Air Conditioner inline breaker

[Let'sgoflying!]

The manufacturer says:
"We are recommending you purchase a 60 amp inline breaker or fusible link at the battery."
without any suggestion of what brand CB, or what CB might work. (won't be using a fuse)
Ideas welcome.

 

[Gary Ward]

Knowing nothing about what your asking as far as what's bests for an aircraft.
But I am curious what's wrong with using a fusible link for a AC system at the battery?

 

[Let'sgoflying!]

But I am curious what's wrong with using a fusible link for a AC system at the battery?

Hi Gary
I dont think the manufacturer is saying it’s wrong to using a fusible link, and I was saying simply that’s it’s my preference to use a CB.
Wondering if anyone can suggest one.
Thank you

 

[kontiki]

Over current protection keeps wiring from becoming a fire hazard in the event of a short. So a circuit breaker should be sized according to the wire guage being protected. It should also be placed as close to the electrical bus as possible. Refer to CH 11 of the 43-13 or better yet have someone that knows what they are doing set it up. Fuses are sacrificial. Also, kind of dated but good to know about FAA SAIB CE-13-22. Worth considering how adding this to the electrical system will affect the electrical load analysis too.

 

[Let'sgoflying!]

kontiki, good reminders on purpose, sizing & placement etc of the protection.
If anyone, anyone at all wants to try to answer my question, that would be equally (or even more so) be of value - thank you.
I promise not to assume the manufacturer has the sizing of the wire or protective device correct (as noted in the originally attached document), before proceeding.

 

[PaulMillner]

The manufacturer says:
"We are recommending you purchase a 60 amp inline breaker or fusible link at the battery."
without any suggestion of what brand CB, or what CB might work. (won't be using a fuse)
Ideas welcome.

60 Amp Circuit Breakers For Alternators | Aircraft Spruce

60 Amp Circuit Breakers For Alternators These heavy duty circuit breakers are ideal for use with aircraft alternators and other applications using high amperage. 10-32 screw terminals. 1 3/8

www.aircraftspruce.com

Or, similar from Digikey or Mouser.

I have an Arctic Air too... need to install it!

Paul

 

[Bell206]

Wondering if anyone can suggest one.

Klixon and Tyco brands are the more common choices however at a premium. Using a non-trip type CB will be more ecomonical and for this application will work. The one limiting factor though can be the physical size and configuration of the CB depending on where you want to install it.

 

[SCCutler]

I like the breaker as close to the power source (presumably, the battery or master relay) as possible. This in turn suggests a breaker designed for harsh duty environmentally.

Here is one I find now, but I did some research a while back and had identified a similar device that I liked… and I can’t find it! I’ll look again later.

https://www.amazon.com/Bussmann-CB185-60-Waterproof-Circuit-Breaker/dp/B001PYL4UA

 

[Let'sgoflying!]

I like the breaker as close to the power source (presumably, the battery or master relay) as possible. This in turn suggests a breaker designed for harsh duty environmentally.

Here is one I find now, but I did some research a while back and had identified a similar device that I liked… and I can’t find it! I’ll look again later.

https://www.amazon.com/Bussmann-CB185-60-Waterproof-Circuit-Breaker/dp/B001PYL4UA

Thanks Spike~
The battery is in the mid
-fuse, aft of the rear baggage - all interior!
I’ll have a look.

 

[kontiki]

The reason I am not recommending any particular product is because I don’t do enough in GA to know what’s acceptable with your local FSDO. I’ve been an A&P and an airline Avionics Engineer for a long time. The airline world is completely different.

I am familiar with this specific problem because I pulled a circuit like it out of an airplane I bought. The airplane I bought had two of the Tycho breakers that were identified in the SAIB. It also had a lot of other unsatisfactory breaker related problems. I haven’t got my airplane back in service yet to know what paperwork will pass muster. I’m planning on working with some AI buddies to get it going, they have local FSDO connections and can tell me what will and won’t pass muster with them.

The way I see it it’s a minor alteration provided you keep continuous electrical load below maybe 80 % of the capacity of the alternator. However, you are putting a part on the airplane that’s never been part of that airplane’s approved configuration. That’s kind of a gray area for me. AC23-27 talks about substantiation of parts used on airplanes.

An OEM can put whatever they want on an airplane provided the result is a certifiable airplane. Once the STC is issued it's part of the approved configuration. I would think the best choice is a circuit breaker that meets military or SAE specifications for aviation use. It has to be trip free, I like breakers that can be manually opened. I wouldn't load it for more than 80% of it's rated capacity. I wouldn't worry about trip time provided you don't have cascading breakers in mind.

Beech originally put a version of Tycho breaker switches identified by a Beech P/N on some models and that resulted in AD 2008-13-17. I believe they also wound up on other airplanes, approved by similarity to the Beech installations, but they were not easy to identify because the original AD points to the Beech P/N not the Tycho P/N. My guess that's why the the SAIB was issued. The last time I looked the Tycho breaker/switch did not meet any recognized aviation circuit breaker specification.

 

[Bell206]

The last time I looked the Tycho breaker/switch did not meet any recognized aviation circuit breaker specification.

FYI: aircraft circuit breakers technically fall under Standard Parts which include any parts manufactured in compliance with an established U.S. Government or industry-accepted specification. While Klixon and others are made to a Mil-Spec, most but not all Tyco CBs and other brands are mfg'rd to a UL standard which meets the requirements of a FAA standard part and one of the reasons they were used by various aircraft OEMs.

And just to add, at the Part 91 level and portions of Part 135, the local FSDO does not play an active role is determining what is acceptable during the course of regular maintenance or alteration. That falls exclusively to the mechanic or IA performing the work or installation and is covered under the applicable FAA guidance.