How Many Circuit Breakers To Power Skyview

[Dynon101]

Page 4-9
Power Input
SkyView displays have a primary power input that is compatible with 12 volt
and 24 volt systems (10 to 30 volts DC). There are two unterminated solid red primary
power input wires (to reduce current loading in each wire-these are not for redundancy and
both must be connected to the same power source) and two unterminated solid black primary
ground wires.

Does this imply that the system needs two Circuit Breakers?

I read that mean two separate circuit breakers powered from the same electrical bus and each powering one of the two red wires. Each of my circuit breakers are 5 amps. Is this going to prevent a problem?

 

[jakej]

From Rev Z page 4-17 (should always read the latest version) -- Power Input
"There are two unterminated solid red primary
power input wires (to reduce current loading in each wire-these are not for redundancy and
both must be connected to the same power source" in other words both wires go to the 1 x power source ie 1 x circuit (breaker). Why ? because the electrical load on one pin is right at it's limit & Dynon has probably (wisely) decided to spead that load between 2 pins. FYI - many other avionics manufacturers use the same approach with their boxes

 

[dynonsupport]

Right after that:

"Ensure that there is an appropriately rated circuit breaker or replaceable fuse on the primary power input. Reference the Power Section of the System Planning Section for more information."

In the System Planning page is the attached image.

So no, you don't need two breakers. Breakers are to protect wires. All wires are 22 AWG, which is rated for 5A. So a single 5A breaker protecting two wires is completely fine, and is what we expect to be implemented. As Jake says, we split across two wires because the rating for a D-SUB pin is 5A, and we're being conservative in splitting that power across two pins.

 

[krw5927]

Wouldn't 2 breakers actually be a bad thing here?  Consider that one breaker may fail, while the other does not.  If this happens, all Skyview power will be received through one wire (ok) into one dsub pin (not ok).

 

[dynonsupport]

The wire and connectors are rated at 5A. As long as you don't have more than a 5A breaker on a given wire, I don't really see how you can put more than 5A through a section of wire or a connector. The D-SUB is rated at 5A, the use of two is just conservative. But it isn't buying you anything either.