Circuit Breaker Panel offering From Steinair

Yesterday I flew N199MJ back up to Sebastion (X26) to get a few issues corrected with software and got my first look at the circuit breaker panel that Stein made for us to replace the auto fuse type panel that came with our kit. We were never really comfortable with the fuses so we went with this prototype design as a replacement. It really is a work of art. I spoke with Stein and he informed me that the pricing would be similar as to what the fuse panel is as it varies with the way the panel is configured on each plane. IMHO, this is a superior way to go.

woodmanrog said:

We were never really comfortable with the fuses so we went with this prototype design as a replacement....IMHO, this is a superior way to go.

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Can you tell us why?

Some folks just don't like fuses. When I expanded the electrical system on our aircraft to include an essential bus, I purchased all the fixin's to do so using fuses. After it took me more than a month to get started on the wiring I realized the delay in starting the job came about because I felt that nagging feeling that fuses were just not the right way for me to go. Once I had made up my mind (and found the real estate) to install an ESS Bus circuit breaker panel, I felt a wave of relief. I really hadn't understood how uncomfortable I was with having essential equipment powered by fuses which would, for all practical purposes, be inaccessible in flight. I guess I've just spent too much time in aircraft with circuit breakers.

To each his own - if you're like me and fuses make you uncomfortable, well, there are other options!

Canadian_JOY said:

To each his own - if you're like me and fuses make you uncomfortable, well, there are other options!

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Again, why do they make you uncomfortable?

DanH said:

Again, why do they make you uncomfortable?

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Fobia de Cirquitus interuptus, just my guess!

If you have a short in flight that will pop the CB, guess what, unless a miracle fixed that short that caused the CB to pop in the first place, it is going to pop again. I have fuses just like the millions of highly sophisticated vehicles on the road today.

FWIW, I prefer CB's (and layout my custom panels as such), for things that are:

1) flight critical
2) Equip'd with processors that may need to be reset.
3) Equip that I may want to disable (ground ops mostly).
4) Items which I want the visible indicator of lost power which may otherwise go unnoticed (ie: field, elect ign, pitot heat).

Fuses are fine for everything else considered "non essential" equipment.

Walt said:

FWIW, I prefer CB's (and layout my custom panels as such), for things that are:

1) flight critical
2) Equip'd with processors that may need to be reset.
3) Equip that I may want to disable (ground ops mostly).
4) Items which I want the visible indicator of lost power which may otherwise go unnoticed (ie: field, elect ign, pitot heat).

Fuses are fine for everything else considered "non essential" equipment.

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Walt, could you offer an example of "flight critical", and state why a fuse would be inappropriate?

Resetting processors/ground disabling are maybe a bit more convenient with a pullable breaker, but there is no other advantage if the fuse block is accessible.

Lost power indication is interesting.

DanH said:

Walt, could you offer an example of "flight critical", and state why a fuse would be inappropriate?

Resetting processors/ground disabling are maybe a bit more convenient with a pullable breaker, but there is no other advantage if the fuse block is accessible.

Lost power indication is interesting.

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I'll not comment on what's appropriate/inappropriate...but I will mention an incident that happened to me once...

Most glider electrics use fuses, not CB's...for reasons I won't bore you with.

One time while flying, an inadvertent tug on some poor wiring I'd done caused a momentary short and my electric vario and nav computer went Tango Uniform as the fuses blew.

Those items are pretty important to staying up (finding lift) and getting home.

Flying (and replacing fuses) became a very challenging proposition, especially the lower I got....locating the baggie with the spare fuses, digging them out in, and getting the right sizes in the right holes....took way more effort than I expected.

Note: this was NOT in a fuse block, but individual "twist type" front load fuse holders like:

http://www.aircraftspruce.com/catalog/elpages/fuseholders.php?clickkey=13832

Did I mention that when you start getting really stressed, your fine motor skills (such as handling small glass fuses) go to hell?

Better wiring practices once I got home prevented another occurrence, but after that I flew with what I considered "essential fuses" taped under a piece of clear tape close by the relevant fuse holders.

