That there are "short circuits" that they are dangerous and, as a rule, because of them electricity is disconnected, even school students know. But what process is and why it conducts to such consequences, even people with the higher education can not always explain.
You are far from laws of Ohm and hardly imagine process of passing of charged particles on a chain, your profession is not connected at all with electricity and which in the way does not concern laws of physics, however the words "short circuit" for the unknown reason known since childhood, instantly give the reaction connected with danger to life and health.
School course of physics
Any consumer of electric current eating from the socket whether it be a teapot, the iron or the TV, represents the certain source of resistance which is at the same time transforming electric energy of a chain which it closes at inclusion of a plug in the socket, in thermal or mechanical. If for any reason the chain becomes isolated without participation of above-mentioned devices, there will be a condition for effect of the so-called law of Joule Lenz according to which on the site of a chain on which there was a short circuit instantly there will be an emission of thermal energy of huge size considerably exceeding force of the current proceeding on the damaged site. This thermal energy also leads to mechanical and thermal destructions of the discussed site.
In addition, damages of electric conducting, the most used device can be serious reasons for emergence of short circuit.
Will lead the precautionary measures which are not taken in time, negligence, misuse of devices to short circuit.
Phase and zero
The most reasonable security measure from short circuit is use of the special safety locks manufactured of fusible materials which in a case emergence of earlier discussed thermal and electric conditions in a chain will instantly break off contacts.
From the physical point of view short circuit call connection of points of a chain with different potentials, namely a certain phase and zero.
Besides danger which is concealed in itself by short circuit this phenomenon has also practical applications, being used for carrying out electric welding which heating temperature time reaches more than five thousand degrees Celsius. It is possible to operate so destructive energy and it is necessary, it is worth selecting only correctly special insulating materials which will correspond in all respects to indications of electric current, to perform visual inspections, not to break technology of operation of devices at all, to cut off power conducting in case of conducting open works, it is correct to apply protection or safety locks.