JasBass

Has anyone out there converted the fusible link bundle on the driver's side power block to a true fused setup? Cleaning up the harness and sorting a few things. Thought this might be a nice project while I was in there and also add some more modern safety

WVZR-1

The links actually serve a very useful purpose, they'll absorb a high current surge without blowing where if "fused" the wiring to the fuse box would/could be destroyed until the fuse blew. A friend uses fusible links where they're OEM and in some street-rod projects where the wiring is "all his" he does differently more like the later C4's with under-hood fuse boxes that use MAXI etc.

Older wiring where insulation is shrink and connectors have aged I'd think I'd leave the links. It might be interesting to maybe identify and tag them while cleaning.

JasBass

Older wiring where insulation is shrink and connectors have aged I'd think I'd leave the links. It might be interesting to maybe identify and tag them while cleaning.[/QUOTE]


Very interesting, I never thought about it from the standpoint of the box itself melting before the fuse blew. Every time i'm working on that driver's side, my OCD kicks in looking at that link bundle. I'm starting to understand a clean wiring install on the C4 engine bay is a pipe dream. I appreciate the info my friend

BlowerWorks

OK guys ! I am upset here !!!! Grrrrrrrrr !

Why not first ask why 'fusible link' vs. 'fuse' ????

Later - greg

ddahlgren

Why not circuit breakers?

Kevova

Splitting off circuits to into individual fuses happens mostly when trying isolate intermittent shorts.

BlowerWorks

Resistance ...........

arbee

.........to what?

Kevova

Fusible links wire is designed to "pop" anywhere along it. They typically protect feed circuits to fuse boxes. If a fusible link chaffs shield or is burnt by manifold it "pops". Regular wire may cause fire.

Circuit breakers don't come in all sizes. Because they reset is good in some cases, but can cause harness damage in others. Since the power continues to cycle until wiring burns or circuit breaker fails. There can be extensive damage as a result.

ddahlgren

They can be had auto and MANUAL reset

Kevova

In general automotive use circuit breakers are self resetting. Manual resetting are for specialized applications in regards to automotive. In a racing application the manual resetting fuse/ circuit breaker is handy in being able to quickly identify electrical troubles.

arbee

Can you explain this statement further and where you acquired this information?

Kevova

Invest in a automotive electrical text book. Fusible link is not standard wire, it's intended for a certain amount of current and melts when it is exceeded. Regular wire the whole wire will carry the current it doesn't have a limiting factor. A 14 gauge wire coming off battery if shorted to ground will carry the 525 amps to ground until wire melts. The heat generated can cause a fire. Fusible link is less than 12 inches usually and won't carry nearly that much current. The maxi fuse is replacing fusible links where battery cables are used to provide power to fuse and relay center. Battery cable is routed so there is little chance of shorting to ground.

arbee

You might want to re-read your automotive textbook. ALL wire melts when its current carrying capacity is exceeded. Fusible links are generally 4 AWG sizes SMALLER than the wire they are connected to so it melts first. Other than a non-combustible sheath, the copper wire inside is no different than any other copper wire. I can guarantee you that a 14 gauge is not going to carry 525 amps very long! How fast can you blink?

Kevova

The 525 refers to the cca of a 12v battery. 14 gauge wire does always go poof when shorted. Alternator output wire would be 12-14 accidentally grounding are wrench does not melt the wire immediately might burn your hand severely if it trapped. Fusible links are supposed to be 4 gauges smaller. The composition of the wire is different. Metals melt at different temperatures. I've done my share of underhood fire and overheated wiring repairs. Back to the subject use fusible link were necessary not general purpose copper wire.

arbee

Your statement above is exactly what I told YOU in my previous post. If you think that fusible link copper wire has a different composition and this is what provides the protection, try a little experiment for me.(try it on your car) Take a 16 gauge fusible link and tie it into a 16 gauge branch wire. Now, cause an intentional short and see what happens. By your way of thinking, the link should protect the conductor right? You willing to try that? The protection is provided by the fact the current carrying capacity is less than the conductor it is protecting and it will melt first. Your thoughts would suggest there is no need for the link to be smaller than the circuit it is protecting, even though you agree that is the installation criteria. I have included a link below from a major cable manufacturer that manufactures this wire. The first item under "Fusible Link Cable Construction" says that the conductor is bare copper wire - no mention of any special composition. Post up a link supporting your claim so I can study up.

http://www.awcwire.com/ProductSpec.a...ible-link-wire

Hot Rod Roy

My '84 FSM shows fusible links by their conductor sizes.
For harness wire of 5.0sq.mm (10awg), link is 2.0sq.mm (14awg).
Harness wire 3.0sq.mm (12awg), link is 1.0sq.mm (16awg) or .5sq.mm (20awg).
Harness wire 2.0sq.mm (14awg), link is .5sq.mm (20awg).

Fuses require sockets, which are subject to moisture and corrosion. Fusible links are sealed. A f/l can be put anyplace, rather than having to route the wire to a weather protected fuse panel. I would also suspect that the cost of a f/l is less than the cost of a fuse and socket.

Red 91

I look at FL the same as slo-blow fuses.

WVZR-1

Greg was the guy that "growled" and he's not returned to expound regarding.

Wonder why!

If a car is used in daily driving, wired originally with fusible links it just makes sense to repair and leave stock. You start changing things to suit yourself you certainly could diminish the resale and also likely reliability if you're less than an EXPERT. When wired as original all FSM documents are certainly more effective for diagnostics.

A heavily modified car certainly might be a candidate for something 'other than original' but that I believe up to the individual. A C4 with the battery block and NOT modified I can't see any reason for changing!

arbee

You are exactly right. That is their purpose. Protect the circuit yet allow momentary in-rush currents.