Wouldn't want to be messing around with something like that while IFR...and that's why I like the easy reset capability of CB's vs using fuses.

My 2 cents.

You ask a good question, Dan. Why do fuses make me uneasy? Well, we use them in cars, but when the blow, we pull over to the side of the road to replace them. This renders somewhat inappropriate the car analogy used by many fuse fans.

Have you ever heard a CB pop in flight? That audible "ping" of a breaker popping is a "feature" that isn't available in fuses. When I purchased that stock of fuses I made sure they were the type with an LED that glows when the fuse has burned open - score a point for this type of fuse because I haven't seen any reasonably-priced CB's that come with that type of simple open-circuit indication system.

I tend to sympathize with Walt's comments on flight critical devices. I have an EFIS powered through a circuit breaker. While not a common happening, having to cycle power on complex electronic devices to give the box a cold re-start isn't unheard of (thankfully, not something I've had to do in my aircraft). I've done that same "hard reset" with equipment that spans a range from auto-flight computers in heavies, EFIS systems in homebuilts, targeting computers in attack helicopters and even a HUD in a particularly special Hercules. I've had CBs pop in radar systems when they were sparked up in very cold conditions.

Without doubt there are many instances where resetting a circuit breaker in flight is unwise (I can think of one particularly embarrassing situation where a DC-9 had its flush motor CB reset several times, resulting in a fire in the loo - definitely NOT a good situation). I can also rhyme off quite a few instances in my own experience where resetting a CB was a necessary action. In an operational situation, one has to make an evaluation of the situation literally "on the fly". I guess it's this individual act of setting our personal risk tolerance that may dictate whether we want to have the option to mess with a CB, or to let the fuse have the final say.

I was doing some IFR training in my RV-10 last summer and the instructor felt that the decision I made for blade fuses was questionable. After I explained to him that if a problem developed to trip a fuse in flight, it was time to land, diagnose and fix the problem. No different than if using a CB. That made him think a little.

I was a passenger in an aircraft years ago when acrid smoke started pouring out of the transponder. Switching it off didn't seem to help so we found the breaker and pulled it. This was a day VFR flight and we were only about 2000' agl, but it was scary how fast the cabin air became unbreathable and we would not have survived long enough to land the airplane had we not been able to isolate the source of the smoke. Imagine a situation like this in IFR where you depend on the panel to keep you upright and navigate to your destination. Hitting the master switch will probably stop the smoke, but that isn't always a viable option.

The point is that you need some way to remove power from a specific piece of equipment. Even a readily accessible fuseblock can be difficult to label clearly in a large enough font to read in all lighting conditions (not to mention with smoke in the cockpit), and fuses can also be difficult to pull with your fingers. If you pull multiple fuses and then need to restore some of them, you've got to sort out which size goes back in which slot. There are a couple alternatives to this problem. One is to use toggle switches along with fuseblocks, and the other is to use CBs.

In my RV-8A I added toggle switches along the right side console to control power so I could turn things on/off without touching the fuses. But then you've got to install fuses AND toggle switches to do the same job that you can do with circuit breakers. So there's a good argument for using accessible, clearly labeled breakers.

Downsides of breakers are cost (they tend to be more expensive than a fuse + toggle switch), if you use them a lot to turn off non-essential stuff on the ground (like your autopilot while you're loading databases into your EFIS) you can wear them out faster than a toggle switch, and if you really need to turn something off fast a toggle switch is easier than pulling a breaker. I had a double pole toggle switch with one pole controlling power to my trim system and the other to my autopilot. If the flight controls start doing something I don't like or expect (which may be accompanied by rapid build-up of G forces in some malfunction scenarios) I can hit the toggle switch and kill power to all that stuff quickly and easily. Another downside to breakers is that they are mechanical devices that are less reliable as circuit protection devices than a simple fuse. Some older aircraft have a CB that is glitchy and will occasionally trip (and need to be reset) even if there's nothing wrong with the circuit...it's the CB itself that is the problem.

