Lightning Safe Switch?

[Madehn]

I am adding a chart plotter down below to aid in some route planning and as a backup. I would like to protect it from lightning strike - is there a switch out there that will work to isolate it-- i can always set it up with a separate plug in connector and leave it unplugged until/if needed but that is kind of a PIA. I would also like to connect it to my seatalk ng network but again suspect that i may have to plug and unplug it from the network? -- connecting it to the network is optional as all i really get from that is another readout of stuff i already have and i could make do with having a cable set up ready to use if i needed it. Is there a simpler way to do it? I am thinking that even unplugged, it may not be safe unless in a faraday cage. thoughts? ideas? Thanks in advance for your time.

[senormechanico]

Maybe a steel boat with a completely enclosed system, including batteries and antennas, but then it wouldn't get any signal. Nope, unless I'm missing something.


Lightning doesn't care. It just goes through whatever it takes to get to ground, another cloud or wherever the opposite polarity happens to be.

[CarlF]

Unfortunately lightening surges can easily travel through the NMEA 2000 network that goes to every piece of electronics in the boat.

A faraday cage is urban legend. The damage is done by thousand volt surges coming in any one of the many wires connected to a typical chartplotter.

A common route is for the lightening to hit a masthead vhf antenna. The surge comes down the coax and into the radio where it exits via the connected NMEA 2000 cable or the negative power wire which has no switch or fuse.

The best lightening protection is a good insurance policy

[Jammer]

Originally Posted by Madehn

I am adding a chart plotter down below to aid in some route planning and as a backup. I would like to protect it from lightning strike - is there a switch out there that will work to isolate it

Sure, there are switches. They help a little.


Best practice would be to install surge arresters on all wires going into the chartplotter. NMEA, power, GPS antenna if separate, depth transducer, ethernet cable to the radar, ,and whatever else. Cellular operators, repeater owners, and radio broadcasters, who all have 200' metal towers on mountaintops, spend the money for the good ones and believe that they are worth it. They improve the odds but are not a 100% guarantee.