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When to/not to use a connector?

Steve Crewdog

Steve Crewdog

Well Known Member
Patron
Wiring my aux audio systems into my GTR-200 (via an Approach Fast Stack wiring harness/hub), I could attach the incoming audio directly to the harness, but an old seadaddy taught me to always have a connector between a


In this case (if I have it right) the audio Hi/Lo comes out of the GTR harness. Lo goes to the ground, and Hi goes to the audio output (into the aux radio input). I could just run the Lo wire from the harness to the ground terminal strip, and solder the Hi wires together. But if I ever have to remove the system, I'd have to cut the Hi wire and resolder it when return it.


So it seems I should put at least a single connector in the Hi wire, or am I overthinking it?


TIA
 
depends on the accessibility to the location and expected frequency to need a connecter. i often leave extra wire and make no connection. i figure if i ever come back to that spot i will put a connecter in then. and sometimes when i do come back i will solder. i think a neat soldered joint is 100% and smaller.
 
Steve Crewdog said:
Wiring my aux audio systems into my GTR-200 (via an Approach Fast Stack wiring harness/hub), I could attach the incoming audio directly to the harness, but an old seadaddy taught me to always have a connector between a


In this case (if I have it right) the audio Hi/Lo comes out of the GTR harness. Lo goes to the ground, and Hi goes to the audio output (into the aux radio input). I could just run the Lo wire from the harness to the ground terminal strip, and solder the Hi wires together. But if I ever have to remove the system, I'd have to cut the Hi wire and resolder it when return it.


So it seems I should put at least a single connector in the Hi wire, or am I overthinking it?


TIA
Click to expand...
Don't forget to follow the Garmin installation manual guidance for audio wiring connections to the various devices in the system.

For example, when you connect the alert audio from your GDU 4XX display to the AUX1 or AUX2 audio input on your GTR 200 radio, you will be using a dedicated shielded, twisted pair with the shield connected on one end to the backshell connector on the GDU 4XX display.

GTR200AuxInAudioWiring.png

Wiring is never improved by adding any extra unnecessary connections in series between the signal source and the signal destination, so avoid any temptation to add extra connectors or wire through any junction box.

Steve
 
Molex is not the best choice for connectors

In my opinion, the Molex style connectors are not adequate for aviation use. It is better to choose the DMC series or D style (Garmin type) that have a proper crimp (and hermeticity seals in the case of DMC). I think adding additional DMC style connectors will not decrease the reliability of the circuit too much, if the added maintainability is needed.
 
Longez said:
Wiring is never improved by adding any extra unnecessary connections in series between the signal source and the signal destination, so avoid any temptation to add extra connectors or wire through any junction box.

Steve
Click to expand...

I install as few connections as possible as Steve said. Less is more better :)
 
Longez said:
Don't forget to follow the Garmin installation manual guidance for audio wiring connections to the various devices in the system.

For example, when you connect the alert audio from your GDU 4XX display to the AUX1 or AUX2 audio input on your GTR 200 radio, you will be using a dedicated shielded, twisted pair with the shield connected on one end to the backshell connector on the GDU 4XX display.

View attachment 41871

Wiring is never improved by adding any extra unnecessary connections in series between the signal source and the signal destination, so avoid any temptation to add extra connectors or wire through any junction box.

Steve
Click to expand...

Agreed, it's a balancing act of planning for repairability vs minimum interruptions in the wiring. Still thinking about it.

FWIW, I'm using an Approach Fast Stack wiring harness going out to a couple SeaRey specific items, the ACI Power Bus and ACI Gear Alert System. https://flyingsafer.com/
 
Circular (cannon) plugs

It’d be interesting to get some comments from people that’s used circular (cannon plug) style firewall pass-through connectors for all of their firewall forward wiring, including engine monitoring wiring. I understand that it’s probably better practice to have an uninterrupted wire, but for convenience purposes it’d be nice to be able to “unplug” the engine form the airframe if the engine ever needed to come out. I know the military uses plugs like this throughout their aircraft.
 
Mark33 said:
It’d be interesting to get some comments from people that’s used circular (cannon plug) style firewall pass-through connectors for all of their firewall forward wiring, including engine monitoring wiring. I understand that it’s probably better practice to have an uninterrupted wire, but for convenience purposes it’d be nice to be able to “unplug” the engine form the airframe if the engine ever needed to come out. I know the military uses plugs like this throughout their aircraft.
Click to expand...

