Amp Breaker

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I used similar breaker on my boats, never had to reset one.

Installed them after I had an alternator internal grounding.

Wood/fibreglass burns really well, - and you can't get out and walk.

I guess they worked great
 
Inertia said:
I used similar breaker on my boats, never had to reset one.

Installed them after I had an alternator internal grounding.

Wood/fibreglass burns really well, - and you can't get out and walk.

I guess they worked great
Click to expand...
I appreciate it, thanks.
 
Also wondering it there is a better strategic place to install it for best protection... ??
 
I installed them as the first junction after the starter solenoid, they provided power to ALL " appliances "/accessories.

In a Mopar, I'd try for right beside the starter relay by the battery. jmo
 
Inertia said:
I installed them as the first junction after the starter solenoid, they provided power to ALL " appliances "/accessories.

In a Mopar, I'd try for right beside the starter relay by the battery. jmo
Click to expand...
so in between the relay and the battery? Or after the relay on the positive post?
 

As close to the relay as possible on the non battery side,and as far away from heat as possible. Breakers are thermal devices and a hot environment will cause them to trip under less load.

Cley
 
You want to make sure:

Numbaw wone: that a breaker will protect the WIRE

and in the case of this application,
no. teu: that it's large enough not to trip on the alternator output.

Do you have an ammeter bypass?

I can GUARANTEE you that in some cases, the OEM fuse link DID NOT protect the original harness, and the proof is "me" around the early 1970's, a slant loaner junker from the Plymouth dealer that was "fixing" the body on my 70RR

A diode had fallen out of the alternator, down inside, and ended up shorting. So the charge wire (black) from the alternator, up through the bulkhead, through the ammeter, back out (red) through the bulkhead, sat there and fizzled and burned and melted as I watched. It always reminds me of this, without the water:

 
Mattax said:
Circuit protection is sized for the weakest component you need to protect.
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I thought it would be the amp of the alternator. 60 amp alternator = 60 amp Circuit protection. Is this wrong?
 
318willrun said:
I thought it would be the amp of the alternator. 60 amp alternator = 60 amp Circuit protection. Is this wrong?
Click to expand...
As was mentioned before, the circuit breaker is meant to protect the wire. In this case it must be at least 60 amps because that is what could be flowing from the alternator to the battery.

Cley
 
318willrun said:
I thought it would be the amp of the alternator. 60 amp alternator = 60 amp Circuit protection. Is this wrong?
Click to expand...
It is wrong.
Take house wiring for example.
If there is 14 gage wire in a circuit, the circuit gets a 15 amp breaker or fuse.
If it is all 12 gage wire, then a 20 amp breaker is allowed.

My guess is the code doesn't worry about the lamps and fixtures themselves because they are outside of the walls and you will notice the bulb go out.

The '60 amps' is just a manufacturer's approximation of maximum current at some voltage. Kindof like Holley's 750 is an approximation of cfm at 1.5" (or something like that )
 
Clelan said:
As was mentioned before, the circuit breaker is meant to protect the wire. In this case it must be at least 60 amps because that is what could be flowing from the alternator to the battery.

Cley
Click to expand...
I agree with your statement. But 60 amps would be really bad for the battery.

The maximum safe current to a battery can be approximated from the CCA or the Amp-hours but its going to be much less than that on a typical car battery we use. A quarter of the Ah rating.
Posted some links here
 
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My thinking on a factory system is that any short will shut down the alternator.
(a) current flows to ground so why would it go through the rotor? the rotor is not the easiest path.
No field = no power out.
(b) current flows to ground so why would it go the ignition? No ignition = no engine = rotor stops turning and no power out.

The fusible link or links is to stop the battery from discharging when an unfused circuit shorts. On our cars it really only protects the main feeds. Its a 16 gage wire so its not going to protect an ignition wire that's also 16 gage (or even 18 gage).
 
Mattax said:
My thinking on a factory system is that any short will shut down the alternator.
(a) current flows to ground so why would it go through the rotor? the rotor is not the easiest path.
No field = no power out.
(b) current flows to ground so why would it go the ignition? No ignition = no engine = rotor stops turning and no power out.

