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Fuse Block

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tralika

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Joined
Oct 19, 2009
Messages
96
Location
Wasilla Alaska
I've been looking for a rear terminal fuse block for quite a while. I wanted to mount a fuse block on my panel with the fuses in view but all the wiring behind the panel. Bussmann make a good quality fuse block but I had a hard time finding one for sale retail. I finally found a small company that sells the fuse blocks over the internet. I've included the link below. The owner of the company is David Swartzendruber. He stocks the fuse blocks in sizes 12 through 24 circuits. I just received mine and it looks like it's just what I was looking for. David shipped my order promptly and inexpensively by mail. I've never met him and I have no affiliation with the company. I just thought I would pass this on in case someone else is thinking of going with fuses rather than circuit breakers.

Fuseholder & Fuses
 

dcstrng

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Joined
Oct 17, 2010
Messages
913
Location
VA or NoDak
I don’t know whether this a good idea or bad, but I’m planning to do similarly with a “marine” panel (although the wiring comes to/from the front side on mine because where I plan to mount it, there is no benefit for rear – other than esthetics)
 

tralika

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Joined
Oct 19, 2009
Messages
96
Location
Wasilla Alaska
The old style glass fuses have worked for a long time. Nothing wrong with them. I prefer the newer blade type fuse. To change the glass fuse you have to remove the little cap and take out the fuse. I tend to drop things like little caps and gravity being what it is the little caps go to the lowest, darkest, hardest to find, hardest to reach place in the airplane. You may not find it until you recover the plane. The blade fuses are just simpler to use and the fuse block will make a nice clean installation.

I'm building a Just Highlander for day VFR flying. I will have a simple electrical system and fuses just make sense. Circuit Breakers are heavier, more expensive and while pretty reliable I have seen them fail in the closed position. I have never seen a fuse fail to function when overloaded. I don't think it's possible. Since I don't re-set circuit breakers in flight anymore I don't plan to change fuses in flight either.
 

TFF

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Joined
Apr 28, 2010
Messages
14,176
Location
Memphis, TN
There 's only one problem with the glass fuses, they are not the standard anymore. The price keeps going up; they use to be pennies a piece, but they can be $5 for a high amp for one. If going fuse, ATC is the best way now, unless you already have tons of them.
 

Dan Thomas

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Joined
Sep 17, 2008
Messages
5,655
The old style glass fuses have worked for a long time. Nothing wrong with them. I prefer the newer blade type fuse. To change the glass fuse you have to remove the little cap and take out the fuse. I tend to drop things like little caps and gravity being what it is the little caps go to the lowest, darkest, hardest to find, hardest to reach place in the airplane. You may not find it until you recover the plane. The blade fuses are just simpler to use and the fuse block will make a nice clean installation.

I'm building a Just Highlander for day VFR flying. I will have a simple electrical system and fuses just make sense. Circuit Breakers are heavier, more expensive and while pretty reliable I have seen them fail in the closed position. I have never seen a fuse fail to function when overloaded. I don't think it's possible. Since I don't re-set circuit breakers in flight anymore I don't plan to change fuses in flight either.
Day VFR is fine for fuses as long as the radio fuse doesn't decide to pop just when you're on downwind at a busy Mode C airport.

I used to be a flight instructor. The old Cessna 150s had fuses, and at night a blown fuse became a real hazard. Try to read the tiny, faded printing on the panel above the fuses to see which one to check. Pull it out and drop the cap on the floor, in the dark, where it rolls up under the rudder pedals somewhere. Find it, if you can, then open the glovebox and try to see if the right fuse is there. It's supposed to be. Pick it out and put it in. With luck, the dead circuit wakes up again. Without luck, the fuse either blows immediately or it doesn't fix the problem, which is sometimes oxidized contacts in the fuseholder. And oxidized contacts cause heating that can blow a fuse prematurely, too. All of this gets even more fun under an overcast on a black night when there are no ground lights and up or down gets uncertain so that you're essentially IFR. Or you might actually be in IMC. Ugh.

I prefer breakers. Never had one fuse closed, but have had old ones pop prematurely because their 30-year-old contacts have oxidized and are heating up, fooling the breaker's bimetal sensor into thinking the current load is too high. At age 60 I'm not worrying about installing new breakers that might do that. The real nice thing about breakers is that I don't need to carry spares, the cap can't fall and get lost, and all I need to do is push it back in to see if the problem was just transient. And if it's a pullable breaker I can shut down a troublesome circuit.

