Wing to firewall and panel wire lenght

newimaging · #1 06-23-2011, 11:46 PM

I am trying to figure out the distance from the inboard end of the wing to the firewall, and also to the panel.
I am trying to get my wires put in for heated Dynon Pitot, and autopilot servo.
Seems like the Dynon Pitot might be happy with a 16gage cable up to 9', but not sure if thats enough to make it from the.

Also, do I have to add another 1' or 2' to the lenght because of the battery to my switch run part of the cable, to get the calculation right for the amps ?

cfiidon · #2 06-24-2011, 07:03 PM

First, you must think of the entire length of the wire from the buss to the pitot heat. Methinks 14 gauge would be the better choice.

Second, for you other issue : What I decided to do was run enough wire from the wingtips/pitot/servo to extend sufficiently into the fuselage. I will place a terminal board(s) there to connect to the appropriate source. That way, everything will be wired up in the fuselage and when I take it to the airport and put the wings on, the wing wires will then be terminated.

Don

newimaging · #3 06-24-2011, 07:35 PM

Are you saying that you are adding a terminal block to the inner rib of the wing when disconnection, would that be a good idea instead of connectors.

I am interested in the distance people use from inner wing-end to the terminal block on the firewall, so I can calculate the wire size for everything I guess. Is it more then 5 feet or is that safe ?

cfiidon · #4 06-25-2011, 01:03 AM

I plan a terminal block inside the fuselage. You could use connectors, but it's not something you are going to disconnect on a routine basis. I will probably proseal the TB in place.

Five feet should be fine. It is really a function of the item you are connecting to. For instance, one manufacturer might say that 16AWG is satisfactory up to 12 feet, but recommends 14 gauge for longer runs. It's not a safety issue, simply that all wire drops voltage along the way. The longer the wire, the greater the resistance (and hence the greater voltage drop). To compensate, you use a larger wire with less resistance per foot to compensate for the longer run.

I highly recommend the Aeroelectric Connection book for your reading pleasure.

Don