fuses v circuit breakers

[WildBill]

http://www.ntsb.gov/ntsb/brief.asp?e...12X18177&key=1

[Norman CYYJ]

If you have deep pockets circuit breakers are the way to go, if your pockets are even deeper use circuit breakers that you can pull off and for really deep pockets use toggle circuit breakers. But all joking aside fuses are more reliable, less weight and much cheaper. I guess Van's and Piper and Cessna go to breakers for convienence and a modern look. What ever way you go you are protecting the wire to a device, not the device itself.

[Captain_John]

George, I gotta say... I think we (and I mean everyone) are all pretty much on the same page here with all of our thoughts. This is a good thing.

I am not always "on board" with the new designs. Especially the new AFCI's. I am a traditional Yankee and new things are not immediately embraced by me. I take a wait and see attitude ALOT. With regard to the way these types of things make it to market are not to my liking. I have a verbal tirade about this which is too long and too far OT to go into here. If you care to chat about it, www.skype.com me sometime and we can chat.

The AFCI's were NOT WITHOUT their problems when initially introduced and can very easily nuisance trip or not serve their purpose when needed. If that is the case, I prefer NOT to use them. We are being REQUIRED to install them in residential occupancies now and I am sure that they will follow the way of the GFCI's being required in more and more locations as supplies and laws increase in magnitude.

Tony, very nice drop down panel! I will implement a similar feature!

CJ

[jlfernan]

There's been a lot of debate between CB's and fuses and all that it's done is confuse me even more!! No one has yet mentioned(except me many posts ago) switch breakers. They're more costly, but seem to free up plenty of room. Someone, anyone, please chime in with your opinion of these.

[Yukon]

Jorge,

Switch breakers are good too, and are used extensively by Van's. They are expensive, and don't offer the redundancy of a switch and a CB for turning off a circuit. The good news is, they aren't hidden out of sight like most fuse panels.

Take a look at Kahuna's post about the desirability of isolating the BMA and
GR for software re-boot. Ask the guys promoting fuses if that can be done with their system.

[jcoloccia]

The only issue with switch breakers is that if you want to use it as a switch, you probably want it on the pilot's side of the cockpit. Irrelavent in an -8, but in a -7 (for example) you need to create another bus on the pilot's side. Just a bit less convenient.

[Jamie]

Originally Posted by Yukon

Jorge,

Switch breakers are good too, and are used extensively by Van's. They are expensive, and don't offer the redundancy of a switch and a CB for turning off a circuit. The good news is, they aren't hidden out of sight like most fuse panels.

Take a look at Kahuna's post about the desirability of isolating the BMA and
GR for software re-boot. Ask the guys promoting fuses if that can be done with their system.

Of course it can, Yukon. He advocated putting *switches* on those units. Switches will work fine with breakers or fuses.

[jcoloccia]

Originally Posted by Yukon

The good news is, they aren't hidden out of sight like most fuse panels.

Since this keeps coming up with the notion of "preflighting the fuse block", I have to ask....does anyone here take apart their circuit breakers and check the contacts for corrosion or the mechanism for wear as part of their preflight? Does anyone even go around a check that every breaker is in? I sure don't. I turn the system on and perform my check...if it works, the breaker's in. Same with fuses.

What's the big deal anyhow? You ARE allowed to mount a fuse box visibly if you want but most people hide them away so it doesn't take up panel space.

Originally Posted by Yukon

Ask the guys promoting fuses if that can be done with their system.

Use a switch.

Even better, put that one device on a Klixon pullable CB. There's no law that says you can't use a combination of fuses and breakers knowing that each have advantages and disadvantages and each are appropriate (and better) in different circumstances.

[thallock]

Originally Posted by Jekyll

Tracy: Do you have a means of testing the status panel? Do you have real-time notification of a failure in your fuse status panel so you are guaranteed not to be seeing false negatives or vice-versa?

I'm being humorous here but, where does our desire for information surpass its effectiveness. Few of us have the resources to design and install BIT, be it IBIT, PBIT or CBIT (BIT=built-in-test). We rely on verifying the systems during preflight walkaround and pre/post-start proceedures (a good checklist should include verification of all systems needed for the intended flight).

Jekyll

Jekyll,

The status panel uses dual color LEDs, so voltage present indicates green, and voltage absent indicates red. Therefore, you get a positive indication of a good fuse, and you get a positive indication of a blown fuse. Very simple. Of course, there is always the question of the integrity of the wire used to connect to the fuse itself, but every self test system has limitations.

I had a lot of other ideas as to how to do this panel to make it better (blinking LEDs, enable/disable, audio, etc.), but as with any project I found the list growing out of proportion to the actual need, which was to simply show the status of all of the fuses. So, I limited the scope of the panel to my original needs, and it does what it is supposed to do.

Tracy.

[Jekyll]

Tracy:

I'm glad you recognized I was shooting for humor and not scorn. Sounds like a good system. Can you provide more detail on how you did this? Drawings, photos etc.

Jekyll