What size fusible link should I use?

This is for "general" electrical discussions. Audio, security, remote start, and power accessories should go here, since they don't seem to fit anywhere else. Not for diesel-specific (like glow systems), or gasoline-specific (like ignition systems) topics.
Red Truck
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What size fusible link should I use?

Postby Red Truck » Fri Jun 21, 2019 11:50 am

After reading a recent post about a faulty f-link, I decided to get a spare for my rig. I find it con-fuse-ing. From what I've researched (including this forum), there is literally a rainbow of colors and gauges to choose from, and depending on which reference is used, a different amperage value applied to the same part. I've found an OEM part #5826590470, but it's for a diesel, and I believe that makes a difference. I've found no mention of a gas application. So, here's what I have:
On the truck now, is a black fusible link wire coming off the pos battery clamp, attached by an eyelet. There's a section of red braided fabric, about two inches long, covering the black wire where the eyelet meets the battery clamp (at the post). The black f-link wire then connects to a plastic plug, about 6 inches downstream from the battery post. There are no 'trick' add-ons to the vehicle's electrics, still has stock alternator, lighting, and ignition, no A/C. What size (14, 16, 18 gauge) fusible link should I get for a replacement?
'87 Isuzu pickup 2.3 gas, 5spd, 4WD

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puttputtinpup
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Re: What size fusible link should I use?

Postby puttputtinpup » Fri Jun 21, 2019 7:22 pm

Read through this thread. viewtopic.php?p=125561#p125561

Hope it helps

JLEMOND
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Re: What size fusible link should I use?

Postby JLEMOND » Sun Jun 23, 2019 3:58 pm

factory fuse liks clors are as follows

BROWN ====13 AMP

GREEN =====16 AMP

RED IS =======21 AMP

BLACK ==========26 AMP

BLUE IS 30

Red Truck
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Re: What size fusible link should I use?

Postby Red Truck » Sun Jun 23, 2019 5:08 pm

Thanks for the replies. Planetisuzu has some interesting posts on the subject, but no definitive answer (to me, anyway!) What I think I'll do is drop by NAPA and tell them what have, and see what they try to sell me, 'force their hand', in other words. I'll end up buying from them, anyway. Maybe they'll show me a reference. I believe a 16 gauge 26 amp black wired fusible link is what 'm looking for, but they also offer 14 and 18 gauges...and the significance of that red wrapping material remains a mystery. I dunno. I'll pass on what NAPA comes up with.
'87 Isuzu pickup 2.3 gas, 5spd, 4WD

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puttputtinpup
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Re: What size fusible link should I use?

Postby puttputtinpup » Mon Jun 24, 2019 4:38 am

I think proper length and gauge to match the original is the answer, rather than the color. Use Jerry's list as a reference to the gauge you need.
My only experience with my fusible links was to remove the wire from the connector and open up the metal crimp, clean up the end of the link wire and crimp it back really well.
Good luck!

Red Truck
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Re: What size fusible link should I use?

Postby Red Truck » Wed Jun 26, 2019 2:19 pm

NAPA provided me with a 16 gauge f-link, their part# 784694. This is for a gas application, the diesels are different, they say. There is no reference for this (gas version), other than a clerk said he used the same part on his similar truck (!?!). The 16 gauge NAPA part protects up to 22amps, and with the Isuzu color code of red, noted above (and elsewhere), up to 21 amps, I feel confident it should be okay. I also used a 3/8" crimp blade connector and crimp eyelet.
I separated the plastic connector of my old f-link, hoping to be able to measure its gauge somehow, and it crumbled apart in white and copper powder. It must've been because of my good looks that it kept a connection at all. The NAPA people and I agreed that the short red section of the old link must signify its rating, and it's wire diameter of .058" corresponds to a 16 gauge. It is said that the f-link size should be about 4 gauges smaller than the wire it protects (which goes to the alternator and ignition, I think) which is about .130" in this case, or about an 8 gauge wire. That would mean a 12 gauge fusible link, which isn't realistic for this application. So, I basically went with the wire gauge/rating that was there before.
'87 Isuzu pickup 2.3 gas, 5spd, 4WD