Trouble with breakers is cost, and a bit more weight.

Dan
 

dcstrng

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Joined
Oct 17, 2010
Messages
913
Location
VA or NoDak
I don't know that I prefer breakers/fuses... but I've newer had a fused circuit fail that I wired (I often oversize the wire to protect the machine and then under-size the fuse to protect the device... or that's my theory, but I'm no electronic-whizz, so it may be all wrong); however, I've had countless factory breaker circuits fail in various machinery... I tend to use the simplest marine-grade, cuz that's what I know and so far (at least) it seems to be a good choice...
 

Matt G.

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Joined
Nov 16, 2011
Messages
1,252
Location
Kansas, USA
[snip]I often oversize the wire to protect the machine and then under-size the fuse to protect the device... or that's my theory, but I'm no electronic-whizz, so it may be all wrong
The fuse/breaker is there to protect the wiring in the event the device fails, and the fuse/breaker should be as close to the bus as possible.
 

Lemans

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Joined
Mar 23, 2008
Messages
586
Location
Riemst Belgium
I used to build fuse-blocks for my race-cars myself. Every fuse had a LED mounted above so I could
see witch fuse was broken. Very handy during night stages.

In some cases changing the 8Amp by a 30Amp solved the problem and got me to the flying finish.
I believe I still have a print layout somewhere.
 

Pops

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Jan 1, 2013
Messages
8,800
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USA.
Day VFR is fine for fuses as long as the radio fuse doesn't decide to pop just when you're on downwind at a busy Mode C airport.

I used to be a flight instructor. The old Cessna 150s had fuses, and at night a blown fuse became a real hazard. Try to read the tiny, faded printing on the panel above the fuses to see which one to check. Pull it out and drop the cap on the floor, in the dark, where it rolls up under the rudder pedals somewhere. Find it, if you can, then open the glovebox and try to see if the right fuse is there. It's supposed to be. Pick it out and put it in. With luck, the dead circuit wakes up again. Without luck, the fuse either blows immediately or it doesn't fix the problem, which is sometimes oxidized contacts in the fuseholder. And oxidized contacts cause heating that can blow a fuse prematurely, too. All of this gets even more fun under an overcast on a black night when there are no ground lights and up or down gets uncertain so that you're essentially IFR. Or you might actually be in IMC. Ugh.

I prefer breakers. Never had one fuse closed, but have had old ones pop prematurely because their 30-year-old contacts have oxidized and are heating up, fooling the breaker's bimetal sensor into thinking the current load is too high. At age 60 I'm not worrying about installing new breakers that might do that. The real nice thing about breakers is that I don't need to carry spares, the cap can't fall and get lost, and all I need to do is push it back in to see if the problem was just transient. And if it's a pullable breaker I can shut down a troublesome circuit.

Trouble with breakers is cost, and a bit more weight.

Dan

Yes-- Things happen at the wrong time. Like the night I was on an ILS down to almost minimums in an Piper Atzec. Always said that I wouldn't fly IFR without headphones and push ot talk on the yoke. Forgot my bag with the headphones. So reporting at the OM, I dropped the mic and it rolled up and got caught around the rudder pedals. Got the flashlight out to try to get the headphones and when I turned it on the batteries fell out. I don't need anymore things to go wrong at the wrong time, I'll stick to breakers thank you. Dan
 

Dan Thomas

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Joined
Sep 17, 2008
Messages
5,655
In some cases changing the 8Amp by a 30Amp solved the problem and got me to the flying finish.
I believe I still have a print layout somewhere.
That's a recipe for a fire in an airplane. The fuse or breaker is there to protect the wiring, not the component. If the component shorts, the fuse will probably blow but the component is shot anyway. The wiring, if it gets chafed or cut by something and shorts to the airframe, will start heating instantly and can cause a fire or generate toxic smoke, so the fuse/breaker stops that.

On rare occasions control cables have chafed through battery cable insulation and either blown the cable apart or welded the control surface bearings solid. Not good. The Cessna 180/185 series had their batteries in the tailcone right next to the rudder and elevator cables, and one had to watch that someone else hadn't replaced a battery cable with a longer one that could reach the control cables. Battery cables aren't fused, and the only disconnect is the master contactor on or next to the battery box. The battery cable needs to be kept as short as practicable so it's chances of being damaged and shorted are minimized. Thousands of amps running through anything shorted to anything else is a real bad deal.

Dan
 
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