Hi all!
I am looking for some advice and/or best practices concerning sensor wiring splice on the firewall forward environment. Is it okay to use soldering sleeves?
Thanks
+1. Get the Omega miniature connectors. A little fiddly to get the wires under the screws IMO, but rock-solid connections and the end of crimped wires working their way loose and causing jittery displays.Here's my solution for CHT and EGT. Used Omega Connectors
Available here: https://www.mcfarlaneaviation.com/products/product/23931/
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Use the same. Added wire ferrules to prevent crushing of smaller wires, like on the pmag connections. Overkill, but I also shrink tube them. Don’t want any risk of the set screws touching other metal.https://www.aircraftspruce.com/catalog/inpages/eioverlapolc-1-10-05470.php
These work well and are small, light, inexpensive.
Do not attempt to solder TC wire.What about soldering the splice using solder sleeves? My concern is more related to the material of the joints interfering with the resistance of the thermocouple. Would that be an issue?
My 2c, this is a waste of time and not as reliable as a butt splice. Ever try taking this connection apart? Nearly impossible without damaging the wire.for low power lines, i use db-25 pins and a piece of shrink tube over them.
Soldering EGT/CHT thermocouple wires won't work. Those wires aren't copper / tin. Always some odd thing like iron and some other metal. Every try to solder to iron? Doesn't work.What about soldering the splice using solder sleeves? My concern is more related to the material of the joints interfering with the resistance of the thermocouple. Would that be an issue?
And these are exactly what failed on me enough times to throw in the towel and go with Omega connectors. And yes, I have all the correct crimp tools for all the types of connectors used on the plane, including PIDG.I am no expert but I used the connectors that came with the Dynon wiring kit. This picture was taken while doing the connection.
I also supported the connection junction between two adel clamps to keep them from getting loosen.
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Helped a friend with his funky EGT temps. It had multiple crimp splices, dissimilar wire extensions, and a toggle switch to check bank A vs. bank B. All I can say is now with proper thermocouple extension wire, elimination of the extra splices, now using above noted EI splices, elimination of the switch (went to a dual needle gauge)... his two banks read as expected. Never did in the past. What exactly the problem was, I don't know. But there was plenty of poor practice that got removed.Don’t stress about adding a dissimilar metal in a typical FWF thermocouple splice. If you add it to both leads of the TC the added voltages will cancel as long as both splices are near the same temperature.
crimp sealed butt splices for me
From Omega (all things thermocouples)The comments about not soldering thermocouples are, sadly, somewhat uninformed. Some aircraft (the HU369 jumps immediately to mind) require the EGT thermocouples to be soldered. They solder perfectly well... with silver solder. I've done tons of them. If they will stand up to life in a commercial helicopter they'll stand up to life in an RV.