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Fusible link question

3K views 9 replies 6 participants last post by  onovakind67 
#1 ·
I recently replaced my fusible link wire at the battery pros cable because it was really flimsy feeling almost like it was broken and the only thing holding it was the wire sheathing. Anyways the parts store told m a in line 30a fuse would be fine but after doing the changout I was blowing fuses after the engine was running , it ran good but would not start again until the fuse was changed out. I've read on the posts that a. Inline fuse would not work like a fusible link. I would like to know the difference if anyone has the answer , I plan on changing out the fuse and going back to a fusible link 14 ga this when'd but I'm curious as why it's doesn't work the same way . Does the voltage spike that much to blow the fuse and if so I would think the fusible link would too ?? Any feedbacks are welcome , arvin
 
#2 ·
It is my understanding that a fuse will blow instantly where a fusible link will take a brief spike and not blow. That is why the factory installed fusible links. I recently blew the fusible link coming off the battery positive post. I replaced it with a fuse as the auto parts store recommended and the fuse blew a couple of times. I ended up going back to a fusible link and all is good. The reason my original fusible link blew was a new ignition switch I installed (made in Mexico). Hope this helps.

Bill B.
 
#4 ·
A time delay fuse will take a spike in power before blowing also.
The fusible link is a kind of like a time delay fuse. A copper 14 gauge wire amps is rated at 30 amps, it can take more amperage then the 30 amps for a little while. The insulation will begin to melt then the wire strains begin to melt.
 
#7 ·
I'll take a good fuse of the proper rating any day. Fusible links add considerable resistance to the circuit, for this reason Ron Francis wiring systems do not use or recommend them. Two sides to every story etc.
 
#10 ·
How much resistance do they add? Let's say that we are fusing a 6' 10 gauge power wire with a 6" 14 gauge fusible link.

10 gauge wire - 1 ohm/1000ft so 6' of wire has .006 ohms, 6'6" of wire has .0065 ohms.
14 gauge wire - 2.5 ohms/1000ft so 6" of wire has .00125 ohms. Add that to the .006 ohms of the 10 gauge wire and you have .00725 ohms. Subtract .0065 from .00725 and get .00075 ohms added because of the fusible link. I'll bet a 30 amp fuse has just as much resistance as a fusible link.

https://w220.ee/DIY_Voltage_Drop_Across_Fuses_-_Quiescent_Current_or_Parasitic_Discharge_Tests
 
#8 ·
Arvin, not sure what year Chevelle you have. I assume it's a 70 from your profile. FWIW, my 68 SS has 2 other fusible links. One to the horn relay bus and one leading from the horn relay bus to the interior. If I remember correctly those are 14 gauge links. I changed them out also after I blew the one from the battery. Glad I did as they were still working but a lot of the strands were broken. Something you might want to consider.

Bill B.
 
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