Looking for input...I'm clueless

A place to discuss the design & installation of electrical systems.
Dan A
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Post by Dan A »

If you do use a fuse block, be sure to have it accessable from your pilot position as you may need to be changing fuses in flight and at that point it would not be fun to try to crawl under the panel! I went with the c/b's because I do not like to carry extra fuses and try to change them when I need the circuit. I had the flap motor breaker trip on me once and it was resetable after a short time. Saved me a hot landing. Lowering the flaps at too high a speed can, and will, blow a fuse or trip a breaker.Good luck which ever way you go.
Dan N742DA

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rob
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Post by rob »

Is that really a good idea, Dan? I would say that 99% of the time, if a fuse blows or a CB pops, there is a good reason for it. The last thing I will be doing is monkeying with fuses in flight. I have heard way too many times about pilots that hold in a popped breaker to make the flaps come down, or something similar. Seems like a really good way to start a fire to me...
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cjensen
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Post by cjensen »

I haven't decided on the fold down fuse block, but I probably won't worry about it. My airplane is pretty much ALL manual (including the flaps), and I don't really have anything in the airplane that I would worry about resetting in flight if I blew a fuse.

I certainly appreciate the suggestion, but I can't figure a reason to make it apply to the flying I'm gonna do... :)
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weezbad
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Post by weezbad »

rob wrote: I would say that 99% of the time, if a fuse blows or a CB pops, there is a good reason for it.
i wouldnt give it marks no where near that high. if a main breaker pops, Avionics for instance, i can pull all the breakers turn on the main breaker and start adding back items while watching tha amp meter. you guys can and will do as you wish but i want to have back as much instrumentation as possible. no radio, no lights, no instrumentation, no flaps, no trim, not to mention my ipod :lol:
all jokes aside in the event of an emergency c/b's are the only way to go. fuses are for cars. circuits breakers are resttable for a reason. flame suit on. 8)

i wouldnt reset it unless i had to.
william....don't let it beat you down, you are stronger than you think.

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Brantel
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Post by Brantel »

Thats why you do a fuse for everything and make sure you coordinate the system to ensure that a fault on a sub circuit does not take out any parent fuses.

Nothing wrong with either approach but the fact remains that fuse blocks and fuses are way cheaper upfront and also take tons less time to install and if done properly will provide equal to superior protection and are just as functional in the real world.

There is absolutely no way that I would reset a breaker in flight unless I could determine the reason it popped. You are asking if not begging for a fire if you do this.
Brantel (Brian Chesteen),
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bullojm1
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Post by bullojm1 »

Ah the Fuse vs Circuit Breaker great debate....I think this is one of those touchy topics just like Primers and tailwheel vs nosewheel.

Instead of arguing which way is better, I'd like to hear from people who have had breakers pop in flight and what their cause is.

In my vast 150 hours of flying airplanes, I have only had one circuit breaker fail - the alternator CB in a 172. I DID reset it and all was well. It never tripped again after that flight.
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rob
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Post by rob »

weezbad wrote:
rob wrote: I would say that 99% of the time, if a fuse blows or a CB pops, there is a good reason for it.
i wouldnt give it marks no where near that high. if a main breaker pops, Avionics for instance, i can pull all the breakers turn on the main breaker and start adding back items while watching tha amp meter. you guys can and will do as you wish but i want to have back as much instrumentation as possible. no radio, no lights, no instrumentation, no flaps, no trim, not to mention my ipod :lol:
all jokes aside in the event of an emergency c/b's are the only way to go. fuses are for cars. circuits breakers are resttable for a reason. flame suit on. 8)

i wouldnt reset it unless i had to.

Weez -- I would say in this instance that if a single breaker took out the entire avionics stack, then that is the case of a poorly designed electrical system. Like Brian said, each item should basically be on it's own circuit, not gang'ed together...that is just asking for a situation like you describe where one failure takes out many things. On my plane, there is no single point of failure that can take out all instruments. Even with a primary battery failure, I have backups on my EFIS and my autopilot. I'd never depend on the backups solely (and I will be VERY dilligent about replacing them), but they are there just in case.

