This week on Sundays With Sully we are talking Protection in particular Circuit and fuse protection. Check it out and as always be sure to hit that like tag and share button!
Can you explain in a bit more detail what you mean when you said the fuses are to protect the wire and not a device. Where does the wire come from that goes to the fuse block? And then it goes to the device after? As in MFD or USB charger, or ignition?
Great question and one that we get asked often - per ABYC standards, we run wire for the install based on the load (i.e. how much power is this item going to draw) So lets say we have a Bilge pump that has a nominal amp draw of 12 amps. And lets say the wire run from the battery to the pump is 5'. We have to measure the round trip of that so that's 10'. We use ABYC standards for amp draw and circuit length that tells us we should have a 14 gauge wire. I say all of that to get to this point - if this bilge pump ends up with a rotor lock (pump is trying to run but can spin due to something stuck in the pump) the amp draw will ramp up. Because the amp draw ramp up if there was no fuse we would quickly be drawing more amperage than the wire is capable of handling. This would create heat and eventually let the smoke out of the wire and potentially start a fire. Now if we put a fuse near the battery (source of power) and have this same scenario as soon as that rotor lock event happens and the amps spike the fuse will blow and the wire will be saved as designed. Conversely if you put in a 30 amp fuse into this scenario, it would take longer to blow (or possibly not blow at all) in the mean time the wire will heat up from the increased amperage that is above what it is designed to handle. Again worse case scenario here is letting out the smoke and a fire starting all while not tripping the fuse because it was over sized and it didn't reach its max amp limit to blow. Hopefully you have made it this far in the response and that answered your question!
@@navtronicsmarinegroup haha. Yes I made it that far. Not to long at all when it’s a great explanation (that did need some backup as well). Thanks and have a great weekend.