The fusible link or links is to stop the battery from discharging when an unfused circuit shorts. On our cars it really only protects the main feeds. Its a 16 gage wire so its not going to protect an ignition wire that's also 16 gage (or even 18 gage).
Click to expand...
so what amp circuit breaker would you recommend?
 
318willrun said:
so what amp circuit breaker would you recommend?
Click to expand...
I'm not recommending anything. I'm saying its not based on the alternator.
And its sure not based on the battery.
You have to identify the weakest wire or connection you want to protect.
There's some charts and on-line calculators that help figure the maximum current for a wire without overheating.
I think West marine and Blue Sea Systems have some on their websites. Maybe Wire Barn too.
 
Here's one that might have had a web based calculator when I first bookmarked it.

WireSizer App for iPhone & Android

WireSizer is the intuitively easy DC Voltage Drop Calculator for iOS and Android devices to find the RIGHT sized wire gauge needed for a desired voltage drop for DC circuits.
www.wiresizer.com www.wiresizer.com

A lot of info at

This is more for figuring out the wire size
 
Mattax said:
I'm not recommending anything. I'm saying its not based on the alternator.
Click to expand...
Assuming the wire gauges are correct, wouldn't the size be based on the amperage draw of the system ? I think you could have a 200 amp alternator but doesn't mean it will produce 200 amp unless the system needs to draw 200 amp ?
 
273 said:
Assuming the wire gauges are correct, wouldn't the size be based on the amperage draw of the system ? I think you could have a 200 amp alternator but doesn't mean it will produce 200 amp unless the system needs to draw 200 amp ?
Click to expand...
Yes. That's the way a power supply works.

Then wire sizing is based on the current draw of the equipment, and the distance and temperature of the wire route.
The circuit protection is then based on the wire size, unless you want to protect the equipment with a fuse.
 
All of my classics are "bare minimum" on accessories. Wipers, lights, heater fan. I'm not a wiring specialist, and I've seen so many ways people protect their investments.
  • Run a large red wire from the +power on the alternator to the starter relay + post.
  • Some put the amp gauge wires on the same post so the gage doesn't melt down. Then install a volt meter gage instead.
  • Some have bypassed the amp gage at the bulkhead.
  • Now, I watched a video where Steve D. went to A/C and used a circuit breaker after the relay AFTER he installed a 120 amp alternator.
All make sense but the CB Steve used and where he used it. Trying to see and learn, protect my investments.

Currently, none of my cars are burning (since I last looked.. lol)
 
If you run a wire from the alt to the starter relay, you will want to fuse that wire too.
 
318willrun said:
All of my classics are "bare minimum" on accessories. Wipers, lights, heater fan. I'm not a wiring specialist, and I've seen so many ways people protect their investments.
  • Run a large red wire from the +power on the alternator to the starter relay + post.
  • Some put the amp gauge wires on the same post so the gage doesn't melt down. Then install a volt meter gage instead.
  • Some have bypassed the amp gage at the bulkhead.
  • Now, I watched a video where Steve D. went to A/C and used a circuit breaker after the relay AFTER he installed a 120 amp alternator.
All make sense but the CB Steve used and where he used it. Trying to see and learn, protect my investments.

Currently, none of my cars are burning (since I last looked.. lol)
Click to expand...
A lot of people do a lot of things.
Nothing wrong with the factory setup for factory like you have.
If the car has anything other than the 6012 headlights, then a relay harness powered from the alternator will (a) protect the headlight circuit, (b) provide brighter lights, (c) divert those 9-10 ampos so they never go through the bulkhead connector or the main splice.

A voltmeter doesn't show battery charging or discharging. It shows system voltage at the location its connect to. From that we must assume the charge rate is OK. It doesn't show if the charge rate is 5 amps or 50 amps.
The ammeter doesn't show voltage. We assume when it shows normal charging and discharging that the system is OK, and when it shows something like discharging while the engine is running, the alternator isn't working.

If you like videos, there's a bunch in this thread from a guy delving into this. I didn't watch them but he seems to understand the issues.
 
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