You plan on keeping spare engines with QEC kits around? (quick engine change).
Military/airlines need to be able to do engine swaps in the field, whole different animial.
 
Walt said:
You plan on keeping spare engines with QEC kits around? (quick engine change).
Military/airlines need to be able to do engine swaps in the field, whole different animial.
Click to expand...

No, I’m not planning on a top fuel dragster style pit-stop engine change out, but you never know. LOL! I’d just like to get some “real world” feedback from people that’s maybe gone this route. It would sure make for a nice clean professional looking installation.
 
PilotjohnS said:
In my opinion, the Molex style connectors are not adequate for aviation use. It is better to choose the DMC series or D style (Garmin type) that have a proper crimp (and hermeticity seals in the case of DMC). I think adding additional DMC style connectors will not decrease the reliability of the circuit too much, if the added maintainability is needed.
Click to expand...

John, what do you base that opinion on when companies such as Dynon and Stein use them? BTW, I'm using the Molex Micro-fit system. https://www.molex.com/en-us/products/connectors/wire-to-board-connectors/micro-fit-connectors
 
Connectors

I can't stand molex connectors but they are cheap.

I MUCH prefer Deutsch connectors, and have used them for basically every connection on my -10.

They are easy to pin, more importantly, are easy to de-pin (unpin?) without ruining the connector. They have a multitude of different connector configurations, as well.

I wired everything in my workshop, terminated with Deutsch connectors. When I moved to final assembly, it was just join the connectors and done. These connectors are used on cars, motorcycles, farm equipment, etc. They are well proven in the field. I have not had any issues with them on the -10.

Highly recommended.
 
Mark33 said:
It’d be interesting to get some comments from people that’s used circular (cannon plug) style firewall pass-through connectors for all of their firewall forward wiring, including engine monitoring wiring. I understand that it’s probably better practice to have an uninterrupted wire, but for convenience purposes it’d be nice to be able to “unplug” the engine form the airframe if the engine ever needed to come out. I know the military uses plugs like this throughout their aircraft.
Click to expand...

My current airplane is wired this way, using industrial grade DSUB (not Cannon) panel mount socket in the firewall and plug for the Dynon EMS wiring. The thermocouple circuits use panel mount thermocouple sockets and plugs designed for industrial use. The power circuits for alternator and starter are normal ring fittings. It has been 100% reliable over 400+ hours and makes for a neat looking installation. I haven't needed to remove and replace the engine.
 
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Dynon EMS

Mark33 said:
It’d be interesting to get some comments from people that’s used circular (cannon plug) style firewall pass-through connectors for all of their firewall forward wiring, including engine monitoring wiring. I understand that it’s probably better practice to have an uninterrupted wire, but for convenience purposes it’d be nice to be able to “unplug” the engine form the airframe if the engine ever needed to come out. I know the military uses plugs like this throughout their aircraft.
Click to expand...

I sort of went that route.
CHT/EGT cable is terminated with Faston because the sensors were pre-terminated. However, I routed the 37-pin cable forward to a D-sub female and routed all the mating wires to a Male. It works really nice. If I want to add a sensor, just run the wire to the correct pin hole and it's good to go. Most connections are D-sub.
I do have Molex on higher power circuits. Basically lights. All are .063 six pin connectors. I've worked with them a long time. No problems.
 
PaulvS said:
My current airplane is wired this way, using industrial grade DSUB (not Cannon) panel mount socket in the firewall and plug for the Dynon EMS wiring. The thermocouple circuits use panel mount thermocouple sockets and plugs designed for industrial use. The power circuits for alternator and starter are normal ring fittings. It has been 100% reliable over 400+ hours and makes for a neat looking installation. I haven't needed to remove and replace the engine.
Click to expand...

That’s great information…thanks for the reply!
 
wirejock said:
I sort of went that route.
CHT/EGT cable is terminated with Faston because the sensors were pre-terminated. However, I routed the 37-pin cable forward to a D-sub female and routed all the mating wires to a Male. It works really nice. If I want to add a sensor, just run the wire to the correct pin hole and it's good to go. Most connections are D-sub.
I do have Molex on higher power circuits. Basically lights. All are .063 six pin connectors. I've worked with them a long time. No problems.
Click to expand...

