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Dave S wrote:
> Ray Andraka wrote:
>
>>
>> I believe the breakers are supposed to be sized to the wire, not to
>> the radio. My transponder (was an AT150 with a trans-cal encoder, now
>> an AT165) has a 5A circuit breaker on it.
>
>
> Ray.. as many others have told me.. you are right.. you size the breaker
> to the wire.. not the device..
>
> But you also size the wire being used.. to the current carried over the
> distance carried (as the nice lil FAA book shows)...
>
> So one sizes the wires to the device,, then the breakers to the wires..
>
> In my instance it makes a difference because I've a LOT of 5 amp
> breakers. For the wire runs involved, a 1, 5 or even 10 amp breaker will
> protect my wires adequately. But I also dont want to pop a breaker in
> normal operation.. "while protecting my wiring run"
>
> By they way.. thanks for the feedback on the 5A breaker.
>
> Dave
I believe Narco has the install manual on their website.
The install manual calls for a 1.5A circuit breaker. They list the power
requirements as 1.0A receive, 1.6A transmit, 0.26A pilot lights. I can
tell you that when I bought my airplane, the fuse (changed out for
circuit breakers since then) for the transponder was marked 1.5A. That
circuit feeds just the transponder and encoder. I had constant problems
with it blowing 1.5A fuses, not always but within a couple hours. I
took it to "the Radio Shop" in Worcester MA, who was a master service
center for Narco before Narco pulled service in house. They took one
look at the install, and said the problem is the 1.5A fuse isn't
sufficient for that encoder's heater and that the 1.5A was what Narco
recommended for just the transponder. They checked the wiring to verify
no chafing and that it didn't go anywhere else, measured the current
with and without the encoder, and then remarked the fuse holder for 5A.
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Re: Sizing the CB needs... Homebuilt wiring too
