Alternator Wire Size

Does any one know the correct size of the wire that runs from the terminal on the back of the alternator to the ammeter on a '63 Cherokee 180?


  • If your alternator is under 55 amps, #6 wire is OK. If you have up to 70 amps, #4 is OK. This is if you use copper. You will need 96 inches of it.
  • edited January 4

    This is an old thread but... On a PA-28-181, I need to have the wire from the alternator to the ammeter replaced. I'd like to buy it and have it on hand for the A&P on the next maintenance . I'm having trouble finding sources for the #6 wire that meets the mil spec. Any tips/recommendations for sourcing this wire? Thanks...

  • Is M22759/16-6-9 the correct code for your application?

  • It's hard to tell. I'm trying to figure that out... the part number for the wire is 87373-06 according to the Archer parts catalog, but none of the suppliers refer to it that way. I don't see any references to Mil Spec in the Archer manuals.

  • Piper 87373-06 isn't a wire, it's a "cable assembly," consisting of 19' of M22759/16-6-9 with ring terminals bonded to each end using a mil-spec crimper. The rubber boots that go over the ends are sold separately. If your existing boots are in good shape, and your A&P is comfortable making a cable assembly, you can just buy the raw wire and terminals and let him put it together. If not, you can probably buy the complete assembly from some place like Aero-Electric.

  • Super! thanks for that answer Seneca... I think the rubber boots are good and I'll double check. I see suppliers with M22759 and the terminals so that'll be my route. Appreciate it...

  • Great, let us know how you make out. I'm glad you're replacing the entire length. I saw one of these recently where some mid-cable damage was repaired with a threaded copper splice. Problem was the splice had corroded, and when all the lights were activated and the system pulled maximum current, the bus dropped out of regulation and all the avionics shut down. With a clean new cable you'll never have this problem.

    BTW, is your Archer older than an '83? And if it is, does it have the new style current meter with the external shunt?

  • Yeah, the wire has thin insulation and damage (can see the conductor) near the alternator terminal and may have other issues along it's length so we'll replace the whole thing. It's a '79 Archer. It has the original ammeter.

  • You might check to make sure AD 86-17-01 was complied at some point. It replaces the original ammeter with one having an external shunt, and eliminates a potential fire hazard.

  • edited January 4

    Thanks, I just bought the plane 2 weeks ago so I'm still feeling my way around it. I have the logbook archives in front of me and there's an entry for that AD 86-17-01 "P/C/W & Terminated 3/26/87." So it looks like it was replaced... That doesn't change the wiring replacement approach correct? ...anyway that's for the A&P. I'll point that AD out if it's not on his mind.

  • the studs on both current meters are the same diameter, so you should be good.

    welcome to the owner society, and your new plane.

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