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The fusible link is just a piece of wire- It was cheap, quick, and simple, but inaccurate in the protection it provided. AND I hear others say "just use a wire 4GU smaller"- great idea but the fusible link should be covered with a flame retardant material- as the wire glows red hot before it breaks and could make a mess of your harness and/or whatever is next to it.
I replaced all mine...in my 71 and 73
If you look at newer cars- they are using fuses.
I'd use a "Maxi" type fuse- 50A - or a circuit breaker-if everything is stock.
You want it as close to the '"source" as possible- in your case it's the starter lug.
Remember- if the alternator shorts out- it quits working.
If the battery shorts out- well that's a different story!!!
I would think the reason for a fused link, and not a fuse is the location. Exposure to all of the elements, including ice and road salt would have caused deterioration of a blade fuse and the socket. By putting a fuse inside a non flammable wire, they avoided that.
^^ yeah, that's a concern for sure... if I use the fuse holder idea, I'll relocate it up to the firewall area where it would be easily accessible.
The fusable links I found yesterday at Orielly's were nothing more than a piece of crappy wire and a few terminal ends... I'll look for something better before I cut everything loose on the harness.
I wouldn't use a standard fuse holder or a 30A fuse, that's all too small and won't be reliable. If the car is stock, then something like a 80A MAXI fuse would be more appropriate.
A fusible link could be compared to a fuse with a very long time-delay. So, a fast acting fuse isn't a great idea. A fuse with time delay would be more appropriate.
A fusible link properly terminated and using double wall heatshrink to seal the terminations will be way more reliable than a fuse holder.
I would just use fusible links also. Not that I disagree with Richard454, just what I would do if I had an issue with a fusible link. They are a reliable simple piece of wire (that's about all they really are) and they do a satisfactory protection job.
There is considerable difference between a fusible link and a fuse/circuit breaker. The fusible link is placed where the SHOULD be NO reason for it to blow...unless a component failure or "cockpit problem" causes a dead short. It is merely a 'fail-safe' item for an electric line where no problem SHOULD occur.
I would ALWAYS replace a fusible link with another fusible link, whether purchased or DIY fabricated. BUT it should be made properly: the wire should be two AWG sizes smaller than the regular wire; the insulation on that wire should be non-flammable; and the termination points where the fusible link joins with the regular wire should have non-flammable lugs. The whole purpose for a fusible link is to prevent any possibility of a wiring fire WHEN the fusible link blows.
I cover my junction points with a blob of JB Weld [stick] epoxy. That will prevent any heat from transmitting from the fusible link to the regular wiring.
Yes, a fusible link should only burn if there is a major wiring issue shorting out the main wiring feed. You're going to have to fix that wire issue before the car can be driven again. So, I wouldn't even put a fusible links failure on the list of items to be concerned about. There are many, many other things that are more likely to fail.
Still, one time I did have a fusible link corrode and fail because the previous owner poked through the insulation in the middle of it with a test light. So, I patched it together on the side of the road and drove it home. Poking through the insulation in the middle of the link doesn't even make any troubleshooting sense, but some clown still did it...
Working on cleaning up the wiring on my '73 today and discovered the fusable link in the starter harness is damaged.
Any reason not to replace it with a standard heavy duty fuse holder and blade style 30 amp fuse?
Is the fusable link supposed to offer "slow blow" protection as opposed to the conventional quick blow fuse I'm considering?
Your thoughts please.
mardyn
I'd use an auto reset circuit breaker and get one that's about 20% above my max amp rating before putting one of those parts store fusible links in...just saying
Just sayin'....that putting a circuit breaker in a major power line ADDS risk because of the potential for power 'spikes' causing it to trip while the car is in use and/or the risk of failure of the circuit breaker, itself.
It's rare that a user is able to "out-engineer" what was done by GM on these cars.
Yes, I considered that option as well....particularly as I have some hew ones sitting on the shelf in the shop.
My thoughts at this moment are NOT to try and reinvent the wheel (as I usually do) and just go back with the replacement F/link in the stock location.
The original link is still intact, but it appears that the insulation was saturated with oil and deteriorated over the years. Somebody wrapped it with electrical tape at some point but I'm going to replace it with new parts once I get back on it.
