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Discussion Starter · #1 ·
So I have random problems with melting my fused power distribution blocks. Like once a year my fused distribution block melts and I need to buy a new one. Its weird it goes so long being fine then one day gets hot enough to melt. Happened like 3-4 times now in that many years on the same install. I have zero gauge running to the trunk where it splits in the fused d block with 4 gauge going to my amps. I then have my 4 gauge grounds ran to the same ring terminal and grounded to the body under the seatbelt bracket under the back seat.

Anyway, someone told me my ground is bad and I needed to move it. I've searched online and seen plenty of people say the seatbelt bolt is not a good spot. I can see that in a car with a frame, but in a unibody car shouldn't that be a good thick piece of metal to ground to? If not, where is the best spot to ground to? I've always grounded to the rear seatbelt bolts in all my cars and never had a problem until this car. Its a 2005 mitsubishi eclipse if it matters.
 

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Find a good spot where you can get the metal surgically clean on both sides…not even a hint of paint or primer. Then sand your ground lug to make sure there’s nothing on it and use a star washer between the lug and grounding point…they really dig in when you tighten the bolt…and use a bolt, not screws. I use fender washers on the bottom side with a lock nut on the bolt then I seal the bottom side with silicone to prevent rust and contamination. The one I did in my new car yesterday used a 10mm bolt.
 

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^ Solid advice, far better than a seat belt bolt.

What type of distro is it, and what type of fuses does it take? Is it sufficient for the total load from your amps?

Also, are your 0 and 4 gauge connected to it securely? A loose cable will generate heat, enought to melt plastic when your amps are pulling high current.
 

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So your fuse holder is melting....how would a bad ground cause that?
If the fuse holder is melting and the fuse is not blowing and the power wire insulation is not deformed at all around the fuse holder the most likely thing here is heat from the engine or a loose fuse causing an intermediate connection causing heat at those connection points which then tries to dissipate into the fuse holder. Since the fuse holder is not a heat sink it melts.
 

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Discussion Starter · #6 ·
I have had multiple fused distribution blocks melt and they have been multiple different kinds. I had a orion, a couple different styles from knukonceptz, and i currently just installed a no-name one I bought off Amazon.

I know the connections have been rock solid, I'm anal about wiring. Lol All connections are completed with wire ferrules. They give a good crimp on the wire and the set screws lock on to them good and don't back out. Plus it just makes everything look nice and neat.. I don't think loose connections at the distribution block are my problem. Especially considering how many times I've gone over everything and switched things out.

And the distribution block is in the trunk, so its safe from heat and weather. I have a main 250amp fuse by the battery under hood but that has never popped on me. Its always the fuses in the trunk blowing. The wire has never melted at all or anything, its always just the distribution block. The plastic that the fuse holders mount to will melt eventually and the 2 power wires will end up touching and popping fuses.

I just don't get it why it keeps happening.
 

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Check resistance. Welds on unibodies are what hold up the electrical path. That's why a seat bolt on one part of the car can be good but not on another.

Dielectric grease is great for corrosion proofing sanded grounding spots.

Resistance/crappy fuses (don't blow when they are rated to) are the only things I can think of that would melt a fuse holder not on the exhaust manifold!
 

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If you are not crimping the ferrule on a 4 awg wire and are using the set screw to crimp the connection that is your problem.
A set screw in a ****ty ni name amazon fuse block are not strong enough and only make a connection on part of the wire.
Either crimp the ferrule with a ferrule crimp tool or just use bare wire.
 

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Discussion Starter · #9 ·
I did just use the set screws to crimp the ferrules but they are on there solid and not coming off so I'm not exactly sure how that could be a problem. I put the ferrules on once and they have stayed after switching multiple times because after the first time cranking the set screws down I couldn't get them off without cutting them. Its basically crimped, just not with a actual tool.
 

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I did just use the set screws to crimp the ferrules but they are on there solid and not coming off so I'm not exactly sure how that could be a problem. I put the ferrules on once and they have stayed after switching multiple times because after the first time cranking the set screws down I couldn't get them off without cutting them. Its basically crimped, just not with a actual tool.
Ok.
 

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Get a multimeter and check the resistance of where you want to ground to.
 

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FYI--a set screw type ferrule might be secure, but is NOT necessarily equivalent to a properly crimped ferrule in terms of electrical conductivity.

The reason is simple ... a proper crimp physically compresses all of the individual soft copper wires into full contact with each and every wire next to it, and also into the confines of the ferrule, until the ferrule body effectively becomes the entire contact surface.

With a set screw type wire ferrule, the set screw mostly penetrates between the wires (actually pushing some of them apart even while still pressing some of them together, but ONLY at the screw contact point.
In short, while the set screw DOES effectively secure the wire to the ferrule, it does NOT have the conductivity advantages of a true crimp wire ferrule.

