Types of RCDs for water heaters and the reasons for the operation of protection

Knowing the ins and outs of your heating system is essential to maintaining a warm and energy-efficient home. Every home needs a water heater because they provide hot water for cleaning, cooking, and bathing. However, they have their own set of safety precautions, just like any other appliance. Residual Current Devices (RCDs) are used in situations like that.

RCDs are like the guardians of your home; they keep an eye on the electricity flowing to your water heater at all times. They act as an essential safety precaution, shielding your belongings from any electrical risks. However, not every RCD is made equally. There are actually a number of varieties, each with special features and uses.

The RCCB (Residual Current Circuit Breaker) is one of the most popular varieties of RCDs for water heaters. In order to operate, this device compares the incoming and outgoing electrical currents continuously. It automatically cuts off the power if it senses any imbalance, reducing the chance of an electric shock or fire.

The RCBO (Residual Current Circuit Breaker with Overcurrent Protection) is another variety. This gadget provides extra protection against overcurrents in addition to keeping an eye out for electrical imbalances. This implies that it can protect your water heater from harm resulting from unexpected surges in electrical flow, like short circuits or power surges.

Why then is this protection required? Water and electricity, well, don’t go together well. There is a significant risk of electrocution when the metal casing of a water heater becomes energized due to a malfunctioning water heater or wiring. RCDs serve as a failsafe by immediately cutting off the power source.

Protective shutdown device

Water heaters are devices that use current to heat water. They are cumulative and flowing conditionally.

In the first scenario, special warm plates and pipes are used to conduct the current, heating the water. In the second scenario, where the water warms up inside the tank one at a time, a straightforward boiler and heating element are utilized. RCD: a device that guards against equipment failure and leaks of electric current for all kinds of water heaters.

What it is

An RCD, also known as a protective shutdown device, is a unique device whose primary function is to safeguard a boiler against current leaks. It occurs in a controlled, executive, launch, and differential manner.

Be aware that the RCD design in the first example includes wire windings and a ferrite ring. A direct-action, sensitive magnetic-electrical relay is used in the second scenario. A spring wire is used in the third instance, and a resistor is used in the second.

What role plays

The defense shutdown device ensures the safe and stable operation of every water heater connected to the network. The gadget is positioned close to the heater. A continuous current flows through it, supplying the system with energy. Using specialized sensors and switches, the RCD detects leaks inside the system and shuts it down completely.

It is important to note that the RCD and the automatic operate similarly in terms of principle. Even tiny electric vibrations are captured by it, which automatic machines are unable to analyze.

Note that these days, the safety of such mechanisms isn’t always guaranteed, which is why the water heater is additionally grounded. Not a difavtomat is RCD. These two systems are not the same. While the second is more widely used, the first only records leaks. Even in response to closure, overload, and other issues, he responds.

Criterias of choice

RCD mechanisms are applicable not only to boiler installations but to all other household appliances as well. One can choose from among these mechanisms based on specific criteria:

  • Power;
  • Current readings;
  • Method of installation.

Additionally, you can select an RCD based on its cost, brand, manufacturer, and user reviews. Regarding power, the RCD needs to be able to handle the same amount of energy as a water heater or other household appliance that will be connected to the equipment. The RCD power for boilers should be approximately 10 amperes, or 2-3 kilowatts of boiler power.

By current, a standard working current is used to evaluate this feature. 0.4 microamper per 1 ampere is typically taken into consideration. When it comes to installation, it is preferable to prioritize devices that are DIN-rack compatible. An alternative is to select devices in the shape of individual blocks. They can also be placed anywhere at the same time.

Which to choose

In addition to the aforementioned selection criteria, the RCD automatic has to be chosen based on the cutting current, rated current, differential current, and product current. You must connect the proper single-phase device to an apartment where the electric network is a single-phase, 220 volt system. It takes a three-phase apparatus to operate at a steady 380 volt network.

It is worthwhile to think about a few crucial points:

  • The cut -off current must exceed the current line by 25%, where it is planned to install the device.
  • The nominal electricity should be higher than what is in the cut -off. Usually it ranges from 16 to 100 amperes.
  • Differential electricity must correspond to the nominal value. The optimal limit is 30 amperes.

Note: You must also consider the kind of electric current that the product is based on when making your selection. It can have a shutter speed and be variable or constant for any kind of object.


RCDs are simple to build devices that are categorized based on multiple signs. The device classes are A, AS, B, and G. Moreover, the RCD is either electromechanical or electronic, depending on how the electric circuit is broken. Each type is then described in turn.

Class A is intended for variable or pulsating AC class alternating electrical systems. Class devices with an industrial function are included in this device. Both variable and constant straightened current can be used with them. The majority of AC class devices are found in typical apartments.

The letter S is occasionally added to the classes to denote that the device has been turned off after a while. Such designations are limited to industrial equipment because such systems are not utilized in daily life. Although they have a shorter exposure time, Class G devices are comparable to the Class of Class.

