DR device! What is it and what is its application?

The theme of this article is the DR breaker, but do you know what DR? Let’s show the meaning of the DR breaker and explain what the DR is for and how to choose a DR breaker, come on guys!

What is the DR switch?

Also known as Residual Differential Switch (IDR), Residual Differential (DR) is a mandatory protective device in all electrical installations, but despite being mandatory, most electrical installations in Brazil do not have a DR.

The installation of a DR should be something very simple and common, but as most installations do not follow what the standard says, there are few professionals who really understand the subject and with this, the number of electricians with doubts is increasing bigger.

Know the applications of the DR device and understand why the use of this component is mandatory.

What is the application of DR?

To facilitate understanding, the residual differential device (DR) as we have already said is a protection device . It is used inside electrical installations working as an automatic switch, having the function of de-energizing the circuit whenever there is a current leak that is higher than this DR is able to detect.

The residual differential switch also helps to save money, since when it realizes this leakage of electric current and disarms, it will indirectly contribute by avoiding the increase in the electric bill, precisely by not allowing the unnecessary expenses caused by the leakage of electric current.

DR device: User safety

The mandatory requirement of DR is to protect users against electric shock, because the moment it detects the leakage of current into the person’s body, it disarms immediately. Therefore, with protection occurring in this way, the serious consequences of electric shocks are minimized considerably.

The need to use the DR protection device is even greater in environments that are considered to be at higher risk, that is, where electric shocks can happen with greater intensity due to local conditions such as, where there are electric showers, electric bathtubs, others electronic devices and the presence of water ..

DR device: How does it work?

There are several ratings of DR, but it will always function as a switch that trips when a certain leakage current that is specified in the DR is reached. To better understand this, follow this example: When it is a DR with a current of 30mA, it will only trip if the difference between the current at the terminals is equal to or greater than this 30mA.

This way it is guaranteed that the user does not take a shock with a current greater than 30mA, precisely because the DR device will disarm. It is necessary to inform that the DR does take time to disarm, but this time between the moment it detected the leak and the trip is very fast, avoiding the major damages in cases of current leakage.

In this video below you can check out a complete class on IDR, DR and DDR. See the differences between them and how important it is to make the correct sizing. That’s right folks, there’s no use using any DR device, the right thing is to do the calculations to guarantee both the operation and the ideal protection.


People do not imagine that accidents can happen to them and therefore, many do not pay due attention to prevention and protection. When it comes to electrical accidents, the person almost never has a second chance. So, do not wait to happen to take a lesson, take precautions and use all the protection components following the indications of the norms, mainly in environments with water!