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Fusible links VS inline fuses

Kern Dog

Life is full of turns. Build your car to handle.
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Hello there,
In 2015 I eliminated the ammeter in my Charger and 75 Power Wagon. I also put 10g wires from the alternator to the starter relay using a fusible link at the end of each. The interior of each were powered by another 10g wire ran through a drilled hole in the bulkhead. Those also had fusible links.
Today I did a similar thing to my Brother in Law's 72 Duster.
The alternator charge wire still uses a fusible link but when I looking around for some stuff, I found THESE:

a wire.jpg

So for the Duster, I soldered in one and used a 30 amp fuse.

a wire 2.jpg
a wire 3.jpg


Now, on the Charger....I still have the fusible link. I am tempted to step back and change the fusible link here to the inline fuse, also with a 30 amp fuse.
I'd like opinions on this. To me, it seems that having the inline fuse is better because if it blows, the repairs might be easier and may not require soldering. I'm just thinking of the scenario of being away from home with minimal tools....
The red wire in the middle is the interior power wire.

a wire 1.jpg
 
Kern, here's a good article...
https://www.onallcylinders.com/2017/11/17/fusible-links-go/

And from the article...

"Fuses are typically used on circuits with a relatively low current draw, measured in amperes, ranging from one amp to 40 amps.

But certain automotive components require momentary higher peak current levels depending, so a fixed-rating fuse may not be ideal. "

So I guess if it is going to see high amp draw a fusible link can take the spike without popping whereas the fuse will just pop.
 
30 amps isn't enough I would use at least a 50 if not a 60 amp maxi-fuse.... Better yet replace the 10 ga wire with a 6 or 8 ga wire & use a 80 amp slo-blow type fuse.... Slo-blow fuses allow brief spikes but prolonged over amperage pops the fuse..

https://www.alliedelec.com/product/littelfuse/0298080-zxeh/70519426/View attachment 847358


Oh, just to add to that.... Maxi-fuse vs standard ATC fuse...
Screen Shot 2019-10-08 at 9.44.41 PM.png


And they sell fuse holders for the Maxi-fuse similar to the ATC fuse holder you posted..
 
The normal "ATO" type fuses will blow in about 1 second at there rated current.
A Slow-Blow "Maxi" type fuse takes around 2 Minutes to blow at rated current, much more like a fusible link that can withstand short periods where the current is above the rating.
 
30 amps isn't enough I would use at least a 50 if not a 60 amp maxi-fuse.... Better yet replace the 10 ga wire with a 6 or 8 ga wire & use a 80 amp slo-blow type fuse.... Slo-blow fuses allow brief spikes but prolonged over amperage pops the fuse..

I took a few pointers from the MAD Electrical site in 2015 when I dumped the ammeter and swapped in the gauges in the Charger. The car has been running this way for 4 years, 45 years before it with the stock wiring. I just thought that the inline fuse idea seemed like an easier fix if there was a problem. I could leave it as is if the inline fuse idea is an inferior concept.
I do see the logic of the fusible link being able to withstand a power spike better. Still, It seems that this inline fuse is a step up from the stock 12g wires ran through corroded terminals twice.
I am new to this but it seems that 50 or 60 amps is waaaay more than the demands of the gauges and other interior components. Is there such a thing as a 50 amp mini fuse?
I'm not against replacing the inline fuse with a fusible link. I just thought I found a better idea. So far, I have been able to do several electrical changes in both cars without having to spend much. I had a bunch of odds and ends here from a parts stash I bought years ago. It is great to have all I need right here.
 
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I took a few pointers from the MAD Electrical site in 2015 when I dumped the ammeter and swapped in the gauges in the Charger. The car has been running this way for 4 years, 45 years before it with the stock wiring. I just thought that the inline fuse idea seemed like an easier fix if there was a problem. I could leave it as is if the inline fuse idea is an inferior concept.
I do see the logic of the fusible link being able to withstand a power spike better. Still, It seems that this inline fuse is a step up from the stock 12g wires ran through corroded terminals twice.

4 ft of 10 ga is capable of a constant 85 amps @ 12v

I'm assuming your are running an alternator capable of more than 30ish amps

I like the idea of the slo-blow fuse design vs a fusible link...

They are available in many amp ratings, I based the 80 amp selection off an assumption you have more electrical loads than original & the thought that the future may add additional loads...
 
Christ....I thought I was doing good by improving on the factory setup.
With the Charger, I added the auxiliary fuse box ran through the relay to supply power for the aftermarket stuff in the car.
Still not enough?? :eek:
 
Here's were that gets funny.... That fuse holder? 14Ga leads? It's rated at 20 amps max...
Okay...Easy enough to unwrap the tape and swap in something better.
 
Christ....I thought I was doing good by improving on the factory setup.
With the Charger, I added the auxiliary fuse box ran through the relay to supply power for the aftermarket stuff in the car.
Still not enough?? :eek:

Yes, it is, for what you improved... It's really a matter of whether you want to live with good enough or make it as good as you know how...

Think of it along the same lines as doing a few electrical upgrades to your 1970 vintage house.... Now the inspector wants everything brought up to code...

I avoid letting the inspector look around to much...:lol: But I do see the value in some of the upgrades...
 
Yeah....
I enjoy tinkering with the car. I think I'll leave the Charger as is for now and if I intend to add more demand later, I'll upgrade then.
As for the Brother in Law's car, thank you for the advice. Given my limited knowledge, I based my moves on what seemed to make sense. I had no idea of how much current the wires are capable of flowing.
 
I believe a slow blow fuse is a GREAT idea but there is no need to go crazy with fuse ratings...

Using basic power calculations (P=I X E formula) Power = I (current - in this case a 30 amp fuse rating) times E (voltage). At 12 volts that is 360 watts and at 13.8 volts that is 414 watts. I've never heard of an alternator capable of either of those outputs. I agree that a massive short to ground in the load side might produce such a draw but the likely hood is extremely unlikely.

Fusing a circuit beyond the conductor capability is not a good idea unless you want to replace all the wires because they melted due to over current draw. The wire is what a fuse is really protecting....
 
Most of the aftermarket wiring companies supply a 50 amp maxi breaker with their kits.
 
Using basic power calculations (P=I X E formula) Power = I (current - in this case a 30 amp fuse rating) times E (voltage). At 12 volts that is 360 watts and at 13.8 volts that is 414 watts. I've never heard of an alternator capable of either of those outputs.

Screen Shot 2019-10-09 at 8.55.39 AM.png
 
If a 30 amp fuse does the job, why would you put a bigger one in? If the fuse becomes a current restrictor it will blow, and then you can upgrade. In your case the charging current does not flow through that 30 amp fuse.
 
YUP, I have to admit my rational was flawed..... Problem is, I knew better. Should have waited for that third cup of coffee to take effect...
 
The higher amp fuse does go in the charge circuit, thats why it's a high amp fuse, It's capacity has to be based on the output of the alternator... The more loads you add the more you need to look at the charging system...

Every circuit needs to be protected & the loads should be considered when selecting the fuse or circuit breaker...

Personally I don't care for the Mad Electrical bypass, I understand his reasons for doing what he does & it's fine for a old pickup but I don't see fit as suited for the restored or modified muscle car...

I prefer to use the bulkhead connector strictly for low amp loads & I want to be able to unplug all the connectors not drill out sockets & run wires through them...

I feed the power for larger loads like my power windows & power top through a bulkhead battery connection & use lots of relays...

If you look my car over not much is visible, most folks assume it is stock... But for some reason the windows work great, the headlights are brighter, the A/C & fan work better than most...
 
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