2016 242 Limited S Audio Upgrade

[chester2008]

I purchased 4 sets of JBL M6520 6.5" Speakers and a JBL MA704 amp to run 4 speakers for now. I plan to add a 5 channel amp when they come back in stock along with a sub. The amp will power the swim deck speakers and the new helm speakers. The front and rear speakers and the tweeters will remain connected to the head unit for now.
JBL says I need a 60 amp inline fuse for MA704 amp and a 100 amp fuse for the future MA4505. I purchased an inline 200 amp fuse to cover the two amps and a small fuse block. After discussing my plan with a friend, he's got me worried that the 200 amp fuse is way too much and wont actually protect anything. I've see a lot of guys running two amps on similar fuse set ups but just wanted to get some reassurance. 0 gauge wire is running from the battery to the inline fuse and then to a distribution block, and then downsizes to 4 gauge wire to the amp. I'll post some pics as I get into more tomorrow.

 

[Mesa50]

A 200 amp fuse will allow nearly 200 amps to reach either device before it blows. You need to have the recommended fuse in front of the individual devices. The purpose of the fuse isn’t to be big enough to run multiple devices in line together, but to protect them from surges.

 

[212s]

After discussing my plan with a friend, he's got me worried that the 200 amp fuse is way too much and wont actually protect anything.

Your friend is correct. Like Mesa50 said, each device must be fused at their individual ratings for proper protection. One big fuse could allow one device to draw too much.

It's a common misconception that the fuses are there to protect the device (amp in this case), but in reality they're there to protect the boat if the device shorts. The fuse allows the device to operate at max power draw to perform properly, but if the device shorts then it will draw more current blowing the fuse. This protects the boat's wiring and batteries from a massive current draw that could overheat the wiring and ignite a fire. Same thing for a vehicle with an aftermarket stereo - the fuses protect the car from bursting into flames.

 

[chester2008]

Thanks for the help, I'll have to rewire the amps so they are better protected.