I still haven't decided what I'll do on my -14. I'm leaning toward fuseblocks with power switches on the right side of the panel, but it's more work to install and wire than a breaker panel.

A few additional thoughts/comments......

Pretty much standard in all RV's (as well as most other gen av aircraft) is an electrical system with a master contactor.
ANY electrical issue (smoke building in the cockpit, etc.) that requires immediate remedy warrants shutting down the electrical system with the master. If you are IFR you should be in an airplane that has alternate power back-ups so that master off should not be a problem. If you say you NEED to keep power on because you need the autopilot... you probably shouldn't be flying IFR.

If there is smoke in the cockpit it likely means you have a problem that neither circuit breakers tripping or fuses blowing has resolved, so the only safe remedy is removing all power from the electrical buss by switching the master switch off.

Fuses are more reliable than circuit breakers...... I have never heard of a fuse not blowing in a short circuit situation as long as it was properly sized for the wire in the circuit.
There have been instances of circuit breakers NOT tripping in a short circuit situation. Some have cause accidents.

Fuses are lighter than circuit breakers

Fuses are way cheaper than circuit breakers

With proper system design, a fuse can be pulled just as simply as a circuit breaker.

Fuses can save stupid pilots from themselves...
I have heard of people repeatedly (dozens of times) resetting a circuit breaker in order to complete a flight.
Hard to believe, but I have even heard of pilots having passengers hold a breaker in the on position because they were convinced it was a defective circuit breaker.
This would never happen with a system containing fuses.
Sure, there is nothing to prevent someone from putting in a bigger fuse (you can't prevent all stupidity).

I?m with Mark on this one and I?m designing my panel with switches and fuse blocks. My IFR panel will account for loss of systems and if a fuse blows there?s likely a reason it did so. I don?t like the idea that a CB blows I reset it and go back to relying on equipment that has a higher than normal potential to fail again at a more critical point in flight or produce an emergency such as smoke in the cockpit. I?d rather rely on my standby equipment and dig into the problem on the ground. Bob Nuckolls gives a pretty good argument for the use of auto fuses in his book as well.

Well first of all let me say I'm planning on fuses for my plane. I picked them because they are cheaper and sufficient to do the required job. If you use a fuse block then they are more convenient to wire up.

The main item I see with fuses is they have to be properly sized. Now normally a short results in quite high currents and the fuse or circuit breaker will open up. Fuse can't be reset and neither can a circuit breaker unless it was improperly sized.

The two example stated previously don't seem to be valid examples of reasons to need circuit breakers..

How was it possible to short two wires in flight that were critical? Just looking at the facts here maybe that wasn't the best build selection for flight and circuit breaker doesn't make it a better decision. Fumbling for the correct fuse shows a lack of understanding in this area. Most of the fuses would have fixed the immediate problem I suspect.

Example 2 doesn't seem like a good validation for the need for a circuit breaker either. If the power switch didn't turn off the smoking transponder then obviously there was some wiring problem. Adding a circuit breaker wouldn't by itself fix that. Was the insta?led fused actually sized correctly?

There always seems to be a lot of folklore that goes along with these types of things but mostly it's tends not to be based on facts. I don't fault those you don't understand and everyone can do whatever they want in their plane. I even think a couple hundred dollars worth of breakers looks cool but providing real additional functionality for most uses is limited in my opinion. The ability to remove power if desired is probably the only one.

Just my 2 cents and you can do whatever makes you feel comgortable.

Truth of the matter is that electronic circuits fail. Wires fail, connectors fail, electronics fail and they do so in all phases of flight. Mostly they fail open or shorted but they can fail in more insidious ways. The point is you should count on system failures and build that into your aircraft design. Both CB and fuses can provide good methods for protecting wires. However, the original comment that someone was nervous about fuses was unfounded and it seems good to point this out to other builders. Dan H?s question was a good one.

rvbuilder2002 said:

ANY electrical issue (smoke building in the cockpit, etc.) that requires immediate remedy warrants shutting down the electrical system with the master.

