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Thread: Latching power connectors? Color code?

  1. #1
    bwilson4web's Avatar
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    Latching power connectors? Color code?

    Hi,

    N19WT came with spade-style, wire connectors. In my line of work, we use polarized, latching, power connectors to prevent accidental disconnects and miss alignment. But when I checked Wicks and Spruce, I didn't find connector kits.

    I didn't find much help on the FAA web site about connector standard. However, the military has a long history of 'private proofing' connectors but they are usually heavy and expensive. I just need a better solution than spade lugs for my wing wiring.

    Right now, I'm thinking Molex, wire-to-wire, Saber connector kit. The connectors are latching, polarized and well exceed the current required. Their temperature range is -40-105 C and should be easy to anchor. But I'm new to aircraft practices.

    Is there a consensus on light aircraft, power connectors?

    Absent a credible standard, I'm going to use the following color code:
    • black - ground and current return
    • red - 12V power
    • blue - signal
    • white - legacy wire, planning to replace
    Wicks carries quality wire in these colors. In those cases where part leads or built-in conductors exist and need to be joined, I'll use color coded, heat-shrink over the joint or a colored heat-shrink band to identify the cable. As for wire joints, I'm a solder and heat-shrink fan.

    Bob Wilson

  2. #2
    FlyingRon's Avatar
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    So other than uniformly white, you're going to have uniformly blue with a few black and reds sprinkled through it?

    Except for a few appliances that only get power, there's no "proofing" that you're going to get as there's no consensus at all in the industry as to wiring harnesses.

  3. #3
    Mike Switzer's Avatar
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    This is a pet peeve of mine - almost every wire behind the panel in our 182 is white, which makes it very hard to trace wires out. In addition, they are all cut to the bare minimum length possible, which makes working on things nearly impossible. It is a 182 for crying out loud - make all the wires a couple inches longer, it will take maybe 5 lb from the useful load.

    As far as wire colors go, my MGB with electrics supplied by Lucas Prince of Darkness is easier to work on - every wire has a different color code combination. Colored & striped wire is readily available from many sources, and its use has been the standard with most of the automotive & tractor manufacturers since the 1940s, why do we still use all white wires in aircraft?

  4. #4

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    Quote Originally Posted by bwilson4web View Post
    I'm thinking Molex, wire-to-wire, Saber connector kit.

    Is there a consensus on light aircraft, power connectors?

    Absent a credible standard, ...
    opinion only - those Saber connectors look just fine.

    sources for credible standards:

    http://www.kitplanes.com/magazine/

    http://www.rst-engr.com/rst/articles/index.html

    www.rst-engr.com/rst/articles/karmic1.pdf

    www.rst-engr.com/rst/articles/karmic2.pdf

    www.rst-engr.com/rst/articles/karmic3.pdf

    www.rst-engr.com/rst/articles/karmicpinout.zip

    http://www.aeroelectric.com/articles.html

    knock yousseff out.

  5. #5

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    What you can do to be able later know what all of those identical white wire do and go to is to get a wire numbering kit and create yourself a wiring diagram as you assemble the wiring harness. That way you know that wire number 101 is avionics bus power, wire number 137 if the left position light power, etc. I did that when rebuilding an antique and I never worry about knowing what goes where.

    Airplanes typically use ring terminals for connections as they are much less likely to spontaneously disconnect than spade lug connectors. Airplanes typically, Cessna in particular, use the minimum amount of wire to A) save weight, and B) reduce cost. Every ounce counts in an airplane that has limited horsepower and every penny counts when trying to build and airplane and make a profit.

    Because airplanes are built and maintained by folks with a lot more training and certification than the typical auto assembly line worker, they have never used the keyed and color coded connectors that you see in other industries. Those connectors and color codes represent the compromise of spending a few more pennies on materials to avoid spending $$ on technician training. In aviation, the equation is reversed, which may be a problem but that is another discussion.

    So document your wiring diagram, number your wires, and don't get wrapped up wire colors or connector keys. Most A&P's won't care.

    Best of luck,

    Wes
    N78PS

  6. #6
    Not sure if we are confusing spade-style with FASTON connectors that push on to a tabbed switch or fuse block? When I think of the term 'spade', I think of a fork type connector under the head of a screw. FASTON vs Ring connectors are another story. Ring connectors are a pain to deal with under a panel when screws and lock washers are dropped on the floor. I despise the ACS mag/start switch because of this. Thankfully, the rocker or bat handle switches used today are FASTON. Cessna has used them on rocker switches for years. Only use the proper PIDG style faston. Avionics shops will only stock this style. Molex/pin connectors are also very reliable for making harness connections. These pages might be slow, but some good information here on AeroElectric Connection: http://www.aeroelectric.com/articles/faston3.pdf http://www.aeroelectric.com/articles.html

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