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Insulation displacement connectors????

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ceengland7(at)gmail.com
Guest

Posted: Wed Jul 15, 2015 2:15 pm Post subject: Insulation displacement connectors????

Anyone know if any type of insulation displacement crimp connectors have ever been used in aircraft applications? I used hundreds (thousands?) of EA-7759 Plain B Wire Connectors, similar toÂ http://www.ebay.com/itm/371364009928?rmvSB=true



in burglar alarm & other data cable installations, & never have had a failed connection in 3 decades (though admittedly, I was stripping & twisting the wires prior to crimping). For those who haven't seen these, they have 'teeth' inside that pierce the insulation when crimped.

I'm looking at the need to 'daisy chain' several signal grounds from a single dSub pin (in this case, an intercom), and these tiny connectors really look attractive to stagger the joints over several inches of wire near the pin. I tested one by opening the closed end with a pair of pliers, running the 'trunk' wire through the connector, inserting the 'branch' wire, and crimping (no wire stripping involved). Seems to work fine in penetrating the tefzel insulation, and I can't budge the wires with a manual tug test.Â 

I have no desire to do this for high current applications, but for signal wires, it sure makes an attractive package due to it's small size. Not sure about the type of insulation, but I'm pretty sure it won't spontaneously combust & drag the plane out of the sky.

Thoughts?

Charlie



  [quote][b]

billp(at)wwpc.com
Guest

Posted: Wed Jul 15, 2015 2:58 pm Post subject: Insulation displacement connectors????

Charlie,

       

       I know splicers use to love these things but even the telco's       outlawed these in the 70's (i think). I'm surprised you can even       find them on eBay.

       

       I guess you can use whatever you want to bet your life on in       experimental but I'd stick with what's in common aeronautical use.

       

       Bill

       

       On 7/15/15 3:12 PM, Charlie England wrote:

     

     [quote]       Anyone know if any type of insulation displacement         crimp connectors have ever been used in aircraft applications? I         used hundreds (thousands?) of EA-7759 Plain B Wire Connectors,         similar toÂ          http://www.ebay.com/itm/371364009928?rmvSB=true

         

         

         

         in burglar alarm & other data cable installations,           & never have had a failed connection in 3 decades (though           admittedly, I was stripping & twisting the wires prior to           crimping). For those who haven't seen these, they have 'teeth'           inside that pierce the insulation when crimped.

         

         

         I'm looking at the need to 'daisy chain' several signal           grounds from a single dSub pin (in this case, an intercom),           and these tiny connectors really look attractive to stagger           the joints over several inches of wire near the pin. I tested           one by opening the closed end with a pair of pliers, running           the 'trunk' wire through the connector, inserting the 'branch'           wire, and crimping (no wire stripping involved). Seems to work           fine in penetrating the tefzel insulation, and I can't budge           the wires with a manual tug test.Â 

         

         

         I have no desire to do this for high current applications,           but for signal wires, it sure makes an attractive package due           to it's small size. Not sure about the type of insulation, but           I'm pretty sure it won't spontaneously combust & drag the           plane out of the sky.

         

         

         Thoughts?

         

         

         Charlie

       

        	  Quote: 	
		  

	
     [b]

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Jul 15, 2015 5:27 pm Post subject: Insulation displacement connectors????

At 05:12 PM 7/15/2015, you wrote:

  	  Quote: 	
		  Anyone know if any type of insulation displacement crimp connectors have ever been used in aircraft applications? I used hundreds (thousands?) of EA-7759 Plain B Wire Connectors, similar toÂ 

  http://www.ebay.com/itm/371364009928?rmvSB=true



 in burglar alarm & other data cable installations, & never have had a failed connection in 3 decades (though admittedly, I was stripping & twisting the wires prior to crimping). For those who haven't seen these, they have 'teeth' inside that pierce the insulation when crimped 	


   Suggest you use bussed d-sub connectors



  http://tinyurl.com/nzm3e2f



   I've got some bussing boards available if

   you want them.



 



 

 

   Bob . . .    [quote][b]

ceengland7(at)gmail.com
Guest

Posted: Thu Jul 16, 2015 4:54 am Post subject: Insulation displacement connectors????