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Just to clarify with respect to my experience with the smoking transponder, in that case it was obvious that the transponder was the source of the smoke and there was an easily accessible, clearly labeled breaker for it, so the pilot pulled the breaker. I would agree if there's smoke in the cockpit and it isn't immediately clear where it's coming from or there isn't a quick way to remove power from only the offending unit, the correct action is to kill the master switch.

rvbuilder2002 said:

If you are IFR you should be in an airplane that has alternate power back-ups so that master off should not be a problem.

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Agree you should have something that can keep you from losing control of the aircraft after turning off the master. In the old days this was a vacuum gyro. Nowadays it's typically a standby instrument with its own built-in battery (and hopefully that battery isn't the source of the smoke!). But think about the situation where you're in IMC, you have smoke in the cockpit, so you hit the master switch. You're now hand flying on a small attitude display. You've lost com, transponder, GPS, moving map, IFR flight plan, autopilot, engine monitoring, etc. You don't want to be in that situation for any longer than you have to, and your chances of getting out of it alive are much better if you can get more of your panel back. If you have accessible breakers or power switches for all of your avionics, you can turn them all off and then turn the master back on. If the master alone starts making smoke again you've got no choice but to stay on your standby and any handheld backups (or try the E-bus if you have that architecture). Most likely turning the master back on doesn't make any smoke and then you can start turning the most essential equipment back on one thing at a time. This allows you to get some of your panel back in a methodical fashion and may also clarify the specific source of the smoke so you know what to leave off for the remainder of the flight.

In the same scenario if all you've got is fuses, after shutting off the master you'd have to pull out every fuse, turn the master back on, and then reinsert the fuses one at a time (making sure to get the correct size fuse in each slot). Much easier to work through this scenario with breakers or toggle switches.

rvbuilder2002 said:

With proper system design, a fuse can be pulled just as simply as a circuit breaker.

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I partially agree. Maybe it depends on the specific brand of fuses and fuseblock, but I have sometimes found it difficult to grasp and pull a fuse located between two other fuses. For me pulling the CB is a bit easier, but the most important thing is accessibility and clear labeling (to your point about proper system design). There's a tendency to hide fuseblocks out of sight (because they aren't exactly beautiful to look at and you shouldn't need to change them in flight anyway...if a fuse opened, it's almost certainly for a good reason that should be addressed on the ground). The problem arises if you need to remove power from something and you're fumbling around under the panel to find the right fuse.

rapid_ascent said:

Example 2 doesn't seem like a good validation for the need for a circuit breaker either. If the power switch didn't turn off the smoking transponder then obviously there was some wiring problem. Adding a circuit breaker wouldn't by itself fix that. Was the insta?led fused actually sized correctly?

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I don't know why turning off the power switch didn't stop the unit from smoking...it's possible that it would have and we just didn't wait long enough (whatever was smoldering inside would not immediately stop after turning off the switch on the unit). Regardless, many modern avionics units don't even have a physical on/off switch. My point about the CB is that it was an easy way to physically remove power from the transponder. You could also do this with a fuse IF it's easy to find, clearly labeled, and you can grasp it hard enough with your sweaty fingers to pull it out. A panel mounted CB or power switch is typically easier to turn off...and just as importantly, if you've had to turn off multiple LRUs (because you're unsure of the source of smoke) they are easier to use when restoring power than having to put the right size fuses back into the correct slot.

With respect, the smoking transponder anecdote isn't an argument for a breaker.

If a panel device really is shorted, internally or feed, any correctly sized circuit protection device will disconnect it without pilot intervention.

Even if it is necessary to manually disconnect a device, there's no reason to pull all the fuses or breakers when the faulty device has been identified. Poor accessibility or poor labeling of a fuse or breaker is a design problem, not a circuit protection problem.

Given an unidentified smoke source which did not automatically trip/melt the circuit protection, we would open the master switch. However, in today's typical EAB there is no reason to re-engage the master in order to obtain fundamental flight and nav guidance. These days most of us install the EFIS and GPS with (a) individual battery backup, or (b) an isolated alternate power feed. Master OFF in my VFR airplane requires no pilot action to maintain EFIS and GPS. A current spec IFR EAB is generally just E-bus ON, then Master OFF. Flip, flip, done.

