A tangent from the preparedness thread.

What are the pros and cons of breakers vs. fuses. On the surface I'd think breakers would be the obvious choice, but so many cars are running relocated fuse boxes and still running fuses.

Pluses, minuses??

I'd have thought breakers would be fairly high up the order of preparation but that isn't borne out by observation. what I see.

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john vanlandingham
Blame is for idiots. losers.

I would just say cost/time to prepare a harness for breakers. Relocating a stock fuse box is pretty simple work, my VW I moved it without the need to lengthen any wires. On the Honda, OEM location was good enough inside the car.

Breakers since 1985. Cost negligible when having problems.

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So, how is a breaker safer than a fuse? Because if the fuse blows, isn't it usually because of a bad thing and you WANT it to blow? How would being able to just flip it back on be helpful?

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Dazed_Driver
So, how is a breaker safer than a fuse?

I don't think anyone here said breakers were safer.

Being able to push them back in and get through the stage before diagnosing could be handy. Diagnosis of 'which' breaker has blown can (should?) be easier than with fuses.

Essentially, faster and quicker than just replacing a fuse. (How many times do people just replace a blown fuse without really understand WHY the fuse went? I'd bet more often than not.)

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john vanlandingham
Blame is for idiots. losers.

I got a good example of why a breaker is better than a fuse: I had a 10a or 15a breaker for the fuel pump which was fine and worked perfect for a while until I found out that on long prolonged times of full throttle and when off throttle it would make it trigger. I laters switched to 20a, but in the meantime it meant that no time was lost with just a simple click. The price is not too bad either so its worth going to breakers.

Oh, so its not a safety thing, its a helpful thing. Gotcha.

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Welcome to the cult of JVL drink the koolaid or be banned.

I'm an EE. We use both regularly, for different applications


Fuses are cheaper, they are by far more accurate as there's no real mechanical component, also their response time is much quicker. Usually a smaller package as well.

For a car well yeah, breakers might not be a bad idea if you could get breakers small enough to fit in the space you want.



Edited 1 time(s). Last edit at 05/15/2012 09:22AM by czwalga.

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Cosworth
I got a good example of why a breaker is better than a fuse: I had a 10a or 15a breaker for the fuel pump which was fine and worked perfect for a while until I found out that on long prolonged times of full throttle and when off throttle it would make it trigger. I laters switched to 20a, but in the meantime it meant that no time was lost with just a simple click. The price is not too bad either so its worth going to breakers.

Wouldn't it have been easier to just throw a 20A fuse into the slot than have to replace a breaker? 20A fuse could be swapped out on stage.

To Steve's point about accuracy, I thought I remember somebody saying that a repeatedly tripped breaker could allow a much higher current, and increase the possibility of wiring shorts.

Don't forget that breakers do go bad, and they are usually not your first inclination. I'm not sure how many of you keep a meter in your rally car, but a bad breaker puts you in a shit situation. Unless you packed a spare breaker and can identify it was a bad, how many of you would think to replace the breaker?

If you were to wire an LED to each of the breakers indicating an on or off situation it may make troubleshooting them and problems with the rest of the car much easier.

And then, what if you had an overvoltage that burned out some of your LEDs?

Better have a backup regular bulb that tells you that your LEDs are working that tell you that your breakers are working that tell you that your fuel pump is working.

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Grassroots rally. It's what I think about.

lol, Sorry I'm a medical equipment guy. Redundancy, over complicated and limited feedback to the end user is in my blood.

But it does only take an extra 30 minutes to add an LED to your major couple of breakers. Like the fuel pump, and ECU stuff.

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aj_johnson
lol, Sorry I'm a medical equipment guy. Redundancy, over complicated and limited feedback to the end user is in my blood.

But it does only take an extra 30 minutes to add an LED to your major couple of breakers. Like the fuel pump, and ECU stuff.

You'll need a resistor along with a LED, since LED's blow up with a 12v drop. But then we need to get some indication that the resistor is now ok, and didnt break causing the LED to break! Would would be ideal is if you got 4 LEDs in series screw the resistor... that would do the trick.



Haha... sorry just having fun.

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czwalga
I'm an EE. We use both regularly, for different applications.

What are the factors in the choice of fuse vs. breaker?

We see breakers regularly in aviation applications but I would have thought that in mass production (auto) applications cost savings would be the primary factor followed by size.

---

First Rally: 2001
Driver (7), Co-Driver (44)
Drivers (16)
Clerk (10), Official (7), Volunteer (4)
Cars Built (1), Engines Built (0) Cages Built (0)
Last Updated, January 4, 2015

Quote
john vanlandingham
Blame is for idiots. losers.

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Morison

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czwalga
I'm an EE. We use both regularly, for different applications.

What are the factors in the choice of fuse vs. breaker?

We see breakers regularly in aviation applications but I would have thought that in mass production (auto) applications cost savings would be the primary factor followed by size.

For what I do (saftey systems for nuke plants), response time matters a lot. We tend to use breakers for power distribution and fuses for individual signal isolation.

Obviously anything that you'd like to be switched on and off a breaker is a huge advantage. In a vehicle how often do you ever need to turn off your fuel pump? Never... this is probably a loaded question because people on here obviously tinker way more than the general public.

In the end for cars, theres no reason to go with breakers for regular cars. They are like you said more expensive, and larger. Think how big your average 15 amp breaker is, vs all the tiny fuses used in a big fuse box. Size and Cost for sure.