And no, I wouldn't say this is a fuse vs. cb debate -- i think it is a debate on whether or not one is a gambler with an in-flight electrical fire. May just be me, but I'm not gonna roll those dice....
Rob Johnson
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tmbg
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Post by tmbg »

bullojm1 wrote:Ah the Fuse vs Circuit Breaker great debate....I think this is one of those touchy topics just like Primers and tailwheel vs nosewheel.

Instead of arguing which way is better, I'd like to hear from people who have had breakers pop in flight and what their cause is.

In my vast 150 hours of flying airplanes, I have only had one circuit breaker fail - the alternator CB in a 172. I DID reset it and all was well. It never tripped again after that flight.
and I'd be willing to bet that it was the first flight after jumpstarting the airplane cause the battery was dead, no?

That's a pretty common thing to have happen on certified birds... they have a 60 amp alternator and a 60 amp breaker, but the alternator can actually put out a LOT more current than that, and the battery WILL ask for it if it's completely dead.

Nuckolls has some better ways to handle that scenario.
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bullojm1
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Post by bullojm1 »

tmbg wrote: and I'd be willing to bet that it was the first flight after jumpstarting the airplane cause the battery was dead, no?

That's a pretty common thing to have happen on certified birds... they have a 60 amp alternator and a 60 amp breaker, but the alternator can actually put out a LOT more current than that, and the battery WILL ask for it if it's completely dead.

Nuckolls has some better ways to handle that scenario.
Actually, no, I was running the plane all day - popped right before the 4th landing. I know Nuckolls has a better way, and I fully plan to put the ANL current limiter in (in fact, its on it way now from B&C!).
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N941WR
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Honest, I didn’t mean to start this argument again…

Post by N941WR »

Honest, I didn’t mean to start this argument again…

What I was trying to point out that if you go with fuses (there is nothing wrong with them), don’t hide them up where you can’t get to ‘em w/o laying your back and working with a flashlight and a mirror, which is exactly what is going to happen if your attach them vertically to one of the ribs forward of the panel.

As your airplane matures and you start adding equipment, you will want access to that fuse block. Not only that, but fuses can be defective and blow prematurely, or more accurately, break. I’ve seen this happen in cars, old and new. A fuse pops and there is nothing wrong with the circuit other than a bad fuse.

For the record, I also had a CB-switch go bad on my RV. One hot day I left the canopy closed and when I got in the plane, I couldn’t turn on my fuel pump. Once the thing cooled down, the pump’s CB-switch worked fine. I simply replaced the CB-switch and haven’t had a problem since.

There is nothing wrong with using fuses, just make them accessible.

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Post by weezbad »

rob wrote:
weezbad wrote:
rob wrote: I would say that 99% of the time, if a fuse blows or a CB pops, there is a good reason for it.
i wouldnt give it marks no where near that high. if a main breaker pops, Avionics for instance, i can pull all the breakers turn on the main breaker and start adding back items while watching tha amp meter. you guys can and will do as you wish but i want to have back as much instrumentation as possible. no radio, no lights, no instrumentation, no flaps, no trim, not to mention my ipod :lol:
all jokes aside in the event of an emergency c/b's are the only way to go. fuses are for cars. circuits breakers are resttable for a reason. flame suit on. 8)

i wouldnt reset it unless i had to.

Weez -- I would say in this instance that if a single breaker took out the entire avionics stack, then that is the case of a poorly designed electrical system.
i would have to respectfully disagree with that. you are making the assumption that incorrect values have been used to determine system loads. in that case you would be right. all of the fuse users should know that all modern cars have Maxi fuses (typically several 30-40 amp fuses under hood in the convienience center) feeding down to mini fuses in the interior fuse panel feeding individual components. the reason i have a avionics master c/b is to protect the wiring feeding the avionics master switch.(another single point of failure) in the event of a short prior to a c/b (or fuse in your case) mine is still protected. i protect the supply then i protect the component. that is what i call redundancy but TEHO. i suppose you will never have a failure on the hot feed to your fuse. for the record i would use either, i do like c/b's better because all of the nice airplanes and helicopters ive been in have banks of them. and it looks cool when i pull them all out then take someone for a ride. i can flip switches and push buttons like im in the space shuttle. they think wow this is really complicated you must be really smart. :lol: anywho, im sure that most everyone here, just simply by being here and spending the time researching and planning is many a step ahead of the avaerage builder. got an air show to go to maybe i'll see an rv. 8) ya'll have fun...later
william....don't let it beat you down, you are stronger than you think.

