Fusible Link Rating (1 Viewer)
- Thread starter Sc0-
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That's not much help.
I have looked for the ratings of all three as well w/o much luck. What difference does it make if one installs a non-automatic resetting circuit breaker in lue of the fuseable link?
I have looked for the ratings of all three as well w/o much luck. What difference does it make if one installs a non-automatic resetting circuit breaker in lue of the fuseable link?
Sc0;
Here is a link to what I did for the fuse link crap that comes with most automobiles:
http://homepage.mac.com/dfmorse/BattProj2/page9.html
One of the things to conceder with fuse links is how and why they used a piece of wire in the first place.
First; a piece of wire, say 6 inches long and #12 gauge (US terminology), will handle around 100 amps for a short time and then burn up. But it will handle 40 amps all day and be mildly warm to the touch. This has to do with surge current. On our FJ80's there is an 80 amp alternator that charges the battery. When u start the cruiser, a surge current of say 200 amps is pulled from the battery, cruiser starts in less than 10 seconds, and the alternator recharges battery - this charge current flows thru the MAIN fuse link in a surge current of around 60 amps (I measured this) and then drops to around 10 amps of continuous current charging the battery. The point here is this; if u used a circuit breaker in place of the fuse link, it would have to handle surge currents very well. Not cheap and easy.
Second; fuse links of wire are cheap and easy.
There is a math formulae someplace that I look up years ago that will let u determine the metric current handling of the stock fuse links. I know from just looking at wire what it will handle and compared the size of the stock fuse links to US wire sizes.
For example, the MAIN fuse link is around a #12 gauge wire. On the schematic (EWD189U , page 48), the MAIN fuse link is listed as: FL MAIN 2.0L. The number 2.0 is the cross sectional area in mm and will determine (in metric terms) the current carrying capacity of the wire. Figuring this out was too much hassle, so #12 wire minimum is close enough for gumit work. I went to a #10 wire because I will be upgrading to a 130 amp alternator in the future.
The other fuse links (AM1 &AM2 ) are similar but, of course, smaller gauge.
Remember, don't use too small a gauge wire for the MAIN fuse link. There is a #6 white wire from the alternator output to the MAIN fuse link, which connects direct to the battery + post. U don't want the MAIN fuse link to blow; unless there is a serious short in that [MAIN] circuit. Blowing the MAIN fuse link could cause alternator damage.
OK, enough for one day..
....
Here is a link to what I did for the fuse link crap that comes with most automobiles:
http://homepage.mac.com/dfmorse/BattProj2/page9.html
One of the things to conceder with fuse links is how and why they used a piece of wire in the first place.
First; a piece of wire, say 6 inches long and #12 gauge (US terminology), will handle around 100 amps for a short time and then burn up. But it will handle 40 amps all day and be mildly warm to the touch. This has to do with surge current. On our FJ80's there is an 80 amp alternator that charges the battery. When u start the cruiser, a surge current of say 200 amps is pulled from the battery, cruiser starts in less than 10 seconds, and the alternator recharges battery - this charge current flows thru the MAIN fuse link in a surge current of around 60 amps (I measured this) and then drops to around 10 amps of continuous current charging the battery. The point here is this; if u used a circuit breaker in place of the fuse link, it would have to handle surge currents very well. Not cheap and easy.
Second; fuse links of wire are cheap and easy.
There is a math formulae someplace that I look up years ago that will let u determine the metric current handling of the stock fuse links. I know from just looking at wire what it will handle and compared the size of the stock fuse links to US wire sizes.
For example, the MAIN fuse link is around a #12 gauge wire. On the schematic (EWD189U , page 48), the MAIN fuse link is listed as: FL MAIN 2.0L. The number 2.0 is the cross sectional area in mm and will determine (in metric terms) the current carrying capacity of the wire. Figuring this out was too much hassle, so #12 wire minimum is close enough for gumit work. I went to a #10 wire because I will be upgrading to a 130 amp alternator in the future.
