This article answers the question in which cases should an RCD be installed in a distribution board, and in which a DIF machine should be installed. And are these devices necessary in principle? Maybe we can make do with old Soviet traffic jams?
What are the main differences between these externally similar protection devices?
The RCD will only protect a person from electric shock when touching a phase wire. And in the composition DIF machine is not only RCD, but also a circuit breaker of a certain current rating. In addition to human protection, WPPT will protect short circuit wiring. Externally, these switches can be distinguished by their markings - before the number of the rated operating current in the DIF machine there is a Latin letter B or C. The RCD is indicated only by numbers.
In what cases is it necessary to install an RCD?
RCDs are most often installed on a separate line, where the risk of electric shock is quite high. For example, on a washing machine or boiler. RCD always supplemented by installing a circuit breaker. It is possible to install one RCD on a group of machines with the same current values. For example, there is one RCD for room sockets, and another for light switches.It should be noted that the total rating of the circuit breakers should not be higher than the rating of the RCD. For example, in one of the electrical wiring groups there are three 10 A circuit breakers installed, then the rating of the RCD must be no lower than 32 A. In this case, the input circuit breaker cannot be more than 25 A. From the above it follows that one RCD should not be installed on all lines in the distribution board desirable. The lines must be divided into each with its own RCD.
In what cases is it necessary to install a DIF machine?
We said above that a DIF machine is a ready-made design of an RCD and a circuit breaker with certain characteristics. Its characteristics can no longer be changed. Therefore, it is recommended to install the DIF machine on a separate line to power one device, which cannot be connected to the group due to the totality of its characteristics. For example, an oven or electric stove. Never install DIF automatic to groups of circuit breakers. An RCD is more suitable for this. And you should not install a DIF machine instead of an input one, especially when a meter is connected after it.
And now, ATTENTION. This is especially important to know
Neither the DIF machine nor the RCD will perform their protective functions in a situation where a person simultaneously touches the neutral and phase wires. Simply put, if someone (such cases especially often happen with children because of their curiosity) puts their fingers into the socket, or, even worse, it will be the fingers of different hands. These protective devices will consider this situation normal, like connecting any load to the line - a TV, a fan. The person will be electrocuted and this could be fatal.
And as a bonus
Do not be fooled by the promises of unscrupulous electricians who promise to make a super-distribution board for an additional fee, installing a lot of expensive, imported protection devices in it. You do not have a control panel for the launch of intercontinental missiles, but a simple city apartment. Balance necessity and sufficiency.
One more thing
This applies not only RCD and DIF devices, which we are talking about. Typically, all complex multifunctional devices are of lower quality than simple devices designed for one specific purpose. The DIF automatic is precisely a complex combined device. However, other factors should be taken into account here - the manufacturer of the product, the country of manufacture, etc.
