I have no idea what size amp is in my fuse holder. I ordered a wire harness from Sonar Pros an upgraded to the one that came with the appropriate Garmin plugs already soldered to the harness and it already had the correct size fuse for my specific set up. I can go look at it and report back. My boat is easily accessible so it would not be a problem if you need me too, just ask.Originally Posted by mlamb7
FYI... yes you can put too large of an fuse in there. To the best of my memory the correct size fuse should blow at anything above 125% of the normal load. For example if you have a 12V circuit with a 12 amp load you would want a 15 amp fuse...12X125%=15. For a 12V circuit with 20 amps you would want a 25 amp fuse 20X125%=25. If you put a 40 amp fuse on either of my examples its going to get extremely hot or possibly do damage to the device before it blows the fuse. Hence why you want to use the proper rated size fuse for the load you will have...Another FYI is wire size is also important for various reasons. It's been a several years since my electrical 101 class so my memory or math may not be correct on the numbers but I can assure you there is such a thing as too big of a fuse and proper wire size is important...hence why I went the route of a custom wire harness from a professional builder. I could have built it myself for less money but these guys do a lot better job than me at soldering and crimping, plus they know the correct wire size and fuse size so I just let them build the harness and all I had to do was simply install it...now there's nothing wrong with doing your own wiring. Just ensure your using the right size components and have water resistant connections.
After reading my reply a day later I just thought of something...I think the 125% rating is for when the device first starts up and it actually trips at 85% if the amperage is constant. Again its been a while since my electrical class so research your correct fuse size. It should be in the Garmin owners manual.
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