That’s great information Paul…thanks for the reply!
 
Mark33 said:
No, I’m not planning on a top fuel dragster style pit-stop engine change out, but you never know. LOL! I’d just like to get some “real world” feedback from people that’s maybe gone this route. It would sure make for a nice clean professional looking installation.
Click to expand...

I've bought a few ex-military planes and I always end up removing those HEAVY connectors because usually they're just connecting 2 or 3 wires I'm actually using versus the 35 pins in the connector and many pounds of wire not going anywhere. It adds up in a heavy ex-military plane but much more in a light experimental home built plane.
 
Don’t see the point of the firewall connectors for our planes. Removed the engine after almost 700 hours. EGT/CHT connectors disconnect from the engines easily. Oil temp wire is a single bolt. Alternator and starter wires unbolt easily, and not appropriate for the cannon plugs anyway. Would have saved no time overall if there was a plug on the firewall since everything needs disconnected anyway. Had the engine off in a few hours, working slowly, by myself.

The cool thing about experimental is you can do whatever you want.
 
climberrn said:
The cool thing about experimental is you can do whatever you want.
Click to expand...

Some choices are made based on internet jibber jabber, may not always have a good outcome however.
Usually best to stick to the plans, KISS rules.
 
KISS principle

Steve Crewdog said:
Wiring my aux audio systems into my GTR-200 (via an Approach Fast Stack wiring harness/hub), I could attach the incoming audio directly to the harness, but an old seadaddy taught me to always have a connector between a


In this case (if I have it right) the audio Hi/Lo comes out of the GTR harness. Lo goes to the ground, and Hi goes to the audio output (into the aux radio input). I could just run the Lo wire from the harness to the ground terminal strip, and solder the Hi wires together. But if I ever have to remove the system, I'd have to cut the Hi wire and resolder it when return it.


So it seems I should put at least a single connector in the Hi wire, or am I overthinking it?
TIA
Click to expand...

The Garmin GTR-200 uses a 37 pin D-Sub Connector. No need to add connections. If radio replacement with something else is needed, you can simply "unplug" the affected pins from the D-Sub connector.

D-Sub connectors are very common in avionics. If the replacement radio also uses this style of connector, it's a simple matter to simply transfer the pins. If the replacement uses another style of connection at the rear of the radio, just cut the D-Sub pins off and install the needed pins.
 
chaskuss said:
The Garmin GTR-200 uses a 37 pin D-Sub Connector. No need to add connections. ....
Click to expand...

The SeaRey I'm building uses 2 aircraft specific systems that send audio inputs to the intercom. The ACI Power Buss sends audio when a circuit has tripped, and the ACI Gear Alert sends audio for the gear position/warning system. The Power Buss connects via a fast-on/never-off connector, but the Gear Warning system is hard wired, so I was thinking about putting a Molex connector on it, in case I ever have to remove it I won't be faced with cutting/soldering a wire in a difficult to reach location.

https://www.youtube.com/watch?v=JgOFd7bHmig&ab_channel=recreationalmobility
 
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I was a part owner of a 182 for 25 years. While we had few electrical problems (filament-style light bulbs excluded), I’d estimate that 30% of them were fixed as follows:
Find connector.
Unplug connector
Spray contact cleaner
Re-plug connector
I follow Walt’s advice, try to minimize connectors. Not for today, or tomorrow, but some day…
 
Longez said:
Don't forget to follow the Garmin installation manual guidance for audio wiring connections to the various devices in the system.

For example, when you connect the alert audio from your GDU 4XX display to the AUX1 or AUX2 audio input on your GTR 200 radio, you will be using a dedicated shielded, twisted pair with the shield connected on one end to the backshell connector on the GDU 4XX display.

View attachment 41871

Wiring is never improved by adding any extra unnecessary connections in series between the signal source and the signal destination, so avoid any temptation to add extra connectors or wire through any junction box.

Steve
Click to expand...

I'm with Steve on this. I try to keep connectors to an absolute minimum, wiring directly to components with just sufficient extra wire for access & maintenance.
 
