Fusible link

[00fxd]

I'm thinking of installing a 12 guage [no 10 guage available] fusible link between the alt [internally regulated] and the starter [10 guage], and, my car takes power from the alt to the horn relay [10 guage] so I'm planning on installing one there too. Is this a good idea? I'm wondering about a couple of things. 1st, how many amps does it take to fuse the 12 guage? Should I be using a 10 guage? I was planning on useing the new maxi fuse 50 amp when I stumbled on this idea.
In the package with the fusible link came a caution: "when replacing fusible link, the wire gauge should be 4 gauges smaller than the existing wire circuit; eg, 14 guage system, use 18 guage fusible link wire". I'm not sure about this. Any opinions?

 

[IH2LOSE]

I am not sure of the gauges and the amperage they carry,
What are you trying to accomplish have you had problems prior or are you just trying to be safe against fires?

I was in a car stereo place last week and they had some excellent resetable circut breakers meant for the stereo amplefiiers in all amp sizes.I am also sure they would be able to send you in the correct direction.I have a caddy with a elaborate stereo system and the breakers are all over the places.Good to see you being safe

 

[00fxd]

Thanks for your thoughts IH2LOSE. Suprised no one else has any experience or training that they can share with the properties of fusible link.

 

[bradfordsvettes]

fusable links were used for years by the general and others you are correct on the 4 sizes smaller use. that is how the link works it is also a special wire and if i am not mistaking it needs to be less than 4 inches long to work correctly hope this helps it is basicly an inline fuse for main legs steve

 

[00fxd]

Thanks Steve. What circuit's were they used in at that time? If I were to use a 14 guage fusible link [a 4" length of actual fusible link wire] in the 10 guage line from alt to starter would it carry the load?

 

[bradfordsvettes]

that is what the book says i put one on the 61 because they never had one of any kind,kind of scary if you think of it no wonder so many had fires never mind the glass fuel bowls . that is the formula that i use at work for repairs.and they do work if something is shorted. never had one come back. it is just the same as a fuse only it is the main fuse it may have more than 1 some were at the horn relay too hope that helps steve :TALK

 

[00fxd]

I went over to the local auto parts store today and got the lowdown. The back of the Napa/Beldon wire and cable catalogue has a complete FAQ about fusible link. Belive it or not, Here is a quote from that page. "the conductor in fusible link is the same as regular primary wire [copper]. IT IS NOT A LOW MELTING POINT COPPER CONDUCTOR. It IS approximatley four wire guage sizes smaller than the circuit wire leading up to it.". It goes on to say that because it is smaller wire it will become much hotter in a dead short than the lead in wire. When it hits 1000 degrees, it will separate and break the circuit. The ddifference in fusible link wire and standard conductor is the insulation. It is designed to hold the heat in so the conductor will melt quicker. It also suggests that all terminations be heatshrink insulated to help hold the heat in.
I'm still not 100% comfortable with this method. I figure if there's a 10 guage wire, it's there for a reason and installing a lighter guage has gotta cause some resistance and maybe even some heat at full load. Just thinkin' out load, gotta stop that.....

 

[bradfordsvettes]

what you read is 100% correct that is why you need fusable link wire don't be afraid it works like a charm ever look at the link in the old glass car or home fuses it is pretty wimpy in comparison to the wire it feeds but that is the saftey net go for it napa sells the kits with heat shrink connectors good luck steve

 

[magicv8]

After all the advice, I'll give you the WARNING - using fuses, breakers, or fusable links may hasten the demise of the "ammeter" (actually a galvanometer) in the instrument cluster. Be sure to put a 1 amp or less fuse in the ammeter line to protect the gauge - in case one of your inserted fuses, links, or breakers interupt the galvanometer shunt.

 

[bradfordsvettes]

that is good advise i lost an amp meter in the 69 when i had a short didn't even give that a thought thanks Steve

 

[bradfordsvettes]

but with out the link you would be in real s--t if you had a short and loose the meter anyways steve

 

[magicv8]

I am not saying don't use fuses/breakers/links. I am saying - while you are working on the harness, you should insert a 1 amp fuse in the meter line.

 

[Mac]

If you're looking to retain originality, the fusible link is the way to go but if functionality and safety is more important, I would look at either a circuit breaker, as 1h2lose suggested or relays with fuses. Let's face it- all of the automotive manufacturers went away from fusible links for a reason- safety. Why take a chance of a fire when better technology is available?

 

[00fxd]

I was thinking of using it as an extra margine of safety in addition to the regular fuse box. We've all seen older cars with the main harness all melted to h*ll for one reason or another. Since I don't plan on changing my main harness right away it was considered for a little more protection. I had planned on using maxi fuse when I started thinking about using the fusible link and found that there was a lot about it that I didn't know. I will also be installing a 1 amp fuse in the amp guage feed.

 

[bradfordsvettes]

put the link in that is what they are for they are easier to use in tight places although a fuse or breaker will work . I have seen breakers fail in the closed position and burn up wiring. the link or fuse is the only way to go when it blows it has done its job steve