Circuit Breaker Size Question

[N208ET]

What would be the typical amp rated breakers used for a A210 and KT76A. I used a 10 amp for the A210 my first time around and it seemed pretty big for the job but I must of gotten that information from somewhere. I have a 5 amp breaker for the King.

Second question, I robbed ships power for my 796 from the radio, I've been flying with it for a while (BTW amazing piece of hardware). What is the general opinion, ok or tabo. Should I have the 796 on its own breaker. I am in the middle of a panel upgrade. Just for info, my mission is day night VFR, going from all steam to a Dynon D180, Garmin 796, Ipad Mini, Backup 2 1/4 airspeed. I will post a pic in the panel section when it looks half way decent. My instrument panel has been livin in the getto for much too long
:-)

Randy
8A

[cfiidon]

I looked up specs for the A210 and saw that it will draw 5Amps max, and the KT76 was 1.8 amps.

If I were designing for power for these components I would would use a 7A minimum for the A210 with the appropriate wire size. A 2A would probably suffice for the KT76A with a dedicated breaker, but if I thought I might tap into that breaker for something else I would go with a 5A. Breakers/fuses are matched to the wire size.

The way I design for power is to determine the maximum current draw of the component, determine the required wire size based on current draw and length of the wire run, then choose the appropriate circuit breaker based on the wire size.

Of course there is nothing wrong with using too large a wire and breaker other than weight.

Don

[Walt]

The A210 calls for a 10 amp breaker and the KT 76A specs a 3 amp breaker. Typical current draws for these units is about half the spec'd breaker value, but don't forget, the breaker is really there to protect the wiring, not the unit itself. Both units are internally fused to protect them.

If you tap off a breaker for another device you still must use the appropriate size wire. So, if you tap off the A210 breaker with a 24 ga wire for the 796 the 24ga wire is unprotected and will melt before the breaker trips.

[N208ET]

What do you think about having a dedicated breaker for the Garmin 796, or just keep stealing power from my radio for it.


Randy
8A

[humptybump]

I chose a breaker for the 796/795 GPS and a separate one for the GLD 39. PArt of my reasoning was that if I needed to conserve power (such as alternator failure) I wanted some options for reducing items as needed.

Example - the GDL39 would be an early candidate to go offline before the GPS or radio. The radio would be last of those three. If you have access to their switches, then you have that option to get the same result. (my GDL 39 is remote).

[Walt]

Originally Posted by N208ET

What do you think about having a dedicated breaker for the Garmin 796, or just keep stealing power from my radio for it.
Randy
8A

I think you should have a dedicated low amperage breaker for these items as they all use very small 22 or 24 gage wire in the harnesses. A 1 or 2 amp breaker could easily run the 796 and a GDL39 and would be better than tapping off the 10a radio breaker.

[humptybump]

Originally Posted by Walt

A 1 or 2 amp breaker could easily run the 796 and a GDL39 and would be better than tapping off the 10a radio breaker.

Just an FYI - a 1A breaker will run the GDL39 but it will not run the 796. (yes, I found out the QA way ...I have a 1A and a 3A for the two pieces of equipment and unintentionally sourced each to the other's CB.

[N208ET]

I have just the spot for those breakers and I will put them in for both my 796 and gdl 39.

Randy
8A

[N208ET]

This is the way its shaping up. I am running one breaker for both the GDL 39 and the 796. I was going to run one for each to be able to pull the breaker to conserve power, but my friend pointed out that I could just turn off power to the GDL 39 and GPS directly, they are both in reach. Sometimes its the simplest solutions that make me smack myself on the forehead!


Randy
8A