430 W power wiring question

[Jrskygod]

I'm wiring my 430W and I'm a little confused with the power wiring for the P4002 connector. I have a 12V install and my interpretation of the diagram H-5 and related notes show 18 ga wires with oversized pins at position 11 & 12. It seems that with a maximum draw of 6.0 amps on that section of the radio (comm) that is oversized on the wires especially with the short 3 foot run I will have and the draw is somewhat intermittent. What I don't understand is with a comm load (intermittent) why I would need 18 ga. wires to each pin. As I understand it the pins themselves are only good for 5 amps each (and probably why Garmin uses two pins). Would it be prudent to run 20 ga. short pigtails from pins 11 & 12 and join them to a 18 ga. running to the 10A circuit breaker? Additionally the total max load of both the nav and comm sections together is listed as 8.5 amps. I read somewhere that the radio will not work unless both the comm and nav sections are receiving power. (I sure would like to know if that is really true.) It would seem that a 10 amp breaker could carry the load of both sections. If I increased the size of the wire from the pigtails of both the nav and comm sections from 18 ga. to 16 Ga. I could then use one circuit breaker for the entire radio which would be better in my install.

Anyway what I'm looking for here is some advice if I'm over thinking this and would end up with a problem or if this is a viable option. Of course any input as to how you did it would be helpful as well.

[SMO]

Pins 11 and 12 on connector P4002 are both power for the com side, I joined them together at the 430 and ran an 18 gauge wire with a 10 amp circuit breaker - I think this is the same as you are suggesting although I don't know what gauge I used to join them.

Pins 19 and 20 on connector P4001 are both power for the nav side, although I have them marked as "Main", so somewhere along the line I understood these to be the main power source for the box. Again I joined them at the 430 and ran a 20 gauge wire with a 5 amp circuit breaker.

[Jesse]

What Mark said is fairly standard. I understand that the com won't work if the Nav/GPS side is unpowered, but I don't think the converse is true (although not sure). If the com, for some reason, pops the breaker, it would be nice to still have the GPS. Also, if you're using a 10A breaker for both, there would be no benefit to a 16AWG wire over an 18, would there? I would recommend two circuits and two breakers, with no problem if you tie them together close to the tray and run one wire out.