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Ammonit News 2018-07

Protecting sensitive measurement equipment against lightning strike and voltage flashover. You can reduce the potential risks just by considering some important rules. Read more in the July issue of our Ammonit News.


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Dear Reader,

It is summer time and currently quite a few colleagues enjoy their holidays. What is your feeling about the summer in this year? Do you have also the impression that we have to cope with more and more extreme weather phenomena? Longer dry periods, heavy rain with flooding and more thunder storms with lightning.

Hence, we want to introduce measures that can protect your sensitive electrical equipment installed on the met mast since lightning can lead to a total breakdown of your measurement system.




According to IEC 61400-12-1:2017 lightning protection is not mandatory for met masts. Although the IEC standard describes the installation of a lightning finial and the top-mounted anemometer. Just by considering some simple measures you can protect your sensitive measurement equipment. For sure the protective measures are cost-intensive but the total breakdown of your system with loosing valuable measurement data is much more expensive.


Damages due to lightning and overvoltage should not be underestimated. Thus we recommend installing the lightning finial with proper grounding as described in IEC 61400-12-1:2017 and shown in the photos of this news bulletin.

In order to reduce the risk of voltage flashover and magnetic coupling, signal cables should physically be separated from the grounding cable.

The Ammonit steel cabinet, which hosts data logger, communication and power supply unit, can be considered as Faraday cage protecting equipment against electric currents such as lightning strikes and electrostatic discharges, since the enclosing cage conducts current around the outside of the enclosed space and none passes through the interior.

Inside the Ammonit steel cabinet further measures help to protect the valuable measurement equipment.

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According to the Single Entry Point principle all incoming and outgoing connections to the data logger and the sensors are centrally conducted into the steel cabinet. Inside the steel cabinet Overvoltage Protection (OVP) modules protect the interior against overvoltage from outside by conducting the energy of lightning to earth.

OVP modules prevent lightning and overvoltage from disrupting low voltage supplies to the measuring system equipment. OVP modules protect data and signal lines and power cables. OVP modules are installed in the Ammonit steel cabinet instead of unprotected cable clamps.

We offer several types of overvoltage protection modules, differing in their number of pins and their voltage levels. Although the installation of overvoltage protection is not mandatory, it is highly recommended. Overvoltage protection is especially recommended for freestanding measuring stations or when aircraft obstacle lights are employed.


There are a lot more options available how you can protect your measurement system. In our news bulletin we introduce the most common methods. If you are interested in further details, we are happy to discuss with you. We are also curious to hear about your overvoltage protection methods.

Special thanks to our US partner Double-k for providing the met mast pictures of this news bulletin.

Did you miss one of our news updates? Have a look on our website. All previous bulletins are listed online:

For further information about our products and solutions, refer to our website or contact our sales team via This email address is being protected from spambots. You need JavaScript enabled to view it. .

Kind regards,
Ammonit Measurement GmbH

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E: dt[at]
T: 49-30-6003188-0

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Ammonit Measurement GmbH
Wrangelstrasse 100
10997 Berlin

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T: +49-30-6003188-0

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