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In-Line fuses and how you handled them?

jeffsvan

Well Known Member
Members,

Just trying to get a concensus on how you handled them?

Did you use them, standardize them to one type, or remove and use a panel mounted circuit breaker?

I have mini plastic blade type on Garmin bare wire cables, standard size glass auto fuses on Electronics international gear, mini glass auto as well, and a glass aircraft fuse (thicker diameter than glass auto style) on an old digital Davtron chronograph.

How the heck can the manufacturers say this is an aviation grade component? Some of them are cheap auto knockoffs.
 
At the very least, I would out a fuse block like Stein sells that holds multiple blade fuses. I certainly prefer circuit breakers, but they cost a lot more.
 
Today's auto fuses are actually much higher quality than 'aircraft quality' fuses. Holders for glass fuses are almost always low contact pressure and corrosion-prone, leading to high resistance contacts driving heat driving thermal failure.

ATC style blocks are great, and you can get in-line singles, as well, if needed.
 
You also might look at the Blue Sea brand fuse blocks. Rather than several inline installations, I put a block FWF for the sensing wires connected directly to heavy current opportunity. Sense for volt, current, and IBSS battery charge.
 
I am a fan of the auto ATC fuses as well.
For non-critical small loads, a fuseable link can be wired in line. Fuseable links can simplify your wiring runs as they wire directly in line, are easy to fabricate, are cheap, and take no space. You can't really service them, but for things like shunts, and other sensors that are low power but need some kind of protection, they are very useful.
Just one more way to do it.
 
I hate inline fuses! Twice within the last month, I've had to troubleshoot other peoples (certified :eek:) plane and found an inline fuse to be loose.

The first one was a radio that was suddenly dead. Circuit breaker ok. But, wait; the radio isn't even wired to the circuit breaker. The breaker is a dummy and the radio is wired directly to the buss via an inline fuse that has fallen apart.

Second one: installing a new radio on a different airplane and, as I'm doing a final inspection to insure all wiring/cabling does not interfere with flight controls, low and behold, I find a floating power wire, via an improperly installed, and now disused inline fuse holder!

Use a modern fuse block, or aircraft circuit breakers and eliminate those hidden inline fuses!
 
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I've used circuit breakers for most of my protection, but for two odd, out of the way needs I have 1 amp blade fuses that I hooked up with faston connectors and heat shrink.
 
Just trying to get a consensus on how you handled them?

Fat chance of that ;)

Did you use them, standardize them to one type, or remove and use a panel mounted circuit breaker?

All kidding aside, I think you'll get general agreement on ditching tubular glass fuses.

Don't assume components sourced from the automotive world are substandard. Consumers place a very high premium on everyday reliability. Bad automotive products die a quick death in the marketplace.

Bus source (fuse block or breakers) everything you can. However, sometimes the situation requires an inline fuse. I use blade fuses for small loads. ATO/ATC blade fuses go down to 1 amp, ATM (minis) to 2 amp. Use molded holders, the kind that molds the wires into the casing, so that wire movement can't flex the terminals, and thus the fuse blades.

I also like fusible links. Personally I think a well-fabricated fusible link is extremely durable (corrosion, vibration, short current spikes, etc). Remember, blade fuses are fast-blow by design.

Circuit breakers are rarely used in line, unless it is convenient to mount them right next to the source. Remember, as a rule, any wire without circuit protection is limited to 6" or less. You can't run an unprotected wire from a voltage source to a CB mounted halfway across the panel; the entire length is a fire hazard. Nor is it a good idea to hang a CB loose in the wire, as we commonly do with a fuse holder.
 
I am a fan of the auto ATC fuses as well.
For non-critical small loads, a fuseable link can be wired in line. Fuseable links can simplify your wiring runs as they wire directly in line, are easy to fabricate, are cheap, and take no space. You can't really service them, but for things like shunts, and other sensors that are low power but need some kind of protection, they are very useful.
Just one more way to do it.

Trying to grasp the idea of making a 'fusible link'. The internet tells me that each fusible link is four wire gauge sizes smaller than the wire it is designed to protect.

I would like to set these up to work on my EIS shunt wires. My harness has 24 gauge wires, so would I just use 28 gauge wire to make these fusible links? I found some reference of a fiberglass casing to keep it from melting all over the place and starting a fire.

Any direction on how to make a well fabricated fusiable link would be appreciated! Thanks
 
Trying to grasp the idea of making a 'fusible link'. SNIP

I never use any sort of fusible link - the concept of a wire melting as a design element bothers me.

For something like a shunt connection, simple in line fuses can be soldered into the lead and then covered with heat shrink. Here is a 0.5 amp example: https://www.alliedelec.com/littelfuse-0251-500mxl/70184694/

I use these for things like power to the buzzer that sounds when the engine is not running but the ignition switch(s) is on.

Carl
 
Assuming that the ammeter will only be measuring the millivolt drop across the shunt and that no current will be flowing,
then resistors (1K ohm?) could be used instead of fuses or fusible links.
 
Thanks for the feedback, didn't realize they made little fuses I can just solder in. I might do that, or do the fusible link from B&C, not sure yet.
 
For making a link, you can use clear silicone tubing as the thermal barrier on the small gauge stuff.

On the subject of wire designed to burn, that's kinda what a fuse usually is, isn't it? If you're driving a car made in the last 5 decades, odds are very good that it has at least a few fuse links built into its wiring harness.

I do like the item Carl linked; looks like a good value for the intended use. Links tend to be very slow acting, which can be desirable or not, depending on application.

Charlie
 
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