Regarding the categorization of electronic and electromechanical units, in the first instance, these are low-cost gadgets, secondhand homes, and basic systems. Expert electricians discuss how installing them is not necessary because power comes solely from the mains. The gadget will break easily if the zero wire is damaged. Furthermore, he takes a while to respond.

Electromechanical components are consumed by more than just the electrical grid. These are higher-quality, more dependable units. The sole negative aspect of their exorbitant cost.

When it comes to keeping your home warm and well-insulated, understanding the types of Residual Current Devices (RCDs) for water heaters and why they"re essential is crucial. RCDs are safety devices designed to protect you from electrical shocks and fires by quickly shutting off power if they detect a fault in the electrical system. There are different types of RCDs available, including fixed, portable, and socket outlet RCDs, each serving specific purposes. Water heaters pose particular risks due to their direct connection to water and electricity, making them potentially hazardous if not properly protected. Factors such as water conductivity and the proximity of electrical components increase the likelihood of electrical faults. Therefore, installing the right type of RCD for your water heater is essential to ensure the safety of your household and property. By understanding the importance of RCDs and selecting the appropriate type for your water heater, you can mitigate the risks associated with electrical faults and enjoy a safer living environment.

Wire with RCD

RCD on the wire is a very basic system with multiple connections possible.

Connection options

The RCD can be connected in four different ways:

  1. In a single -phase network;

  1. In a three -phase network with a confusion;

  1. Connection with a machine gun;

  1. Connection without stain to a single -phase two -wire network.

The drawings above show the corresponding scheme for each option.

It is important to remember that you must connect the automatic cutters and hold the test button in order to verify that the equipment is functioning. The equipment should continue to operate over time if everything functions as it should.

The reasons for the operation

To address the question of why the machine trips when the boiler is turned on, it is important to note that the device reacts due to various factors such as tuning, circuit connection, current load, and insulation failure. The operation is true, but it’s also false. When electrical equipment malfunctions, the task is to cut off the circuit from the voltage supply with current leaks.

Note: The RCD is activated by the equipment malfunctioning, incorrect connection, sticking the dough button, lever breakdown, leakage of current, damaged or absent grounding, and falling under the current effect.

Why is it disconnected when turning on

The water heater’s RCD may disconnect for a number of reasons, including insulation damage, leakage of current, malfunctioning of the shutdown mechanism, and incorrect placement of the device. It is important to remember that the equipment cannot be operated further if the insulation on it is damaged.

Most frequently, a broken water heater cable or the network cord itself will disable the RCD. It is crucial that the cable may be harmed internally, and a heater is frequently examined to determine the cause.

Note: It should be mentioned that this kind of thing occurs with low-quality products that are unknown in origin when the shutdown mechanism isn’t working. After multiple works, they might just be left off.


A number of well-known manufacturers are said to offer high-quality RCDs.


The Termyx RCD has terminals, a wire length of 140 centimeters, a current power of 16 amps, and it operates at 30 milliamperes. The device is made up of a metal copper tube, a dielectric, a resistance spiral, and a heating element by design.


Devices used by burning companies typically have certain features.

They lessen corrosion and electrical overspending while preventing shocks.


Regarding other manufacturers, they are made in high-quality depending on devices, protective mechanisms, and without them by ABB, Legrand, Schneider Electric, EKF, and IEK. There are also devices available that are stationary with independent models, two-pole, and four-pole.

Type of RCD Reasons for Operation of Protection
Residual Current Device (RCD) Detects leakage current caused by faults or defects, preventing electric shock.
Earth Leakage Circuit Breaker (ELCB) Responds to earth faults, safeguarding against electric shocks and fire hazards.

Selecting the appropriate Residual Current Devices (RCDs) for water heaters is essential to guaranteeing security and averting possible risks in your house. Each type of RCD—fixed or portable—has a distinct function in reducing the risk of electric shock and fire.

Installed at the main switchboard, fixed RCDs provide all-encompassing protection by keeping an eye on the circuit’s current flow. They provide continuous safety even when you’re not actively monitoring the appliance, which makes them perfect for permanent appliances like water heaters.

Conversely, portable RCDs provide ease of use and flexibility. They are ideal for temporary setups or using appliances outside because they are simple to plug into power outlets. They may not provide continuous monitoring and require manual intervention, even though they offer protection comparable to fixed RCDs.

Recognizing the significance of RCDs requires an understanding of the rationale behind protection mechanisms. Regardless of the cause—electrical malfunctions, deteriorated insulation, or unintentional immersion in water—RCDs quickly cut off power to avert flames or electrocution.

Because of their high electrical currents and continuous exposure to moisture, water heaters in particular present special risks. These devices’ flaws or malfunctions could have disastrous results if improper protection is not taken. RCDs provide a dependable first line of defense by spotting even tiny irregularities and cutting off power before accidents happen.

To sum up, purchasing the appropriate RCDs for your water heater is a crucial first step toward guaranteeing your home’s security. It is crucial to prioritize protection against electrical hazards when choosing between fixed and portable versions. Homeowners can protect their houses and loved ones by making educated decisions by knowing the causes of water heaters’ operation and the risks involved.

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