Hello community,
I want to use shielded cables for driving the stepper motors but think about putting plugs inbetween right after the motors. That way I can easily disconnect everything or adapt cables lengths if needed.
Are there any recommendations from community side?
I thought about using 5 pin AMP Superseal plugs/connectors but is that working with shielded cables?
The 5. pin would be for the shielding I want to connect to the motor chassis itself.
Thanks in advance! 
There’s lots of folks that use CAT-5… That’s for the cabling, if you can’t find shielded 4/22 (I see it a lot as “alarm cable” for home security systems). As for connectors, If you really want a shielded connection, aviation plugs seem to be quite popular, although they really work best with a panel/enclosure mount on the female end.
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Oh God… I just looked up the AMP superseal connectors… I have nightmares about those. Mainly because I used to do QA work with fare collection systems for mass transit. Guess how the power supplies are connected for the fare boxes? Thankfully, we had a power supply for each farebox…
Did you know they make wall-pluggable power supplies that have a 3-pin AMP connector on them? Actually kind of nice, since before then, it was a matter of wiring up the bus power cable to a cheapo Chinese power supply with a janky terminal-blockish plug. And faking the ground connection. Probably lucky I never fried myself or a $2500 farebox until we started getting those nice new power bricks.
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Other than Ethernet, the other popular ones we see are the aviation style ones like these:
They can vary a lot in quality. They are also pretty big, but especially if you’re mounting in a box, they can be quite sturdy. 4 pins + the outside for shielding.
Yeah, we had some of these, or similar ones, for some connectors on large automated trucks. They were a pain to disconnect/reconnect. They were certainly solid once they were connected thouigh.
Yeah, we were using them as connectors that were potentially on the bottom of public transit buses. Intensely secure. Not something I would treat as “quick swap”, although it would be better/easier than an end-to-end fully wired solution.
I am so enjoying reading this forum now. What people give is context to any question. That there are experts and experienced folks who might know something about every little detail is so cool for me. It’s a world that I don’t get to interact with much. But I really appreciate hearing stories like this. There are some things I have no idea about. I don’t know how important the detail is or not. So are connectors just a convenience thing or do they serve other purposes? The comments always help me understand why things are done a certain way.
I can’t contribute to the discussion, but it’s a question I have asked. I was planning on using Dupont connectors but the kit I ordered never showed up. So I just soldered everything up and used the connectors that came with the kit. I figured some day I would do something different to isolate the control box to be able to plug into the back rather than just go through into the board. But that really is a long term goal. It works great now and doesn’t lose steps. I used a stranded, 22/4 shielded security wire I got at Home Depot. I tried to source as much as I could locally. Had to go to Menards, Home Depot, Lowes, and a True Value to get all the various bits and pieces. I don’t have the shield correctly grounded, but again that is a stretch goal.
And speaking of context:
I already have those shielded cables but in front of my inner eye it would be nice to break the cable right before the motors and add plugs/connectors to easily install everything.
There have been some photos in a post where the cables had been soldered directly onto the PCB of the stepper motor what I see is a very clean way of attaching the cables.
But I was not successful in disassembling my motors without using too much force as I did not want to break them…
And so I thought that on the one hand I could pretty easily prepare some harness sets with connectors with the end stops and the motor cables and on the other hand the plain shielded cables I only head to measure in length and in the end just connect everything and that’s it.
But then there came the question about the right connectors…
I saw those already on eBay but I think those are too big, are they?
Maybe I’ll follow up on the RJ45 connectors and socket. The diameter of my cable should be around 8mm so it might fit into the plugs.
Or I just spare back the original motor cables and solder the shielded cable to them.
Me too! Although I often just want an answer to my question it is always a pleasure to read such stories and context! You can only become smarter with such facts. 
I just installed the jst-xh 2.54 connectors on my motors so if I ever have to test things at the controller it’s a direct plug in.
Do you have photos of it? There are motors already having those connectors but my motors have the cables soldered on their PCBs and it would be a question how/where to mount the jst-xh 2.54 connectors?!
Additionally I checked regarding RJ45 connection. Most plugs rate the current up to 1 - 1,5A only. I don’t know whether that is really applicable for our motors although I doubt we are running them at their limits all the time.
What about USB connection? Its mainly designed for 5V but maybe it might fit here as well?!
I think this is my motor side.
Wired the pigtail from the board for series.
Oh man. I haven’t seen the male connectors for those, except as through hole for pcbs. They don’t seem perfect though. It would be better if the shroud locked them together. hmmm.
Yeah, I’m going to design and print a clip for securing them.
On my last CNC build I used some 4 pin+shield audio panel-to-cable connectors with screw-on locks that I got cheap from Electronic Goldmine. I think they were originally meant for microphone cables. They have these as surplus from time to time.
CAT6 (23ga.) stranded is fine for Nema17 motors since the current is low enough that voltage drop is not a problem. Someone else probably mentioned this but if you do use ethernet cable make sure it’s stranded. Solid copper wire has a tendency to work harden and crack due to vibration.
That’s not entirely true. The problem is wire length, especially if people are running the X and Y motors in series. For my MPCNC I ran separate cables to each motor from individual drivers. Motor current is close to 1A but voltage is under 2V for typical motors. Over 15ft of Cat6, voltage drop is ~15% if using double wires for each (2 x 23 = 20AWG)
Voltage drop doesnt matter because the drivers will drive whatever is necessary (up to supply voltage) to reach the intended current. As long as the wires don’t overheat and start an electrical fire, which is impossible.
Okay. I’ve seen a lot of melted wires in my line of work (commercial electrician) so I tend to err on the side of caution. I ran 18/4 for my MPCNC. 
My longest cat6 wire is 10 feet. That’s the Z stepper wire, which follows my vac hose up to the ceiling and down to the center of my cutting area. I do double the wires though, both pairs of a color become a single color stepper wire.
That’s true if you’re not running X and Y motors in series, because if you are you have to include the length for both X motor runs together and Y.