Let's return to the original question. Why does a fuse make some builders uncomfortable? We know the power of familiarity (familiar = comfortable). Is it a career spent drilling emergency procedures in complex aircraft?

Comfort aside, is there an engineering reason, i.e. specific evidence that says an ordinary ATO/ATC blade fuse is less reliable than a breaker? Is there a specific need with some particular circuit, perhaps to lengthen the trip time, or because a required test trips the circuit protection?

Please note: I'm not opposed to circuit breakers. They are simply one of several possible choices for circuit protection. We should install the lightest, most reliable circuit protection device that will reliably meet all requirements. Although I hear and understand the human factor ("It makes me feel better"), it is not an analytical approach to design.

An additional note.

There are breakers available that fit into an ATC fuse block slot. There are several different kinds. I have a couple that are resettable, a small tab pops and can be pushed back in to reset. I use them in a fuse block for the alternator field wires with the rest being regular fuses.

When you design your panel, if you have a need or want to turn something on or off you should not depend on pulling a fuse or breaker. That calls for a switch.

If you want to easily pull a fuse, buy a fuse puller when you buy your fuses and velcro it next to the fuse block. Makes it easier to pull a fuse than pop a breaker. It should also not be any harder to locate a fuse in a well labeled fuse block than trying to find the right breaker in the pictured panel at the top of this thread. There are 30 tightly spaced breakers there.

Like others have said, turning off the master should be a mostly non event. I'm fine with breakers but find fuses much easier to work with.

Wow

I didn't expect to open such a dialog on the pros and cons of fuses vs circuit breakers. I am definitely not an electrical expert but I can give MY reasons for going back to circuit breakers. Reason #1: Both me and my builder assist felt the fuse panel felt somewhat flimsy in it's construction. Auto type fuses are designed for automobiles with far less vibration and stress than aircraft. Reason#2: Since my wife will be doing most of the long cross country's, we didn't want her getting stuck at an airport where certified A&P's may refuse to work on something they are not familiar with. Reason #3: I needed to pull a fuse to test whether or not a circuit was getting power. I did have some trouble as I have large hands and wasn't able to get a grip on the fuse without going to my car and getting a fuse puller (supplied in the fuse box of our Hyundai). My first impression when I saw the new breaker panel was how robust the construction seemed in comparison to the fuse panel. As others have stated, it is all a matter of choice. As for the pricing, Stein told me that both units, comparing the same configurations, would be about the same expense. Thanks for all of the response guys.

I am a product of the instant gratification generation. I like things easy. I do not want to have to keep and maintain a kit of spare fuses that I hope are in my flight bag when that one fuse 'pops' because I was tinkering with something during a fuel stop in a small town. I dont want to hope there is someone on the ramp that has a 3A fuse in the style I need and I dont want to hoof it to the local auto parts store to find the fuse I needed.

I want to push the breaker back in and remonstrate myself for fiddling with my electronics at a rural airport. Easy peasy.

Having rented several Cessnas and Pipers I have a plastic container of the various types and sizes of fuses that I used to carry with me for just this occurance. Nevermore.

woodmanrog said:

My first impression when I saw the new breaker panel was how robust the construction seemed in comparison to the fuse panel.

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Robustness (particularly if it is not needed) always comes at a cost.

Did you happen to measure what the weight difference of the two was?

I think what some of us are trying to point out is there is a difference between a desire to use circuit breakers and a need to use them. I personally have nothing against them. My concern is on these types of open forums where there is a need expressed and there are builders that are less knowledgeable in electrical wiring and etc. who might get the impression they are in fact needed.

czechsix said:

But think about the situation where you're in IMC, you have smoke in the cockpit, so you hit the master switch. You're now hand flying on a small attitude display. You've lost com, transponder, GPS, moving map, IFR flight plan, autopilot, engine monitoring, etc.