Outlawed in the '70s? Maybe so on that particular connector, but I've watched AT&T techs useÂ http://www.specialized.net/Specialized/3M-Scotchlok-IDC-UR2-Connectors-1926-AWG-100Pk-4051.aspx



as recently as a few weeks ago.Â 

I appreciate the 'be safe' sentiment, but 'bet your life' on the signal wires in an intercom? Isn't that a bit of a knee-jerk reaction to anything unfamiliar? If I'm not mistaken, this list came out of the desire to find products and techniques that are *not* 'in common aeronautical use', so we can improve on the products and/or techniques. We wouldn't have composite airframes (or even aluminum ones) if someone hadn't been the 1st to use something that was not 'in common aeronautical use'.

It would be more helpful to me if you could say something at least marginally quantified, like, 'That terminal fails in 0.05% of connections, vs a 0.00004% failure rate for PIDG terminals'.

Thanks,

Charlie

On Wed, Jul 15, 2015 at 5:57 PM, Bill Putney <billp(at)wwpc.com (billp(at)wwpc.com)> wrote:

[quote]                   Charlie,

       

       I know splicers use to love these things but even the telco's       outlawed these in the 70's (i think). I'm surprised you can even       find them on eBay.

       

       I guess you can use whatever you want to bet your life on in       experimental but I'd stick with what's in common aeronautical use.

       

       Bill

       

       On 7/15/15 3:12 PM, Charlie England wrote:

     

      	  Quote: 	
		         Anyone know if any type of insulation displacement         crimp connectors have ever been used in aircraft applications? I         used hundreds (thousands?) of EA-7759 Plain B Wire Connectors,         similar toÂ          http://www.ebay.com/itm/371364009928?rmvSB=true

         

         

         

         in burglar alarm & other data cable installations,           & never have had a failed connection in 3 decades (though           admittedly, I was stripping & twisting the wires prior to           crimping). For those who haven't seen these, they have 'teeth'           inside that pierce the insulation when crimped.

         

         

         I'm looking at the need to 'daisy chain' several signal           grounds from a single dSub pin (in this case, an intercom),           and these tiny connectors really look attractive to stagger           the joints over several inches of wire near the pin. I tested           one by opening the closed end with a pair of pliers, running           the 'trunk' wire through the connector, inserting the 'branch'           wire, and crimping (no wire stripping involved). Seems to work           fine in penetrating the tefzel insulation, and I can't budge           the wires with a manual tug test.Â 

         

         

         I have no desire to do this for high current applications,           but for signal wires, it sure makes an attractive package due           to it's small size. Not sure about the type of insulation, but           I'm pretty sure it won't spontaneously combust & drag the           plane out of the sky.

         

         

         Thoughts?

         

         

         Charlie

       

        	  Quote: 	
		  

	
     



ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List

tp://forums.matronics.com

_blank">http://www.matronics.com/contribution



	


[b]

ceengland7(at)gmail.com
Guest

Posted: Thu Jul 16, 2015 5:10 am Post subject: Insulation displacement connectors????

On Wed, Jul 15, 2015 at 8:25 PM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:

 	  Quote: 	
		    At 05:12 PM 7/15/2015, you wrote:

  	  Quote: 	
		  Anyone know if any type of insulation displacement crimp connectors have ever been used in aircraft applications? I used hundreds (thousands?) of EA-7759 Plain B Wire Connectors, similar toÃ‚ 

  http://www.ebay.com/itm/371364009928?rmvSB=true



 in burglar alarm & other data cable installations, & never have had a failed connection in 3 decades (though admittedly, I was stripping & twisting the wires prior to crimping). For those who haven't seen these, they have 'teeth' inside that pierce the insulation when crimped 	


 Â  Suggest you use bussed d-sub connectors



  http://tinyurl.com/nzm3e2f



 Â  I've got some bussing boards available if

 Â  you want them.