Regarding a higher level of weather protection for an in-line fuse, there are weather resistant holders out there for that purpose. I wouldn't use them in replacement of a fuseable link, but in other locations in the engine compartment, they might work well. Keep in mind, they are not totally waterproof, they are weather resistant.
As what 'Richard454' clearly stated in POST #2. "Everybody is gonna have an opinion on this-"
Richard I have to say is one of the most unique customizers here on the forum and his knowledge is exceptional...SO..in his custom build he will know every square inch of what he has built and will have the ability to repair any problem.
I am not saying that there are not others out there....I just have not seen what they are doing to that level of excellence.
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For me...I have customers who would not replace a fuse if it blew or even knwo where to look for it.
So...I put the cars electrical system back as it was designed. Kinda a liability issue also. No need for me to 're-invent the wheel'..here also.
On the custom builds I do..I will use MAXi-fuses and whatever I feel is appropriate to make sure the electrical system is going to be problem free....even if it is installing fusible links.
And for whatever it is worth.....when I am installing a fusible link a the correct length and gauge size for the wire I am attaching it to..I ALWAYS try to make sure that the fusible link is not wrapped into the harness bundle and it is left out of it so IF it burns...it is not going to possibly damage anything....even though I know that the covering of the fusible link is designed not to melt and separate....BUT..I take no chances. And I also make sure that the section of the fusible link that is exposed is possibly NOT going to be able to touch any metal IF it burns.
And for what it is worth...I have looked in many of my 1997 and newer Corvette shop manuals and I have not found in any wiring diagram as of yet where GM uses a fusible link. NOT saying there is not one...but I have not found one or seen it in wiring schematic as of yet.
If you buy a Painless or similar harness it has a maxi fuse.
When I did my 71 I ran a 6 gauge wire from the stud on the alternator to the horn relay with a 40 amp maxi fuse. All the power for the rest of the car comes thru the horn relay? I carry an extra fuse. No issues so far. No AC or anything other than the SPAL fan that's a heavy draw.
I am running a LS swap with a Camaro alternator so much higher output from a stock 71 alternator. Amp gauge is gone replaced with a voltmeter.
Before folks get excited that their C3s are in danger, please keep in mind who's in Ron Francis target market. From his article -"fusible links are no longer an accepted way to wire a performance vehicle" (aka - heavily modified) .
Street rodders have used Ron Francis products for many, many years. Street rodders don't like wires showing and try to conceal them from view. You can't have a fusible link concealed into a harness, it has to be out in the open as in our C3's. Look at Lectric Limiteds replacement harness to the starter, it has the stock fusible link, totally free of any convoluted plastic covering. If this was dangerous, why would a company run the risk? Just don't tuck that fusible link up with anything else.
Ron Francis has some excellent products and I highly recommend them for somebody upgrading/rewiring their wiring. Check his web site for the maxi fuse holders that go up to 80 amps (I think). Just my .02 cents
Well, as has been said many times, "Ignorance is bliss!". A properly designed fusible link WILL NOT light-off. It's insulation is non-flammable and it has non-flammable terminals.
With that said, it is not the only way to protect a power line. Fuses (rather than circuit breakers) are doable. But, they are more costly than fusible links. And, logically, if you are trying to 'protect' a line that SHOULD never have a reason to over-current (unless there is a major component failure which causes a dead short), why not use the least expensive item that is "appropriate" for the job.
Now, to a point made that the fusible link should never be 'wrapped' into a wire bundle... that is absolutely correct! The fusible link WILL create heat; but on its own (important), it will not light.
If the wiring system of the vehicle NEEDS to be tidied-up to where there should be NO loose, hanging wires, then the fusible link is NOT appropriate. That line should then be fused...BECAUSE of aesthetics. And, many custom vehicles are all about aesthetics. No problem here on that score.
My whole purpose in responding to this thread was to voice concerns about replacing fusible links with "inappropriate" materials. Most folks THINK they know what a fusible link is. But, no, they only know what one looks like...generally, they don't know HOW they are made or designed...or why. When dealing with power carrying wiring, ignorance is NOT bliss. It's an accident waiting to happen.
The company i worked for back in the 70s made replace fusible links ( sold many many thousands ) for the aftermarket . sold them for less then a dollar ( if i remember right they were 40 to 60 cents ) but at the dealer or shop they would get 40 to 60 dollars to diagnose and replace one because few people new what they were .
Fusable Link replacement?