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If this ended up being a real scenario, I would say the person who designed the panel/systems didn't do a very good job.

I wouldn't much care about loosing the engine monitor (though in most of the battery backed up EFIS that are currently popular, you wouldn't).

If the system is designed the way it should be / could be, there is no reason to have flight critical equipment unavailable, unless it is connected to circuit that is causing the electrical problem (I don't consider a transponder and auto pilot to be flight critical... if you can't manage without those, you probably shouldn't fly IFR)

czechsix said:

There's a tendency to hide fuseblocks out of sight (because they aren't exactly beautiful to look at and you shouldn't need to change them in flight anyway...if a fuse opened, it's almost certainly for a good reason that should be addressed on the ground). The problem arises if you need to remove power from something and you're fumbling around under the panel to find the right fuse.

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Yup!
Like I (and you) have both said, it is all about proper design.

My personal RV-6A has a hidden fuse panel, but it hinges down into view at the bottom of the instrument panel with a turn of one winged camlock fastener.
I can easily reach it from the pilot seat and a passenger can even more easily access it for me.

DanH said:

With respect, the smoking transponder anecdote isn't an argument for a breaker.

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Doesn't have to be a breaker, but it's an argument for a means of isolating power to a specific piece of equipment. It could also be done via a power switch (my personal preference) or an accessible, clearly labeled fuse.

DanH said:

If a panel device really is shorted, internally or feed, any correctly sized circuit protection device will disconnect it without pilot intervention.

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Keep in mind that the circuit protection device is sized to protect the wire that feeds power to one or more devices. This does not guarantee that the panel device doesn't have internal components that could generate smoke without exceeding the rating of the circuit protection device.

DanH said:

Even if it is necessary to manually disconnect a device, there's no reason to pull all the fuses or breakers when the faulty device has been identified.

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If you read my previous post more carefully, I was not suggesting that you should pull out all the fuses or breakers if you've identified the faulty device.

DanH said:

Given an unidentified smoke source which did not automatically trip/melt the circuit protection, we would open the master switch. However, in today's typical EAB there is no reason to re-engage the master in order to obtain fundamental flight and nav guidance. These days most of us install the EFIS and GPS with (a) individual battery backup, or (b) an isolated alternate power feed. Master OFF in my VFR airplane requires no pilot action to maintain EFIS and GPS. A current spec IFR EAB is generally just E-bus ON, then Master OFF. Flip, flip, done.

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I like and advocate the use of an E-bus architecture, but if the source of the smoke is a piece of equipment on your E-bus, then you haven't eliminated the problem by flipping off the master and turning on the E-bus.

DanH said:

Please note: I'm not opposed to circuit breakers. They are simply one of several possible choices for circuit protection. We should install the lightest, most reliable circuit protection device that will reliably meet all requirements. Although I hear and understand the human factor ("It makes me feel better"), it is not an analytical approach to design.

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With respect Dan, I have to disagree with your last statement. In my professional career I have been guilty of not fully considering the human factors of a design and learned that if a design fails because of inadequate human factors design, it has failed just as surely as if it had insufficient structural strength or inadequate circuit design. While I agree that fuses provide adequate circuit protection in an aircraft, human factors issues that have been described above were central to my decision to use circuit breakers in my RV-9A. No, I have not yet built the panel, but this decision was made a long time ago for reasons that still make sense to me.

An analytical approach to design considers ALL factors and weights them according to their importance.

My fuse panel is not accessible in flight. Every electrical item can be disconnected with a switch or relay. I carry a very short handful of spares that weigh nothing.

Coming from the electrical industry, I have a very poor opinion of circuit breakers. If you care to look at the breaker specifications and their tolerances, it might surprise you. A bimetallic strip heating up to trigger a spring loaded mechanical device is pretty Rube Goldberg'ish if you think about it.
I have never seen a fuse fail, ever. I have seen several circuit breakers fail, including one in my commercial office bldg. that nearly burned the place down. However, over the course of my 32 years in the industry, it has been a scant few. The odds of a catastrophic breaker failure is probably really, really, slim.

