Fusible Link Size?

[DJ_Baar]

Attached pictures are from a wire I removed that is SUPPOSED to be a fusible link. I have used 30 amp fuse in line with replacements before. Just wanted to confirm that is correct size?

Mind you I found this early, but had a doooh moment when I replace fried wire (last picture) before looking at schematic. Easy fix, just want to get the amperage right.


R/
DJ

[leftybass209]

I pulled this straight from my automotive electricity book, so it's fairly accurate:

"A fusible link is usually four wire numbers smaller than the wire of the circuits it protects. For example, a 12 gauge circuit is protected by a 16 gauge fusible link. The special thick insulation over the wire may make it look larger than other wires of the same gauge number".

Remember, a fusible link is a BACKUP system only! In OEM applications, it is used in conjunction with individual fuses.

[DJ_Baar]

Question, what about a slow-blow fuse instead of a fusible link so it can be replace easier?

I definitely need to remove the heavy AWG wire there now.

[leftybass209]

Originally Posted by DJ_Baar

Question, what about a slow-blow fuse instead of a fusible link so it can be replace easier?

I definitely need to remove the heavy AWG wire there now.

What circuit/s will this be operating? Without getting too technical, a slow blow fuse can "tolerate" more frequent amperage spikes without blowing as opposed to a standard fuse, which usually pops at the first sign of high current.

I would never run a slow blow fuse on any typical vehicle circuit because it's just not how automotive electrical devices were designed to operate.

A fusible link is more reasonable for most automotive applications.

A circuit blowing isn't usually just a happenstance, but a warning that something has shorted, or is wired incorrectly. Certainly it needs to be diagnosed, rather than just replacing the fusible link or fuse and moving on.

[Big Kev-O]

You should never have to replace the link if your circuit is protected with the proper size fuse. You have to severly overload or direct short a fusible link in order to burn it up. A slow blow fuse could be used but it is best to use a fuseable link because they never fail. They burn up to protect the rest of the vehicles wiring. Fuses are fragile and can crack from heat and vibration. Most local parts stores have fusible link in stock. The question that needs to be answered is why didn't a fuse blow before the link burnt up? Like stated above you need a fusible link and a properly sized fuse. That said, I would never replace a factory fusible link with a slow blow fuse.

[DJ_Baar]

OK, you have me sold on fusible link.

I found this page, http://www.madelectrical.com/catalog/fusible-link.shtml

But since I do not know original size, back to question what size?

I found this drawing (attached) on another post as example, no wire size listed.

[DJ_Baar]

Perhaps I answered my own question, in the drawing is the wire number the AWG and the color the letter?

[leftybass209]

Originally Posted by DJ_Baar

Perhaps I answered my own question, in the drawing is the wire number the AWG and the color the letter?

Yes, AWG followed by color. If it's something like B/W, it's black with a white tracer.

[DJ_Baar]

Roger that, so Fusible Link "16R" is 16AWG Red?

This is the correct schematic for Chevy C10,20, & 30.

[dmjlambert]

Yes, red, although you may have difficulty finding your choice of colors of actual fusible link wire in any old store. I got some from O'Reilly Auto and it is grey and 16 gauge. When I asked the question a few months ago, forum member ray_mcavoy answered back some good info:
http://67-72chevytrucks.com/vboard/s...d.php?t=705203

This is how mine ended up looking. I used crimp terminals and the fusible link goes between the battery and terminal block, and I used a piece of heat shrink tubing for neatness and strain relief. I oriented the battery with the positive terminal closest to the terminal block, so my fusible link is between 6 and 9 inches as ray_mcavoy advised. If I had a longer distance to go, I would have soldered a short length of 12 gauge wire to the fusible link wire and used heat shrink tubing on the joint, then the total length of wire between the battery and terminal block could have been a little longer and yet have a fusible link of 6 to 9 inches.

According to wikipedia "The wire in an electrical fusible link is encased in high-temperature fire-resistant insulation to reduce hazards when the wire melts." I have heard that the insulation is made specifically to smoke to get your attention and to make it obvious you have a problem, but I can't substantiate that.

[DJ_Baar]

Roger that DMJLambert - thank you.

[ck5566]

This is for DJ_Baar the New Orleans party man; Use the Search button drop down window & type in Re:Color Wiring Diagram FINISHED, another drop down window shows multiple choices, look for a "locked thread", Author is boundstaffpress, Liz put in a post on 04/02/2011 @ 1:30 pm its the last post in the thread #4th, her post has only two entries, also each one can be enlarged showing all wire sizes 7 colored wires.

This should give you all info that you need for wiring sizes (AWG) & colors of the wires

[DJ_Baar]

Thank you ck5566.

[DJ_Baar]

Got fusible link and a spare and hooked-up to in series with POS lead to terminal per schematic and correct gauge (16 AWG).

R/
DJ

[dmjlambert]

I am going to revise my previous reply in this thread. In the picture I posted above, I have a "repair" terminal, where the stripped starter wire is clamped to the terminal that is clamped to the battery terminal. I have been burned by this, because the wire connection deteriorated, worked loose, and gave me a high resistance connection during attempted starts, and I believe I misdiagnosed a starter problem. I am now a believer that these repair terminals are junk and I will not have another one on a vehicle of mine. I got new assembled cables from O'Reilly and I am much more confident in the reliability. My connections look more like this now, pictures attached. Soldered connection to the fusible link, with heat-shrink tubing. Boots from eBay, I searched for "battery terminal marine boots," I think these are a good find.
http://www.ebay.com/itm/301287514282

[DJ_Baar]

I like the boots - GREAT idea, keeps protective cover over terminals and corrosion protection on them too.