A burnt car is a sad sight. How to protect yourself from fire, says reader Alexander GERASIMOV.

After the accident, it is possible, if not to restore the car, then at least sell the remaining whole parts. After the fire, there remains only a black skeleton, suitable, perhaps, for scrapping. The fact that a car filled with gasoline and oil burns to the ground is not surprising. However, the cause of most fires is not the ignition of the fuel at all, but the “short circuit in the electrical wiring” that has snapped up in the criminal-fire chronicle. Alas, the quality of electrical circuits in our cars is often below all criticism.

Protecting yourself from such a misfortune is not difficult: you just need to turn off the battery when you go home. But the trouble is, we are in a hurry, brothers, we are in a hurry … And to say it is a pleasure: having arrived home, in decent clothes, climb under the hood with a wrench, unscrew some terminal! However, the recipe has long been known - the switch "mass". On the shelves you can find many designs, expensive and cheap, with remote electrical control and a primitive contact bolt. But the installation of any of them creates a problem with the operation of electric clocks, alarms, and the self-installation of some radio tape recorders “to the code”. How to solve this problem?

There are two main options. The first one is a compromise and simple one: additionally connect the negative terminal of the battery with the case, bypassing the ground switch through a low-current fuse. Its operating current should be sufficient for the alarm to function (if it does not have an autonomous power supply), but when a powerful consumer is turned on or a short circuit in the wiring, the fuse simply burns, thereby disconnecting the entire system. Since you must at least once turn on the starter, forgetting about the “mass” switch, keep spare fuses at hand. It is more convenient to use a push-button thermal fuse of repeated action, but it will not save the radio from automatic blocking, if such a function is embedded in it.

The second option is more convenient, although much more time-consuming. Its essence lies in laying an additional "negative" wire to the consumer bodies that are specially isolated from the "mass", which should not be de-energized in your absence. The easiest way to do this is for the clock and radio, but you will have to tinker with the alarm system: as a rule, it uses a lot of contact sensors connected by one of the terminals to the "mass" of the car. It will be necessary to install additional insulated door and engine compartment switches and pull the “negative” wire to each of them.

But what if the alarm system has an exit to the central lock, headlights or a regular sound signal? After all, they do not work with the mass off. Additional relays will help here, which will bypass the mass switch for the duration of the operation of these devices. The connection diagram of such relays is shown in the figure.

Consulting whether your particular alarm will work with such a switch on and whether all its functions are preserved will not hurt: complicated systems may not be designed for this.