Differential automatic: the importance of the right to choose, a connection

powerful protective force from the harmful effect of electric current on the human body is a machine differential.It combines the functions of circuit breaker and residual current devices (RCD).The effect of this machine is aimed at protecting the wiring from overload, short circuit, and to protect people from electricity when it enters the area of ​​high voltage and touching the electrical equipment elements.

How to choose the desired differential automatic

Currently, preference is given according to the device with a high capacity off (3000 A must for these terminal devices, 6000 A must for the group) and protected against damage to the neutral conductor.If the room has several lines of electricity consumption, it is best for each of them separately to implement the differential connection of the machine.Previously should find the internal voltage, calculate the total power of household appliances and lighting, which will be connected to this line, and then to buy the specified device.

main points selection machine

  1. basic (nominal) voltage of the device must correspond to the indicator, which is designed this network.This is an important condition.For a single-phase network is not less than 230 B, and in case of a three-phase - within 400 B.
  2. display maximum (nominal) current differential machine should not be greater than that of the corresponding circuit.This will prevent network congestion, overheating conductive and insulating parts.

Procedure for self-disconnecting device specified

  • Inspect the machine and determine the cause of tripping (overload the network, a short circuit, leakage).
  • Push the housing the reset button after the cause of tripping.

principle of the device

consider in detail how the differential works machine wiring diagram which is the same as in the RCD.The principle of the device consists of a comparison of electric currents passing through the phase «L» and «N» (zero).In this case, it is an important factor.If the system is operating normally, that is, electrical appliances and wiring are not violated, the figures are identical.If you have problems with access to current data values ​​are significantly different from each other.Automatic differential will determine the incompatibilities and the leakage indicator exceeds the nominal power off automatically.This important property of the device.If there is a protective trip should be to deal with the cause, and then turn on the device.


Differential machine must have one-piece body (no dents, cracks and other defects), mandatory labeling on it that corresponds to the desired setting, and the mechanism that is responsible for turning on and off of the device must be in working order.