The DIN rail relay is one of the most critical components of your electrical panel. Whether it is the residual current relay that protects your life from electric shock, a power relay that controls the water heater, or a smart Wi-Fi relay that automates your home, choosing the right one is a matter of safety and functionality.

Based on the category filters we see in the screenshot, I prepared a simple guide to help you find exactly the relay you need without getting confused by technical terminology.

1. Type

In the Type filter, you will find three main categories:

• Residual current (or Safety Relay / RCD): The most important relay in the panel. It “measures” whether there is current leakage to ground (for example, if a faulty appliance is leaking electricity or if someone touches a bare wire) and trips instantly to protect you from electric shock. It is legally required in every home.
• Power (Contactors / Relays): Used to safely control large electrical loads. For example, when you turn on the water heater from a small switch, the power relay is what takes on the high current so your switch does not burn out.
• Impulse relay: Ideal for controlling lights from many different points (e.g. in a long corridor or staircase) using simple push buttons instead of complicated two-way switches.

2. Technical Filters

To choose the right product, you need to follow your installation’s specifications:

A. Number of poles & voltage (Volt)

• 1 or 2 Poles (230V / 240V): Suitable for single-phase installations (typical homes).
• 3 or 4 Poles (400V): Suitable for three-phase installations (larger homes or commercial spaces).

B. Rated current (Amps - A)

Indicates the maximum current the relay can handle without being damaged. The most common values in a home are 25A, 40A, or 63A, and the choice must fully match the main breaker of your panel.

C. If you are choosing a residual current relay: Type & Sensitivity (mA)

If you are looking for a safety relay, pay very close attention to these two filters:

• Sensitivity (mA): For protecting people from electric shock in homes, the standard is strictly 30mA. Relays with 100mA or 300mA are mainly used for fire protection or in industrial installations.
• Relay Type (A, AC, B, F): * Type AC: The old classic type. Detects only alternating current (suitable for simple resistive loads, e.g. stove, water heater). Type A: The modern essential type. Detects alternating current as well as pulsating direct current produced by electronic devices (PCs, inverter air conditioners, washing machines). It is now preferred in modern homes.

3. Smart relays

If you want to take your panel to the next level, in the Connectivity section you will find relays with Wi-Fi, Bluetooth, or ZigBee (such as the popular Shelly models). These allow you to switch the water heater, heating, or lighting circuits directly from your phone, set schedules, and monitor consumption in real time!

Non-negotiable safety rule: Any work or change in the electrical panel involves risks and must be carried out exclusively by a licensed electrician.

Use Skroutz filters to choose the type you need (e.g. Residual current or Power), check the Amps and Poles of your installation, and choose from top and reliable manufacturers (such as Geyer, Legrand, Hager, Shelly, etc.) so you can have peace of mind!