 



 

 

 Â  Bob . . .     	  Quote: 	
		  	


	


Thanks, Bob; I've already got one of those dSub avionics GND busses mounted in the plane. My specific application for those crimps is the signal ground terminal in a DRE intercom (it has two ground pins in the 25pin dSub which are electrically common internally). My intent was to run one of the gnd pins to the avionics GND bus and the other to the gnd terminals of the various inputs/outputs (mic, headset, music, etc) to the intercom. The crimps would have been used to bring the various signal ground wires to within the 1st few inches of dSub connector on the DRE.

Would it work as well to just take all those signal grounds to the avionics dSub ground bus? I was trying to take the signal grounds directly to the intercom to keep ground loop possibilities to an absolute minimum, and an additional dSub bus for just 3 or 4 wires seems to be overkill (and bulky).

Thanks,

Charlie



  [quote][b]

billp(at)wwpc.com
Guest

Posted: Thu Jul 16, 2015 6:48 am Post subject: Insulation displacement connectors????

I know a lot of guys have the old beans       squirreled away but they tend to make noisy connections and are       corrosion prone. The Scotchloks are what the telco's moved to       after they outlawed the beans. 

       

       I take things about my airplane very seriously. If nothing else I       use the "How stupid would I feel" rule. Like how stupid would I       feel if my intercom quit on short final to a busy towered airport       in marginal weather because I didn't take the time to strip the       wires and use the right connectors?

       

       It's a human factors thing. People can handle about 3 things going       wrong before they completely unravel. If the weather suddenly gets       bad you can turn around and go the other way, add strong winds in       that reverse direction now depleting your fuel faster than you       planned. If the intercom goes out and you can't contact       Flightwatch or ATC to find out where the closest open airport is       and you've got a real problem It wouldn't have been a big problem       in CAVU but this day it's the third thing. I don't mean to say       that every shortcut you take is going to kill you but you never       know what the third thing is going to be.

       

       There are old pilots and there are bold pilots but there are very       few old bold pilots.

       

       Bill

       

       Â On 7/16/15 05:52, Charlie England wrote:

     

     [quote]       Outlawed in the '70s? Maybe so on that particular         connector, but I've watched AT&T techs useÂ          http://www.specialized.net/Specialized/3M-Scotchlok-IDC-UR2-Connectors-1926-AWG-100Pk-4051.aspx

         

         as recently as a few weeks ago.Â 

         

         

         I appreciate the 'be safe' sentiment, but 'bet your life'           on the signal wires in an intercom? Isn't that a bit of a           knee-jerk reaction to anything unfamiliar? If I'm not           mistaken, this list came out of the desire to find products           and techniques that are *not* 'in common aeronautical use', so           we can improve on the products and/or techniques. We wouldn't           have composite airframes (or even aluminum ones) if someone           hadn't been the 1st to use something that was not 'in common           aeronautical use'.

         

         

         It would be more helpful to me if you could say something           at least marginally quantified, like, 'That terminal fails in           0.05% of connections, vs a 0.00004% failure rate for PIDG           terminals'.

         

         

         Thanks,

         

         

         Charlie

       

       

         On Wed, Jul 15, 2015 at 5:57 PM, Bill           Putney <billp(at)wwpc.com (billp(at)wwpc.com)>           wrote:

            	  Quote: 	
		                              Charlie,

                 

                 I know splicers use to love these things but even the                 telco's outlawed these in the 70's (i think). I'm                 surprised you can even find them on eBay.

                 

                 I guess you can use whatever you want to bet your life                 on in experimental but I'd stick with what's in common                 aeronautical use.

                 

                 Bill

                 

                 On 7/15/15 3:12 PM, Charlie England wrote:

               

                	  Quote: 	
		                   Anyone know if any type of insulation                   displacement crimp connectors have ever been used in                   aircraft applications? I used hundreds (thousands?) of                   EA-7759 Plain B Wire Connectors, similar toÂ                    http://www.ebay.com/itm/371364009928?rmvSB=true

                   

                   

                   

                   in burglar alarm & other data cable                     installations, & never have had a failed                     connection in 3 decades (though admittedly, I was                     stripping & twisting the wires prior to                     crimping). For those who haven't seen these, they                     have 'teeth' inside that pierce the insulation when                     crimped.

