Position light breaker size

[cbnank]

Hi all,

Need help. R-7A. I have whelan strobes & position lights.

I measured from the panel bus to the end of the rudder and came up with at lest 20 foot. The standard vans electrical has a 10 amp SCB for the navigation (position) lights. If you work that out in AC43-13, I come up with a 12 gauge wire from buss to end of rudder position light.

I have several questions:

The position lights are rated at 2 amps each, times 3 (2 wing & one tail) equals 6 amps total. Whelan thought a 7 amp SCB should work. If I do that I can use a 14 gauge wire instead of 12 gauge. Also, the wire at the end of the position light is only 18 gauge wire.

The question is, can I wire a 14 gauge wire to a 18 gauge pigtail at the light end?

Also should I run 14 gauge wire to the wings or would you use the existing Vans wing wire of 18 gauge?

Thanks for your help.

[treeez]

The amp load on any one wire run is only equal to the single load of the light. Therefore, you only need to cover the 2 amp load for each individual light run. The total load only applies where all the wires come together and go to the circuit breaker so that would be the heaviest amp load section. Yes, you can wire a light wire to a heavier wire. I would use a good multi-meter to check the inline amp load for the entire system to determine what size circuit breaker to use. A friend had the recommended 7.5 amp breaker in his RV8 and it kept popping. When I checked the actual amp draw it was 8 amps so he changed to a 10 amp breaker. 18 ga wire is good for a 10 amp breaker and 14 is good for a 20 amp breaker. I would terminate all my wires at a terminal board connection, then go from there to the circuit breaker. That way you can keep everything good and tight. Hope this helps.

[GAHco]

The circuit breakers are there to protect the wiring, and of course the wire and the circuit breaker need to be rated enough to handle the expected load.

AC43-13 will give you the charts, with the wire bundled, unbundled or in conduit. In your case I believe it would be classified as unbundled or single run. Check it out.

Happy flying with your new lights.