Please know that I am NOT saying that using set screw ferrules is the source of your ground problem, or even that your set screw ferrules are not making a good connection...

That said, you DO indicate that the fuse holder overheating has followed your install through different iterations and fuse holder brands. And you also say that the the set screw ferrules are original to your install. And it also sounds like you have more then a couple of those screw ferrules being used as a ground.

Since overheating fuse holders ARE a sign of potentially poor ground connections SOMEWHERE...I suggest actually finally checking those set screw ferrules for positive contact INSIDE the ferrule and NOT just by physically tugging on it.

Alternatively, and as long as you have at least 1" of slack on each end of each wire, you could simply cut the screw ferrule off, strip the wire back the additional inch, and replace it with a proper crimp ferrule.

Of course you also need a proper and clean frame grounding point as well.

just my .02
 

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^^^^

FYI--

There are several good reasons that the aviation and space industry ONLY use crimp ferrules and not set screw ferrules or even solder joints. 🤣

One of them simply involves the ease of repeatability in making a reliable connection by using a decent crimper tool and a well trained worker.

That said, probably the most important reason those industries use crimp connections is to insure vibration resistance over time...which is something that neither your car, nor a set screw ferrule, is immune to!!!

I am just bringing this up because it just might explain the intermittence of your overheating connection problem.
 

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Discussion Starter · #14 ·
Why would crimping it with a proper crimper be so important in my application? I'm literally just using a ferrule as a sleeve to keep the wire nice and neat so I don't have any little wires poking out anywhere. Thats it. The ferrule is just a super thin piece of metal. Is there really a difference between smashing bare wire down under a set screw vs doing the same thing with a ferrule around it?
 

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Discussion Starter · #15 ·
I'm thinking I might cut them off and put new ones on. I'll just drill a little hole in the ferrule for the set screws to go through. That way I can use them to keep everything nice and clean like I have it but it will let the set screws compress the wire like the ferrule isn't there.
 

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how much current do you run through your set-up? sounds like you would be melting if you are generating a lot of heat, the only time you would generate a lot of heat is if you have high current + high resistance together. and the heat will generate where the high resistance is.

The plastic that the fuse holders mount to will melt eventually and the 2 power wires will end up touching and popping fuses.
what do you mean by this? if power wires touch each other it shouldn't matter, do you mean the power wires touch a ground point or touch some ground wires.....?

Resistance/crappy fuses (don't blow when they are rated to) are the only things I can think of that would melt a fuse holder not on the exhaust manifold!
This above sounds likely, can you try brand new fuses next time? Also, just try no ferrules as a test.

Also, also, pics will speak a thousand words in this situation.
 

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Discussion Starter · #17 ·
how much current do you run through your set-up? sounds like you would be melting if you are generating a lot of heat, the only time you would generate a lot of heat is if you have high current + high resistance together. and the heat will generate where the high resistance is.
Not a ton. I haven't measured with a multimeter on a test tone or anything but the amps can only pull like 120 amps together at most.

what do you mean by this? if power wires touch each other it shouldn't matter, do you mean the power wires touch a ground point or touch some ground wires.....?
I'm not sure exactly. This is how I find the problem though, my sub amp will cut out first and when I got to check fuses the holder will be melted and the 2 separate power connections will be touching. I always figure once they touch it tries to pull more than the individual fuses are rated for and they pop. But I'm not sure exactly. I have used holders from knukonceptz, stinger, orion, and am currently using a no name one off Amazon. Funny thing is the no name one has lasted the longest so far.

This above sounds likely, can you try brand new fuses next time? Also, just try no ferrules as a test.

Also, also, pics will speak a thousand words in this situation.
I've used brand new fuses every time. I use mini anl fuses. I attached a picture of the fuse holder. Not sure if you want to see anything else.
 

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Discussion Starter · #18 ·
Not sure why you guys hate the ferrules so much. Lol

Just watched this video and this guy actually suggests not crimping ferrules for power wires. This was my reasoning too and why I just let the set screws do the crimping.

YouTube
 

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in terms of troubleshooting, i think the ferrules add extra complexity.... so that could theoretically add extra issues/parts failing.
i actually used them first tine in my last set-up, they worked well for me. i personally don't dislike them or anything.

do you have any pics of the burnt/damaged fuse block? your stuff looks nice..... man this is a brain scratcher. what about pics of the fuse block where it is actually mounted?
 

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if you tug pretty hard on the black/brown wires.... they don't pull out, right?
could the set-screws be backing out a little and getting loose over the course of 1-yr or whatever? causing intermittent connection?
 
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