Rain Sensor

In most flood alert systems, rain precipitation is an early warning for floods. A rain sensor, also sometimes referred to as a rain switch, is a sensing device activated by the presence of rainfall .Currently in our inventory we have two rain sensors. Each has its own set of uses depending on environmental conditions. They are typically located atop of a pole that is firmly secured to the ground.  Rain sensors will typically have a wire going from the sensor to the RTU.
The sensor depicted below in the event of rain, detects raindrops with the help of electrified metal contacts. It forms a conductive link between both electrodes on the sensor surface and trigger a switching signal. Once the surface has dried off, the relay drops out again after a delay.
The sensor surface is equipped with 2-stage heating. The first stage is permanently activated and prevents the sensor surface from either freezing over or thawing. The second stage is switched on when it begins to rain in order to ensure that the surface is dried quickly.
Its key features include compact size, rain and snow detection, binary signal output, internal heating mechanism (to allow operation in temperatures as low as -30°C) and IP65 Safety-Class certification.


  • Compact sensor for rain detection
  • Integrated automatic heating for ice free usage up to -30°C
  • Safety class IP65, weatherproof, mounting angle enclosed

Power supply:

Operating voltage 24V DC (15…27V DC)
Current input max 150mA (3600mW)

Data acquisition:

Measurand Rainfall
Signal Floating changeover contact element
Electrode clearance 0,7mm
Sensor face 40cm2
Turn-iff delay 5,5 min.


Alarm contact 1 floating changeover contacts
Switching capacity max. 42V AC/DC, max. 1A, max. 4,5VA


Lead LiYY 5 x 0,25mm², length 3m


Material Plastics ABS
Dimensions 75 x 54 x 18 (H x W x D)
Type/location of installation Mast or wall mounting with enclosed mounting angle

Ambient conditions:

Operating temperature -25°C … +60°C
Storage temperature -25°C … +60°C
Transportation temperature -25°C … +60°C
Rel. Humidity 5% …93% (without condensation)
Installation height up to 2000 m above sea level


Electrical isolation SELV (EN 60 950)
Class of protection I (IEC 536 / VDE 106 part 1)


Device safety acc. to EN 50 090-2-2