The Stovebolt Site Forums The Shop Area The Electrical Bay fusible link

Anyone know the amp rating of a 14 guage fusible link? Once upon a time I had a chart,,but that CRS,,& I can't seem to find one online. Brian

Brian,

I have never used a fusible link, so the research to answer this question was a learning tool for me. The bible says a 14 ga fusible link will protect 10 ga wire which has a ampacity of 25 amps....does this sound correct.

Stuart

I guess that sounds about right,,I suppose that is enough. Originally the lead in wire to the fusebox on 64s was a 10 guage non-fused(!) wire. I just thought a link would be good. I might look for one those newfangled Maxipad fuses instead. Brian

Stuart has the right approach.

All I know about fusible links are posted Here

Don't use a fuse! Fusible links are much more safe and secure.

This should get some hair up...I think links are a pain in the butt,if you use them and one burns out there you are out in the country with the link junk,,I use breakers and spade fuses you get same protection and donot have to rewire...doc

But *if* one burns out, which is a very rare occurance, it surely means that you have an *extremely* serious problem that requires more than a quick fix.

I'm with "doc41". I believe that having current proctection is very important but hiding that protection under insulation and such doesn't get it with me. I've read that new car manufactures are moving away from them. I trust my ride to the same wiring techniques that protect my house and most likly yours. The fuse is to protect the wire downstream from it. The wire upstream will handle the the current necessary to "pop" the fuse and other feeder circuits. A fuse/breaker are easy to troubleshoot and replace if necessary. This "argument" extends to the redundant relay issue with cooling fans and such. If one relay of two in parallel feeding a cooling fan goes out there is no way to trouble shoot it short of removal and testing. I don't run two cooling fan relays, two brake light switches, two relays for the headlights, etc. We're not flying the space shuttle here.

You know, it is simple enough to carry a spare fusible link in the glove box, just like a fuse or two, and with a little planning, to set up your wiring so that access to the link is not a PITA. As for the multiple relays for the cooling fan, the reasoning is not for ease of troubleshooting, but to prevent a single relay failure from rendering your engine toast. Small aircraft have had redundancy for decades. To each his own, but I've invested far too much money, sweat and time into my truck to pass up adding a $4 relay. Once the reasoning was explained to me, it seemed a no-brainer.

I dunno, GM used nothing-I just thought a fusible link would be some protection. My 79 Ford has them, in 28 yrs now never a trouble w/them. I planned on adding the cooling fan wiring separate from the rest of the truck, & the A/C fan has its own power supply also. Brian

If you look at some of the latest new vehicles they have illiminated the fuseable links and instead installed a seperate fuse panel in the engine compartment for heavier wiring such as lights, air cond,electric fan,starter etc and any other circuit above 30 amp with fuses and circuit breakers. Even the battery has a fuse to protect the whole system.If you've got the room and don't want to keep it original I think that might the easier way to go.The only problem I've ever seen with that system is when your boosting the battery you have to make sure you get the cables correct the first time otherwise you blow the fuse. Bob T

If you ask me, the newer vehicles have illiminated a lot of things ... like illiminating any possibility for owners to fix *anything* themselves.

I don't drive a '54 Chevy pickup for nothin'!

So can anyone tell us why a link is better protection than a spade fuse????doc

I guess you didn't read the info from the link I posted?


Here's an excerpt for you:

"... fusible links never fry unless there's a very serious problem that needs your immediate attention (like a major power wire grounding against metal!); a problem that a circuit breaker or in-line fuse could mask well enough to have you finding your car in flames. Fusible links are the safest way to protect your electrical system and keep your vehicle from an electrical fire.

An in-line fuse on a 30-amp electric fan circuit (as I discovered) won't last very long. When that fan kicks in, it's more likely to pull 60 amps (initially) than 30 and after a dozen times or so that in-line fuse will give up it's ghost and burn out -- it's a gradual breakdown that occurs.

Just like an in-line fuse, a 30-amp circuit breaker is also subject to wearing out and eventually frying ... it just takes longer.

A fusible link will never wear out. It will only burn out protecting your vehicle from bursting into flames due to a serious short that needs your immediate attention -- nothing else is gonna do that for you. You can see many fusible links in older cars, still doing their job after 20 years or more."

Another point of view...Alan, I did read your link. I'm impressed by your passion for the link over fuses or breakers. As to your arguements for links due to operational cycles and the over current on start up of certain electricial devices found in our rides....well I not totally convinced. If you read the fine print on such things as fuses and breakers you will notice they are heat activated as are links. They have engineered into them a delay for that higher than normal start up current. Generally 125% of their maximum current capacity for X period of time. As I'm sure you know, anytime you power up a circuit that is not purely resistive you will get an inductive or capacitive kick. Ever notice how the lights dim in some cases when you turn your air compressor or A/C on, Well, that's the kick. Your shop fuses or breakers hold that and keep right on ticking. I not against links. I will have several on my ride when it is finished but I also still believe in fuses and breakers.

The same laws of physics apply to the fusable material in an inline fuse as a fusable link. If your fuse is failing from fatigue you may be using the wrong fuse.

If you replace it with a slow-blow device you have now changed the weakest part of the system to something else, perhaps the very part the fuse was intended to protect.

I've never been a fan of fusable links, but more important is to understand why you would use one versus why you would use a simple fuse or circuit breaker. I'm pretty sure the major manufacturers used fusable links because they are cheaper to make and install than big fuses. It doesn't take much of a savings to motivate Detroit to do something cheaper.

My unsolicited opinion is that even if fusible links protect for longer than fuses without degrading, you can't look at one and know that it failed as easily as you can a fuse, and changing a fuse on a "dark and stormy night" is easier than changing a fusible link to get you home.

Same here. Certainly, I wouldn't use links for *everything* ...

Fusilbe link doing it's job.

http://www.ronfrancis.com/images/chart-file14.pdf

Well guys, I went w/a fusible link,,plenty of wire extra for future repairs if needed. GM used nothing before the fusebox, but I thought it would be a good idea(there's 10+ feet from battery to fusebox). I had a nice 40 amp breaker on old black truck, but I cannot find it, & I really couldn't figure a way to mount/wire a Maxi fuse w/o it looking ghetto. The fusible link is easy. Brian

dosen't it all come to what one wants,,,also one has to be smart enough to know there is a problem in either system..I have seen links removed and wire installed also gum wrappers around fuses and wire jumpers in place of spades so it all comes down to smarts,,,yes???doc

http://www.autoshop101.com/forms/hweb1.pdf

18ga. Fusible Link protects 14ga. or heavier wired systems
16ga. Fusible Link protects 12ga. or heavier wired systems
14ga. Fusible Link protects 10ga. or heavier wired systems
12ga. Fusible Link protects 8ga. or heavier wired systems

Notice in the table above that there is always a four number size difference between the Fusible Link wire gauge size, and the size of wire going out to the rest of the circuit. (And with wire gauge sizes, the larger number is for a smaller diameter–as with shotgun barrels, the 20 gauge bore diameter is smaller than the 12 gauge bore diameter.)