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jakec
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Post by jakec »

I must have something like 60 C/Bs in the helicopter I fly (OH-58D) and it seems as though not a flight goes by that I do not have to re-cycle a circuit breaker or two. I'll get a failure of a subsystem like a radio, transponder, GPS, weapons system, etc and many times simply pulling the breaker and popping it back in is enough to get it going again. Granted, I’ll think long and hard before popping in a breaker that popped on its own.

I think the flexibility of being able shut down individual components to either troubleshoot system failures or reduce the power load during an alternator failure might be handy. When you use fuse blocks do you have that ability?

Please take my comments for what they are worth. My experience may not directly correlate to good general aviation practices. The OH-58 is a cobbled together Frankenstein of an aircraft (but boy I sure love it) and troubleshooting is an everyday thing for me. God knows I don't want to create an issue or problem where there is none. Simple is good.
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weezbad
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Post by weezbad »

jakec wrote:I must have something like 60 C/Bs in the helicopter I fly (OH-58D)
The OH-58 is a cobbled together Frankenstein of an aircraft (but boy I sure love it) and troubleshooting is an everyday thing for me. God knows I don't want to create an issue or problem where there is none. Simple is good.
i mostly worked on A and C models of the OH 58.. they kept the d models across the street at the 5th special forces unit. those thing looke like they were on steroids. do they still let an enlisted man co-pilot them? i think they called them aero scouts when i was in.

most of the fuse panels in rv's are inaccessible in flight, but then 99% of most components are switched so you should still be able to conserve power if need be.

thank you for your contribution to our country.
AERO SCOUT.....SOLDIER ONNNNNN
william....don't let it beat you down, you are stronger than you think.

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jakec
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Post by jakec »

do they still let an enlisted man co-pilot them? i think they called them aero scouts when i was in.
Nope. Not any longer. Just Warrant Officers and above unfortunately. Sometimes I'd rather have an EM next to me! Thank YOU for your service Wheez!

As for the switched components....that is good. A lot of the panels I've seen lately don't seem to have much in the way of switches. Then again, maybe I miss them because I can only look at a panel for about 5 seconds before I pass out when I remember how much it's going to cost me some day...

Chad, you and many others on here are my inspiration.....keep it up bud!
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Brantel
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Post by Brantel »

weezbad wrote:
jakec wrote: AERO SCOUT.....SOLDIER ONNNNNN
weez, were you one of those lucky Scout's that got to go thru flight school? If so, did you go thru the whole program or just a subset?

I tried to get that MOS when I went in but flunked some sort of "stereo fly" eye test and they disqualified me on the spot.

Have no idea what that test was but I have always had 20/20 vision and no other problems. Never had that test in the civilian world so I have no idea what it was.
Brantel (Brian Chesteen),
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Post by weezbad »

oh man i wish, i didnt find out about it until i was at Ft rucker. they seemed to have more interest in soldiers that were already established in the army for that option at the time. :cry: i wanted to fly, and blindly joined to be a mechanic :lol: :bang: . get this, my recruiter tried to talk me out of it. i grew up in a little town and anything would have been better than staying there..my brother was in the military and my dad was retired ARMY, seemed like goin home to me. :oops: now i cant imagine leaving this little town.:? my wife tried to talk me into GA :o but i told her "they dont have guns and rockets on cessnas" :P 15 years later my brother say's "hey man im building a plane" 8) i looked at the factory plane on vans and thought man that is sweet...just wish i had gone tailwheel. the rest is history.

sorry to hijack your thread Chad..
Last edited by weezbad on Sun May 25, 2008 8:03 pm, edited 2 times in total.
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cjensen
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Post by cjensen »

jakec wrote:Chad, you and many others on here are my inspiration.....keep it up bud!
Thanks buddy! Will do! You keep it up too!! 8)
Chad Jensen
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cjensen
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Post by cjensen »

weezbad wrote:...just wish i had gone tailwheel.
All it takes is time and some parts!! :lol:
weezbad wrote:sorry to hijack your thread Chad..
Not a problem...all good! 8)
Chad Jensen
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