The other fuse links (AM1 &AM2 ) are similar but, of course, smaller gauge.
Remember, don't use too small a gauge wire for the MAIN fuse link. There is a #6 white wire from the alternator output to the MAIN fuse link, which connects direct to the battery + post. U don't want the MAIN fuse link to blow; unless there is a serious short in that [MAIN] circuit. Blowing the MAIN fuse link could cause alternator damage.
OK, enough for one day..
....
I was curious about this as well, my intention was to just buy some fusible link wire from a auto parts store. That way I could use it for other stuff.
I am running a 155 amp (tested not rated) alternator with the stock links with no problems.
Thanks trojan; will keep that in mind.
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...
Oh yes good info. I was wondering what that wire carried . I have a 91 honda 60 amp setup i was going to wireup was not sure if that was a good thing or not, now i know it is
Jomama
Lucideye
ttt
Is there a particular reason for the length of this being so short on the 80 series? I've been working on the Urban Land Cruisers battery cable replacement install for my 80 and they provided a duplicate with the package, but it remains the stock length.
Does length factor in to the function of this type of fusible link? Is there a reason they cant be replaced with a longer setup?
Its the limiting factor afa enough length to reach center terminal mount batteries..
Is there a particular reason for the length of this being so short on the 80 series? I've been working on the Urban Land Cruisers battery cable replacement install for my 80 and they provided a duplicate with the package, but it remains the stock length.
Does length factor in to the function of this type of fusible link? Is there a reason they cant be replaced with a longer setup?
Its the limiting factor afa enough length to reach center terminal mount batteries..
Last edited:
The length is very important fusible links are rated amps per inch or foot.
Pink | 30 amp | |
Green | 40 amps | 0.50mm² |
Red | 50 amps | 0.69mm² |
Yellow | 60 amps | |
Black | 80 amps | 1.25mm² |
Blue | 100 amps | |
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The EWD calls out the sq mm of each fusible link. Match that with a fusible link table and you have the current rating.
Of course, as Phil says, $11 gets you the real thing.
cheers,
george.
Of course, as Phil says, $11 gets you the real thing.
cheers,
george.
MoJ
Moderator
Sounds like ~$11 will get you the proper rating
I have two spare fusible links that I’ve carried for 19 years. I’ve long thought of a troubleshooting situation where one burns through multiple fusible links before the root cause is confirmed. If the rating of the factory links was known it would be much better to have an in-line blade fuse receptacle on hand to burn through during the troubleshooting process. I might even cobble together such a test harness and offer it for sale on a very basic google storefront...maybe for 11 bucks.
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A blade fuse will blow much faster than a fusible link since the fusible link is intended to withstand short overcurrent situations.
So, 19 years with 2 spare links and you haven't needed one yet.... Seems that the troubleshooting process may need to wait a bit longer eh?
cheers,
george.
So, 19 years with 2 spare links and you haven't needed one yet.... Seems that the troubleshooting process may need to wait a bit longer eh?
cheers,
george.
MoJ
Moderator
A blade fuse will blow much faster than a fusible link since the fusible link is intended to withstand short overcurrent situations.
So, 19 years with 2 spare links and you haven't needed one yet.... Seems that the troubleshooting process may need to wait a bit longer eh?
cheers,
george.
I’m considering a situation where the fusible link blows rapidly and repeatedly when replaced. In this scenario it would be preferable to burn through fuses rather than links while troubleshooting. While I’ve accumulated two working but used spares over the years I could easily see not getting the issue fixed on the first go.
I’m considering a situation where the fusible link blows rapidly and repeatedly when replaced. In this scenario it would be preferable to burn through fuses rather than links while troubleshooting. While I’ve accumulated two working but used spares over the years I could easily see not getting the issue fixed on the first go.
Many times when troubleshooting you can put a light bulb in series in place of the fuse. When the light goes out you have found/cleared your problem.
