Lately, I've been wanting to add some hidden circuit protection on the original main power feed from the alternator on my '64 Belvedere. However, hiding a high amp circuit breaker near the alternator has proven to be difficult. I've looked at Maxi-fuses and the larger, marine-style circuit breakers. Both are kinda big and hard to hide.

I've added an additional wire from the alternator to the starter relay to reduce the load on the bulkhead connector, and that wire incorporates a fusible link. But the original doesn't have a fusible link, and I really don't want to cut the engine harness to add one unless I absolutely have to.

So last night, this idea popped into my head: Adding a manually reset circuit breaker to the original power feed that mounts to the ampmeter in the dash. It would be easy to hide behind the dash, and I'm thinking a lower amp (20 amp??) circuit breaker would power the interior circuits, but "pop" fairly quickly (protecting the bulkhead connector and interior wiring) if there is an electrical short of some kind.

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Decent, but not great, idea? Bad idea? Obviously, the circuit breaker is a long way from the alternator, which isn't good. But I wanted to see what everyone thought about this.

If adding a fusible link the original power feed is the only acceptable answer, would two fusible links "in parallel" (original power feed and add-on power feed) blow quick enough to protect the wiring? I'm planning to swap to a 90-amp Denso alternator this winter, but want some kind of protection in place before I do that.

I did it differently since I don't care about how original it looks.
I figure 30 amp is good since the original alt was 37 amps and powered the whole car.
I think there is more in the passenger compartment power draw wise than in the engine compartment.
If you relayed the headlights, then my guess is about even.

I fused it instead of a breaker, but that would work too. I also fused in incase I needed room to grow. Power windows and what not. Then I just needed to buy a 5 dollar pack of the higher amp fuses, or feed it off another line.

Keep in mind that really are only protecting the power feeds to the fuse block and ammeter. Most all of the branch circuits are fuse protected (with MUCH smaller trip limits than what you are contemplating) and will blow long before your breaker or beefy fusible link. You are talking about adding additional connections (a source of problems/shorts) in a relatively short distance of a circuit (dash to alt). I would think your concern would be better spent making sure your alt to fuse block power feeds are in top-notch shape and routed in manner to avoid trouble (abrasion or heat). Make sure connections are clean and tight--including the ammeter!

I guess my main worry is the denso alternator "overpowering" the electrical system in the event that it goes "full charge" (dead battery or internal alternator fault). I can see the fusible link on the extra charge wire blowing, and the full current is then trying to go thru the engine harness and bulkhead connector. I'm thinking the result would be overheated/melted connections at the bulkhead connector and melted wiring.

As I understand the original electrical system, the current path goes thru the bulkhead connector to the amp gauge. Then out to the rest of the systems (headlights, heater, etc). So, with that in mind, I'm thinking a circuit breaker at the amp gauge connection could isolate that power feed to some degree.

I've already put the headlights on relays with separate, fused power leads and made up a new headlight harness with larger gauge wire. I've also added an extra ground wire between the engine block and frame since the factory one is a little small. The bulkhead connectors have been individually removed and cleaned for good continuity. And the engine compartment harness is new and well protected.

Again, any advice or comments are greatly appreciated.....

OK, but the situation of going full charge that you describe would feed power through the existing fusible link???? (at least if the 'load' is the battery). If its a short under the dash, they you would have two problems.

Yeah, the problem would be the bulkhead again, not the amp meter. It would burn out their first, and melt through to other lines.
I would put it in the engine compartment. I bypassed the whole bulkhead connector for power, so I put the fuse inside. But you may have to put it on the outside.