MathiasW
Active member
In the past 4 years, we have had 5 very close-by lightning strikes. Never a direct hit, but close enough (like 50 metres or so) to induce a lot of voltage on our electrical wiring, killing some devices every time.
When analysing the failure patterns, it became obvious that one big killer is the voltage induction on the NMEA 2000 bus. In many cases we've found that the devices went offline, but were still working fine as stand-alone device. (Like VHF radio, chart plotter, etc.). This seems to indicate that the voltage surge fried the NMEA 2000 chipset in the devices, but did not do any other harm.
Alas, whilst surge protectors for the +/- supply lines can be readily found on the internet, it is much harder to find a surge protector for the NMEA 2000 bus.
Luckily, if you know that the NMEA 2000 bus is on the physical level identical to the good old CAN bus used in automotive and, more recently, in Smart Home, your search space widens. And indeed, in smart home one can find surge protectors for the CAN bus!
So, I bought a couple and started installing them. They are rather cheap, but you do need to install one in every drop line of the bus, and it is a bit tedious as they do not come with NMEA 2000 cabling. Good news is, though, these CAN bus surge protectors are indeed compatible with the NMEA 2000 bus and all devices still work as before. That is a good start!
I will refrain, though, from making the ultimate real-life test, if I can help it...
Here is a link with more details on how I went about it: Protecting Boats Against Impacts of Lightning Strikes - SAN
Cheers, Mathias
When analysing the failure patterns, it became obvious that one big killer is the voltage induction on the NMEA 2000 bus. In many cases we've found that the devices went offline, but were still working fine as stand-alone device. (Like VHF radio, chart plotter, etc.). This seems to indicate that the voltage surge fried the NMEA 2000 chipset in the devices, but did not do any other harm.
Alas, whilst surge protectors for the +/- supply lines can be readily found on the internet, it is much harder to find a surge protector for the NMEA 2000 bus.
Luckily, if you know that the NMEA 2000 bus is on the physical level identical to the good old CAN bus used in automotive and, more recently, in Smart Home, your search space widens. And indeed, in smart home one can find surge protectors for the CAN bus!
So, I bought a couple and started installing them. They are rather cheap, but you do need to install one in every drop line of the bus, and it is a bit tedious as they do not come with NMEA 2000 cabling. Good news is, though, these CAN bus surge protectors are indeed compatible with the NMEA 2000 bus and all devices still work as before. That is a good start!
I will refrain, though, from making the ultimate real-life test, if I can help it...
Here is a link with more details on how I went about it: Protecting Boats Against Impacts of Lightning Strikes - SAN
Cheers, Mathias