BobTurner said:
I was a part owner of a 182 for 25 years. While we had few electrical problems (filament-style light bulbs excluded), I’d estimate that 30% of them were fixed as follows:
Find connector.
Unplug connector
Spray contact cleaner
Re-plug connector
I follow Walt’s advice, try to minimize connectors. Not for today, or tomorrow, but some day…
Click to expand...

How many connectors are on your car?
 
rocketman1988 said:
I can't stand molex connectors but they are cheap.

I MUCH prefer Deutsch connectors, and have used them for basically every connection on my -10.

They are easy to pin, more importantly, are easy to de-pin (unpin?) without ruining the connector. They have a multitude of different connector configurations, as well.

I wired everything in my workshop, terminated with Deutsch connectors. When I moved to final assembly, it was just join the connectors and done. These connectors are used on cars, motorcycles, farm equipment, etc. They are well proven in the field. I have not had any issues with them on the -10.

Highly recommended.
Click to expand...

Bob,

Regarding your choice of Using Deutsch connectors. Would you point me to the type you use and prefer?

Alan
 
Connectors

AlanL said:
Bob,

Regarding your choice of Using Deutsch connectors. Would you point me to the type you use and prefer?

Alan
Click to expand...

I have used the DTM, DT, and a couple of DTP connectors.

Most used were the DTM version which has a pin rating if 7.5 amps. The DT is good for 13 amps, while the DTP is good for 25 amps.

These connectors are pretty much dust and waterproof (see the tech specs). Moreover, the are exceptionally easy to pin AND unpin. Realize that the connector is only as good as its crimp so it’s important to use the correct tools.

These connectors are found on cars, trucks, NASCARs, boats and aircraft.

I built everything in my workshop, tested it, and stored it. When I went to the hangar for final assembly, it was a simple matter to plug the connectors into their respective mate. Everything is neat and troubleshooting, if anything goes wrong in the future, will be a breeze.

Highly recommended.
 
Wire loops

For my build, I am trying to minimize the number of connectors to reduce points of failure. As I'm wiring, I consider how I would disassemble it in the future and leave extra wire so that a connector can be cut in. This defers the installation time, weight, and cost of the connector to when it is actually needed.
 
Molex connectors

Steve Crewdog said:
John, what do you base that opinion on when companies such as Dynon and Stein use them? BTW, I'm using the Molex Micro-fit system. https://www.molex.com/en-us/products/connectors/wire-to-board-connectors/micro-fit-connectors
Click to expand...

I’ve used Molex connectors for over 20 years - never a problem, except…..

I spent over a day tracking down a pitch trim motor problem on an R-14A build. The builder followed the plans and use the Van’s wiring kit.

Ringing out the lines I finally found the problem - one of these micro connectors on the last foot or so of cable inside the elevator going to the trim motor. If memory serves there were four molex connectors in the pitch trim line between the panel and the servo, all larger pin except for the one micro before the servo.

The lesson here, more connectors does not make life easier. Just because Van’s wiring kit has them does not mean you have to use them. I also suggest never using the micro connectors.

I use 0.062” pin Molex on trim servos and LED Nav/Strobes. I use the larger 0.093” pin Molex for anything requiring more than 5 amps of power. Everything else is D connector (like autopilot servos and such).

Carl
 
Sorry

Carl Froehlich said:
I’ve used Molex connectors for over 20 years - never a problem, except…..

I spent over a day tracking down a pitch trim motor problem on an R-14A build. The builder followed the plans and use the Van’s wiring kit.

Ringing out the lines I finally found the problem - one of these micro connectors on the last foot or so of cable inside the elevator going to the trim motor. If memory serves there were four molex connectors in the pitch trim line between the panel and the servo, all larger pin except for the one micro before the servo.

The lesson here, more connectors does not make life easier. Just because Van’s wiring kit has them does not mean you have to use them. I also suggest never using the micro connectors.

I use 0.062” pin Molex on trim servos and LED Nav/Strobes. I use the larger 0.093” pin Molex for anything requiring more than 5 amps of power. Everything else is D connector (like autopilot servos and such).

Carl
Click to expand...

Sorry but I have to disagree on molex connectors; they are not even in the same league as Deutsch connectors…
 
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