The fuses blow in the meter cupboard and it is impossible to switch the residual current device back on. The conclusion is quickly drawn that a short circuit has occurred in the home. This is not without danger, because in practice a short circuit can cause a fire. It is then important to find out which appliance caused the short circuit. For safety reasons, the electricity in the home is automatically switched off when there is a short circuit. The power supply in the home is then temporarily shut down. In some cases not the whole home is without power, but only part of it. When the kettle is without power for a while, this is no disaster. But what if a freezer, fridge or central heating boiler ends up without power?
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01What is a short circuit?
A short circuit is an electrical phenomenon in which the resistance is so small that a very high current starts to flow through the electricity cables. In practice the resistance value can become this small by connecting the two poles of a socket directly to each other, without an electrical device with a resistance value being connected to it. A short circuit can also arise when the electrical device is still connected, but a connection is nevertheless created between the two poles. The current always chooses the easiest path and will then mainly flow through the new connection without resistance.
When the resistance becomes very low, the electric current strength increases sharply. This is due to the so-called Ohm's law, which states that the current through the electrical conductor is directly proportional to the potential difference between the ends. Mathematically this is expressed as U = I.R, where U equals the voltage (“the potential difference”), I the current and R the electrical resistance value. Expressed differently, I = U/R. And that is where the shoe pinches: when the resistance value becomes very small and U remains constant, I will take on enormously large values. A very high current will then flow through the conductor.
Risks of a short circuit
When the current rises high due to a short circuit, this entails various risks. These risks follow directly from the Joule effect. This Joule effect represents the amount of heat generated when an electric current flows through the resistance. Here the amount of heat (W) equals I².R.t, where t equals the time in seconds. Even though the resistance value R becomes very small when both poles are connected to each other, a very large amount of heat is still generated due to the square of the very high current. The greatest danger is that a short circuit can cause a fire.
Short circuit and fire
The consequence of the above is that the heat rises so high that the wires can melt. In addition, an electric arc can arise that is comparable to the arc in electric welding. As a result a short circuit can cause a fire.
With a broken plug, people often think they can fix the problem themselves by temporarily taping it together. We advise against doing this, because the electricity cables can become much hotter in the event of a short circuit. As a result the tape can melt or even catch fire. In that way a short circuit can cause a fire. We therefore recommend rather replacing the appliance with a new one, or at least having the plug replaced by someone who knows what they are doing.
Short circuits and exploding batteries
Short circuits can also occur in batteries. This is the case when the positive and negative poles come into direct contact with each other, without a resistance value between them. Here too the current and ultimately the heat will rise high. With a short circuit in batteries the battery will become very hot and may start to leak. In addition, this can even result in an explosion. The impact is smaller if the battery has only limited capacity left. In any case, after a short circuit the battery will no longer work and will have lost (almost) all of its capacity. Exploding batteries are very dangerous because of the chemicals that are used. In addition, due to the heat build-up it is also possible here that the short circuit causes a fire.
Other consequences of a short circuit
That a short circuit has consequences is beyond dispute. Besides the fact that a short circuit can cause a fire, there are quite a few other adverse consequences. For example, a short circuit has consequences for the fuse box and a circuit ends up without power. It is of course not nice if the freezer gets no power for quite a while and food ends up in the bin. In addition, a short circuit can also damage appliances. The heat is, for example, great enough to make the copper tracks on a circuit board evaporate. In such a case the appliance is ready for the scrapheap. Precisely because a short circuit has consequences you would rather not experience, it is important to take precautions. Below we therefore list a number of tips.
Detecting a short circuit
Because a short circuit involves great risks and a short circuit can cause a fire, the electrical installation of a home is always protected. In the past this was done with a fuse or plug fuse. In this way a weak link was built in that would be hit first in the event of a short circuit. In a controlled environment containing an extinguishing agent, the wire could then burn through. Once the fuse or plug fuse was broken, it had to be replaced. Appliances can also be protected in this way. Multimeters, for example, often contain such a fuse.
Nowadays so-called circuit breakers are used in homes. These circuit breakers do not break when a short circuit occurs, but they do switch off the power. A circuit breaker works differently and uses magnetic protection, but the aim is just the same as with a fuse. In any case detecting a short circuit is not difficult in either case: go to the fuse box and if a fuse has given out, you are probably dealing with a short circuit. Detecting the source of the short circuit is somewhat more complex and you can read more about that below.
Incidentally, a short circuit is by no means always unintended or undesirable. For example, a train causes a short circuit between two rails, causing a safety relay to drop out. Because they detect and register the short circuit, people in the control tower always know where the train is.
02Preventing a short circuit: handy tips
Preventing a short circuit is better than detecting and fixing a short circuit. That is why we have listed a number of tips to prevent short circuits in the future.
Check that the electrical cables are properly insulated. This can reduce the risk of a short circuit. Do not use appliances whose cables are exposed or damaged.
Hold the plug when you pull it out of the socket. Never hold the cable itself!
Only use equipment that bears a CE marking, a KEMA-keur or the German VDE mark.
Always read the instructions for use before getting started with an electrical appliance. Also always keep the instructions for use.
Avoid laying cords under doors or floor coverings. This can make them wear faster and cause a short circuit. In the worst case these cables can even overheat and cause a house fire.
Cables are not meant for hanging things on.
Never use nails or staples to fasten a cable.
Never use more than one extension cord between the appliance and the socket. Stacking sockets increases the chance of cables becoming jammed. This can cause a fire. When too many appliances are connected, the cord can overheat.
Always unroll an extension cord completely, for example on a cable reel.
In damp environments, pay close attention to where you roll out the cables, because electrical wiring must not get wet. When the wiring corrodes, the chance of a short circuit is very high.
If batteries are stored loose in a box, there is always a risk of a short circuit. This is especially the case with button cells, where the poles are close together. Here it is advisable to stick them onto a strip of tape.
Ensure good maintenance of appliances such as fridges, freezers and dryers.
Replace extremely old appliances, especially if they have moving parts. The cabling simply becomes more brittle and then the risk of a short circuit increases.
What is a short circuit? Solution, Consequences & How to prevent it?
All about short circuits ✅. How does a short circuit arise? What are the dangers of a short circuit? Tips for short circuits on EnergieAanbieding.nl.
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