SV-OAT-340 wiring question

Maccool

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Dec 24, 2020
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As many others have mentioned the cable on the SV-OAT-340 sensor is 10 ft long and that's not near long enough to get from the ADAHRS in the tailcone to the 2nd or 3rd rib bay on the wing where the sensor needs to be mounted. I realize that splicing is OK, but how is it spliced? Other posts I've seen indicated that the wiring is shielded, but it doesn't look shielded to me (I'm no expert). Can I just splice that cable longer with some plain old 22ga crimped butt connectors? Or maybe some heat-shrink/low-temp solder butt connectors? Thanks for any guidance...
 

jnmeade

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Per Appendix C
FAA Advisory Circular AC 43.13-1B is an excellent resource for wire sizing requirements as well as other acceptable methods, techniques, and practices in aircraft inspection and repair.
Try Section 13, Chapter 11
 

Raymo

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Yes, you can just splice into the middle with some 22g wire. You can source the molex pins but you'll need to get the PN or order them from Dynon. No shielding required. I would solder them, if possible.
 

GalinHdz

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I would solder them, if possible.
In aviation applications, soldering wires is not recommended. Crimping is.

Soldering changes the small portion of the wire from braided to solid and makes the joint subject to breaking due to aircraft vibrations. If you must solder, then you need to have some kind of mechanical bracing before and after the "solder" joint. Proper crimping provides this mechanical bracing. If I have to solder a wire I personally use these "Solder Termination Sleeves".
11-07902a.jpg

They provide mechanical bracing in addition to the solder connection and heat shrink insulation. More expensive that just solder and heat shrink but significantly more reliable. You can get them at most electronic supply source and even at ACS. Just my 2 cents.

How to use Solder Termination Sleeves Video

:cool:
 
Last edited:

Maccool

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Dec 24, 2020
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In aviation applications, soldering wires is not recommended. Crimping is.

Soldering changes the small portion of the wire from braided to solid and makes the joint subject to breaking due to aircraft vibrations. If you must solder, then you need to have some kind of mechanical bracing before and after the "solder" joint. Proper crimping provides this mechanical bracing. If I have to solder a wire I personally use these "Solder Termination Sleeves".
11-07902a.jpg

They provide mechanical bracing in addition to the solder connection and heat shrink insulation. More expensive that just solder and heat shrink but significantly more reliable. You can get them at most electronic supply source and even at ACS. Just my 2 cents.

How to use Solder Termination Sleeves Video

:cool:
I have a bunch of those solder sleeves, but was planning on crimping with ferrules and heat-shrink. Thanks.
 

jakej

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My method - cut the wires 1 ft from the probe end. Add more wire to the pins end (excess to requirements) with staggered solder joints & then use a battery drill to twist the wires, the twist will self support the wiring however you could also use glue lined heat shrink which will also give support.
Then put the connectors (supplied fitted to the wires) into the small connector to the ADAHRS end.
now just use 2 pin M&F connector ( or standard size crimp pins/sockets, same as used on dsub connector) at the OAT end. Now you have a simple solution to extending the wire & for removal of the OAT if needed. Sometimes I fit them to an inspection panel or close to one. Simples 😉
 

Maccool

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My method - cut the wires 1 ft from the probe end. Add more wire to the pins end (excess to requirements) with staggered solder joints & then use a battery drill to twist the wires, the twist will self support the wiring however you could also use glue lined heat shrink which will also give support.
Then put the connectors (supplied fitted to the wires) into the small connector to the ADAHRS end.
now just use 2 pin M&F connector ( or standard size crimp pins/sockets, same as used on dsub connector) at the OAT end. Now you have a simple solution to extending the wire & for removal of the OAT if needed. Sometimes I fit them to an inspection panel or close to one. Simples 😉
Great overview, thanks, Quick (elementary) question...can I splice those wires in using shielded 22ga wire? It’s all I have sitting around. Some unshielded wire is in transit but won’t be here until Monday.
 

Raymo

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As stated in my previous post, yes, you can splice regular 22g wire. Nothing wrong with soldering and heat shrink, though butt splicing is much faster (assuming you have the correct crimper). I only use solder sleeves for grounding the shield on shielded wire, which is their primary purpose. Not recommended to tie to unshielded wires together. I like JakeJ's recommendation to twist the wires too.
 

Maccool

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I'm going to mount the OAT sensor on the middle inspection plate of the left wing. For ease of maintenance, can I put the sensor on a Molex connector so I can unplug it when removing the inspection panel?
 

maartenversteeg

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Should be no problem, signals on these wires are only slowly changing. Only make sure that the the Sun can't change the temperature reading (should be OK as I assume the inspection plate is on the bottom of the wing), also make sure that it is far enough out from the engine exhaust stream as that would change the temperature reading too
 

Maccool

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I appreciate the input, thanks. I realize that in the scheme of things these questions are elementary but I'm pretty new at this and I want to make sure I do this right.
 

maartenversteeg

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Building an airplane is a continuous learning process, there are so may things I don't know. Glad to be of any help, or have my answers refuted
 
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