garmin gap 26 pitot (heated and regulated)

[SeanM]

I'm installing the garmin gap 26 pitot (heated and regulated) and going off the G3X touch install manual. I'm just wiring to the wing roots at this point.

It looks like I'll need to go with unshielded 12 gauge for the main power.

I'm not sure what gauge I'll need for the regulator discrete output (blue wire). Coming out of the regulator it's 22 gauge. I'm not seeing in the manual anything about draw on the blue wire. Am I safe to assume I can use 22 gauge?

[BrianDC]

I pulled a 22 wire and just about at the same spot in my build. If you read in the g3x manual it just shorts to ground as a signal wire so no need for anything thicker.

Working on figuring out the other wires for servo currently. How many and what size. I swear I have to think 20 steps ahead sometimes!

[Raiz]

Sean, it will draw milliamps, so 22 gauge will be absolutely fine. The clue is in the name "discrete output", details of which are in section 26.5.9 of the G3X touch manual.

When the probe is on and hot, this wire is connected to ground (0 volts) by the GAP26 controller. The GEA24 or GAD27 (whichever one you connect the blue wire to) can sense when that wire is at (or close to) 0 volts and it uses that to detect whether the probe is hot or not.

[rocketman1988]

I have been talking to the avionics shop and they recommended 14 AWG wire for the pitot. If you are using a VPX, I do not believe the 12 AWG wire will fit the connector...

Here are the expected current requirements:

Probe Temperature/Amps
-40?C (-40?F)/ 12 Amps
0?C (32?F)/ 9.25 Amps
50?C (122?F)/ 7.3 Amps
100?C (212?F)/ 5.85 Amps
175?C (347?F)/ 4.36 Amps

[AviatorJ]

I used 14 gauge on my install.

[BillL]

Originally Posted by rocketman1988

I have been talking to the avionics shop and they recommended 14 AWG wire for the pitot. If you are using a VPX, I do not believe the 12 AWG wire will fit the connector...

Here are the expected current requirements:

Probe Temperature/Amps
-40?C (-40?F)/ 12 Amps
0?C (32?F)/ 9.25 Amps
50?C (122?F)/ 7.3 Amps
100?C (212?F)/ 5.85 Amps
175?C (347?F)/ 4.36 Amps

I used a AWG 14 and 15A breaker. That -40F/C is the start up amperage, not the steady state.

[SeanM]

Ok thank you everyone for setting me set straight. Will go with 14awg for the pitot (I am planning on vertical power). I will also continue the discrete line with 22awg.


I was able to get the left landing light wired, pics here: https://imgur.com/a/Uo8v51w

[rdamazio]

I guess I was the most conservative here, and went with 12ga shielded (M27500-12TG2T14) for this - for the total distance, since I'm not grounding locally, Vans actually recommends 10ga. I got shielded mostly thinking that I didn't want it to interfere with my wingtip NAV antenna (if I'm at a very low temp needing pitot heat, there's a good chance I'm in the soup or about to be).

[g3xpert]

The G3X Installation manual has the following note in section 5.5.2:

Notes for 14V Installation: Aircraft power wiring to probe should be minimum 14 AWG up to 12 FT, 12 AWG from 13 to 20 FT, and 10 AWG from 21 to 30 FT.

Depending on your wiring, many RVs will fall right around the 12 FT length. Remember, a fuse or circuit breaker is there to protect the wiring, not the unit. Even though the normal draw of the GAP 26 is quite a bit lower than 15 amps, you need the wiring size to be sufficient to pop the circuit breaker before melting anything.

Thanks,
Levi Self

[RandyAB]

I used a 12 AWG twisted pair with Deutsch connectors at the regulator and at the wing root. I did that because of the run length which is greater than 12 ft as Levi says.