Just another data point for those contemplating. I am a fuse guy.

This is the elctrical version of the primer wars.

The bottom line is that I tell everyone to build THEIR airplane they way THEY want it. It is their airplane. There are advantages and disadvantages to both systems.

As for me, I have been using the fuseblocks since as long as I can remember, and have at least 4000 hours flying behind them. As mentioned many times, a properly sized fuse never needs replacing. I check for proper seating at all inspections or whenever the panel is open, and I'v enever had one need to be replaced, or come loose and cause a failure.
I actually get tired of carrying around all of the spares to meet the regs for night flight.

For those wanting an indication of a blown circuit with fuses, there are illuminated blade fuses available. They have a small led built into them that turns on when the fuse blows. Bussman makes some. I think they call them easyid.

ksauce said:

For those wanting an indication of a blown circuit with fuses, there are illuminated blade fuses available. They have a small led built into them that turns on when the fuse blows. Bussman makes some. I think they call them easyid.

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Correct.

They are standard equipment on the RV-12 and RV-14(A) fuse panels.

I have had a CB blow for my flap switch a couple of times because I forgot to turn it off in the retract position. I know I need to add a micro switch cut off... but it was easy to restore flap power once I realized. I like CB's.

There are several assertions that fuses have a low failure rate. After a few decades in the avionics trade I can assure you that I have seen fuses fail. They generally fail open-circuit, but still they fail. I have seen too many aging Brand B, C and P aircraft that have corroded fuse holders. I have seen fuses that visually look perfect, but have had one end of their fuse material vibrate loose from the end cap. It can, and does happen. The newer automotive fuses are, I believe, vastly superior to the old glass cylinder ones.

Still, I have had two fuses fail in my current vehicle. Yes, both were open circuit, and neither was "blown", both failed mechanically.

Earier this year I was called upon to diagnose to separate avionics problems in two different aircraft. Both of them ended up being faulty CB's. Nothing is perfect.

THE biggest lesson in this entire discussion is the one focused on the absolute need to fully review the design of our electrical systems, and then get a few other sets of eyes to conduct independent reviews to ensure a broader perspective is applied. It is very easy for us to get tunnel vision when we design things - a fresh set of eyes may catch a potential failure mode that we had never even considered. (Written by a guilty party - I've pulled some pretty boneheaded moves and have been spared the embarrassment of a cloud of electrical smoke a couple of times when folks wiser than I took a moment to point out the error of my ways!)

Steve Melton said:

I have had a CB blow for my flap switch a couple of times because I forgot to turn it off in the retract position. I know I need to add a micro switch cut off... but it was easy to restore flap power once I realized. I like CB's.

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My flap switch is momentary. I thought that was standard, or at least Vans standard. I wouldn't accept operator error as a good reason to use a breaker or a fuse. I would fix the problem as neither should open or trip.

JonJay said:

My flap switch is momentary. I thought that was standard, or at least Vans standard. I wouldn't accept operator error as a good reason to use a breaker or a fuse. I would fix the problem as neither should open or trip.

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yes, that's on my to do list for the Winter.

I remember another time I had a CB trip, it was 6 months ago, my cigarette lighter became loose and shorted. I use it to power my GDL39. I was somewhere over NM. I was able to temporarily position the cigarette lighter to a non shorted position and power it back up. Now the cigarette lighter clamping ring is secured with loctite.

Great thread! I really enjoy the differing perspectives on what works for each plane/pilot.

I've considered this, too. Fuses, breakers, VP-X type active breaker systems. It's alot to think about.

All these have some merit, but as a relatively conservative pilot, I believe if a breaker blows (VP-X type or conventional), that's a sign of a serious problem with the electrical system. I don't have confidence that simply resetting a breaker will "fix" the problem, though it might mitigate it for a while until the over-current condition comes back.