                   

                   

                   I'm looking at the need to 'daisy chain' several                     signal grounds from a single dSub pin (in this case,                     an intercom), and these tiny connectors really look                     attractive to stagger the joints over several inches                     of wire near the pin. I tested one by opening the                     closed end with a pair of pliers, running the                     'trunk' wire through the connector, inserting the                     'branch' wire, and crimping (no wire stripping                     involved). Seems to work fine in penetrating the                     tefzel insulation, and I can't budge the wires with                     a manual tug test.Â 

                   

                   

                   I have no desire to do this for high current                     applications, but for signal wires, it sure makes an                     attractive package due to it's small size. Not sure                     about the type of insulation, but I'm pretty sure it                     won't spontaneously combust & drag the plane out                     of the sky.

                   

                   

                   Thoughts?

                   

                   

                   Charlie

                 

                  	  Quote: 	
		  

	
               



ist" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List

tp://forums.matronics.com

_blank">http://www.matronics.com/contribution



	
             

           

	
     [b]

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Jul 16, 2015 7:00 am Post subject: Insulation displacement connectors????

 	  Quote: 	
		  

 It would be more helpful to me if you could say something at least marginally quantified, like, 'That terminal fails in 0.05% of connections, vs a 0.00004% failure rate for PIDG terminals'. 	


    How about, "I used ID connectors and ribbon cable

    in a pitch trim project on a Lear waaayyy back when.

    At about the 15-year mark, I inquired of the field

    service guys who were supporting that product. Failure

    rates were pleasingly low; that product was

    a fleet retrofit of about 500+ airplanes and the

    pitch trim controllers came in for attention about

    5x a year . . . so about 1%/year for the design.

    The ID connection devices accounted for about 50% of the

    service issues.



    Further, that box was located in the vertical fin,

    just under the leading edge of the stabilizer . . .

    hence, subject to about the worst of the sheltered

    environs on the aircraft.



    From that experience I would deduce that while

    the failure rates for ID connections were low,

    they still accounted for the majority of field

    failures in the design.



    Keep in mind also that the teleco's and network

    communities have been using ID connections for

    decades . . . of course the environments are not nearly

    as severe as the interior of a biz-jet's vertical fin . . .

    but still subject to humidity, temperature cycles and

    exposure to noxious atmosphere. It would seem that

    an ID connector used with wires in the connector's

    design window is a low risk venture.



 

   Bob . . .    [quote][b]

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Jul 16, 2015 7:08 am Post subject: Insulation displacement connectors????

 	  Quote: 	
		  

 Thanks, Bob; I've already got one of those dSub avionics GND busses mounted in the plane. My specific application for those crimps is the signal ground terminal in a DRE intercom (it has two ground pins in the 25pin dSub which are electrically common internally). My intent was to run one of the gnd pins to the avionics GND bus and the other to the gnd terminals of the various inputs/outputs (mic, headset, music, etc) to the intercom. The crimps would have been used to bring the various signal ground wires to within the 1st few inches of dSub connector on the DRE.



 Would it work as well to just take all those signal grounds to the avionics dSub ground bus? I was trying to take the signal grounds directly to the intercom to keep ground loop possibilities to an absolute minimum, and an additional dSub bus for just 3 or 4 wires seems to be overkill (and bulky). 	


    The core idea for the AGB was to craft a single

    point ground for all signals, power and shields.

    If it's just 3-4 wires and just shields, why

    not solder and heat-shrink?



    In reliability studies, a connector drives up

    parts count . . . a soldered joint is calculated

    as the joining of several parts into one part

    such that there is better than 10 to the minus

    bazillion reliability. Solder and shrink is almost

    never a bad idea. Is is frowned upon in the factories

    because solder is a skill-driven process with tools

    that burn fingers, upholstery, carpets, etc. But

    for the OBAM aircraft crowd, solder should represent

    no unsurmountable hazard.



 

   Bob . . .    [quote][b]

edpav8r(at)yahoo.com
Guest

Posted: Thu Jul 16, 2015 7:48 am Post subject: Insulation displacement connectors????