My current plan is to go with properly sized fuses (I do like the ones that light up when blown), and do any troubleshooting on the ground if they blow. The master switch is the ultimate shutdown for the electrical system (I'll be using two conventional mags) should a fuse not blow when it should. I'll have other switches to isolate critical systems that might go crazy, like the auto pilot, but if a fuse blows, it stays blown until I can get down and diagnose the problem.

My electrical system will use standard fuses to protect the electronics and wiring. Cheap; reliable; light; proven.

I've never had to change a fuse in any of my cars over all the years of operation. If one ever did blow, I'd ask "why in the heck did that blow?" and find the root cause of the issue before replacing the fuse.

I'm very comfortable with fuses, it seems the right solution for me.

wjb said:

Great thread! I really enjoy the differing perspectives on what works for each plane/pilot.

"xxxxx.... seems the right solution for me.

Click to expand...

Whatever you do in your airplane, the "seems the right solution for me"... is key. As others have stated, build the airplane you want. Make it safe, reliable, and work for YOU!
This whole thread started by the OP stating they where uncomfortable with a solution, whereby the question was asked "why?". Good civil dialog followed.... No right or wrong answer, but there where a few reasons for one choice or another that simply where not based on good reasoning or fact, along with a lot of good information for those pondering the decision.

Good stuff can come out of a simple statement, question, and thought.

Both fuses and breakers

Form my first avionics planning, I felt the yin & yang of fuses (what Van has designed into the 14) and circuit breakers (tradition plus some other utility). I decided to go with a hybrid set up. For those items for which I want either occasion switching or reset-ability, I am putting a switchable circuit breaker on the panel (every Garmin box without an on/off switch, autopilot servos, P-mags, etc). For all others, I am using fuses, many with switches (like lights, pump, etc). I have selected those items I want to be resettable (breakers on the panel) and those I will not reset (fuses - and the fuse panel is not planned to be accessible in flight). The result is a more complex bus and wiring structure (such as two connected main busses - one for SCBs and one for fuses), but I feel I am getting the best of both with an acceptable increase in complexity. Not better or worse, but right for me. Ah ... the beauty and pleasure of experimental aircraft.

In the spirit of Dan's post in another thread asking for pictures of good baffle seals, I would love to see pictures of intallations with a well designed fuse panel, especially the easyid fuses.

During my build I would be repeatedly badgered about "what do you need THAT for?" with anything another builder thought was too "fancy". I finally figured out the response: " what do you NEED an airplane for? You don't, but you want it so badly that you're willing to devote time and money to build the airplane you WANT!"

For me, a lot of what determined my comfort level was if I understood it and if I had seen good examples of it to emulate. I have circuit breakers now, but will probably be doing a panel redo as the 2020 mandate gets closer and I'm all for learning and getting comfortable with all the options.

So...let's see some photos of good examples of easyid fuse panels, with bonus points for one of the fuses showing a blown fuse

Good design? Well, hmmm, this probably won't apply, but you asked.
This was a retrofit. If you have a clean slate, you can do better.
I utilized an abandoned autopilot controller location under the panel. In my scrap aluminum bin I found the remnants of an old style RV6 battery box. Nut plates already there from autopilot. Rigid base for fuse blocks and terminal strip. Perfect!
After discussions with Stein, I elected to mount the assembly face down! Yes. Face down. No. The fuses will not fall out. No. Our application is not more severe than an automobile, in fact, probably much less harsh and certainly much less severe than some of the race car or 4x4 truck world. 400 plus hours of running this set up and the fuses are still tight and haven't moved. They aren't going too. Mounting it upside down has one big advantage; nothing can fall into it to get shorted. You don't need a cover.
Rather than use large wire for the buss, I chose to tin a chunk of copper. I probably could have done without the terminal block, but I wanted it there for future. The third fuse block is fed from a control relay allowing me to isolate it for future consideration. Labeling is a problem. I carry a sketch of the layout in my POH.
Simple, stupid, and straight forward. I don't understand the need for a visible fuse indicator. The symptoms will tell you what fuse it is and you need to fix the problem anyway, in my case, that will be done on the ground. This picture was taken without the final fuses installed.
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