One additional data point.  I used IDCs very similar to those in the OP's question (mine were blue and slightly smaller) to wire an alarm system in my last home in 2004.  Those connections were in an attic in Phoenix, where under-roof temperatures were regularly above 120 deg F (no mechanical stress or vibration, and very low humidity).  The alarm system was functioning perfectly when I sold the house in March, almost eleven years after installation.



Eric



On Jul 16, 2015, at 7:59 AM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:

[quote]   	  Quote: 	
		  

 It would be more helpful to me if you could say something at least marginally quantified, like, 'That terminal fails in 0.05% of connections, vs a 0.00004% failure rate for PIDG terminals'. 	


    How about, "I used ID connectors and ribbon cable

    in a pitch trim project on a Lear waaayyy back when.

    At about the 15-year mark, I inquired of the field

    service guys who were supporting that product. Failure

    rates were pleasingly low; that product was

    a fleet retrofit of about 500+ airplanes and the

    pitch trim controllers came in for attention about

    5x a year . . . so about 1%/year for the design.

    The ID connection devices accounted for about 50% of the

    service issues.



    Further, that box was located in the vertical fin,

    just under the leading edge of the stabilizer . . .

    hence, subject to about the worst of the sheltered

    environs on the aircraft.



    From that experience I would deduce that while

    the failure rates for ID connections were low,

    they still accounted for the majority of field

    failures in the design.



    Keep in mind also that the teleco's and network

    communities have been using ID connections for

    decades . . . of course the environments are not nearly

    as severe as the interior of a biz-jet's vertical fin . . .

    but still subject to humidity, temperature cycles and

    exposure to noxious atmosphere. It would seem that

    an ID connector used with wires in the connector's

    design window is a low risk venture.



 

   Bob . . .

[b]

ceengland7(at)gmail.com
Guest

Posted: Thu Jul 16, 2015 9:58 am Post subject: Insulation displacement connectors????

On July 16, 2015 10:05:36 AM CDT, "Robert L. Nuckolls, III" <nuckolls.bob(at)aeroelectric.com> wrote:

 	  Quote: 	
		  

>

>Thanks, Bob; I've already got one of those dSub avionics GND busses 

>mounted in the plane. My specific application for those crimps is 

>the signal ground terminal in a DRE intercom (it has two ground pins 

>in the 25pin dSub which are electrically common internally). My 

>intent was to run one of the gnd pins to the avionics GND bus and 

>the other to the gnd terminals of the various inputs/outputs (mic, 

>headset, music, etc) to the intercom. The crimps would have been 

>used to bring the various signal ground wires to within the 1st few 

>inches of dSub connector on the DRE.

>

>Would it work as well to just take all those signal grounds to the 

>avionics dSub ground bus? I was trying to take the signal grounds 

>directly to the intercom to keep ground loop possibilities to an 

>absolute minimum, and an additional dSub bus for just 3 or 4 wires 

>seems to be overkill (and bulky).



    The core idea for the AGB was to craft a single

    point ground for all signals, power and shields.

    If it's just 3-4 wires and just shields, why

    not solder and heat-shrink?



    In reliability studies, a connector drives up

    parts count . . . a soldered joint is calculated

    as the joining of several parts into one part

    such that there is better than 10 to the minus

    bazillion reliability. Solder and shrink is almost

    never a bad idea. Is is frowned upon in the factories

    because solder is a skill-driven process with tools

    that burn fingers, upholstery, carpets, etc. But

    for the OBAM aircraft crowd, solder should represent

    no unsurmountable hazard.

   Bob . . . 

Solder/shrink is what I've done in other places, so that's no problem. But a 10 second operation vs a 10 minute one surely is tempting.

dlj04(at)josephson.com
Guest

Posted: Thu Jul 16, 2015 11:01 am Post subject: Insulation displacement connectors????

In a word, no. B connectors are ugly, but work well given two 

conditions: (a) DC sealing current to re-establish connection when 

compromised by oxidation, and (b) no vibration. The later jelly-B 

connectors try to solve the oxidation problem by immersing the pierces 

wire in vaseline to keep air out. Not in my airplane.

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