How To Ground Your CNC Explained (This Also Covers Using Shielded Cable Properly)

[@alexday2373]

Dude, awesome. Didn't think i would sit through a 22min clip with no pictures. Need more stuff like this. Cheers

[@corvetteguy50]

Alex, Thank you for your support. I suck at being entertaining :), but my channel will help you learn what you need to know about your CNC robots electronics. Have a Happy New Year! Vince

[@alexday2373]

@@corvetteguy50 What shielded wire would you recommend for a nema 23 setup with rated volts 2.45 and rated amps 3.5. The wire is not the cheapest and I know that you know, what would work good haha. I just cut all the wiring out of my home built CNC to start all over again..... Also, if I shield the wiring from the motors, should I also shield the wires to limit switches? Cheers

[@corvetteguy50]

@@alexday2373 Shielded cable is yo be used throughout the entire system to assure you mitigate any possible EMI penetration Here's the cable to use for your steppers if you want to build your own www.ebay.com/itm/142355188071, here's the cables to use if you want them prebuilt www.ebay.com/itm/133300288430and here's the cable to use for your limit switch applications. www.ebay.com/itm/132575648256 Thank you, and have a Happy New Year! Vince

[@alexday2373]

@@corvetteguy50 Thanks again mate, greatly appreciated. 2 questions.... Should every cable be shielded, including power supply to drivers and drivers to control module. And you say to run the earth lead from the cables to the chassis, only at one end to avoid creating a loop. So assuming that the machine has a good earth (3rd plug in the wall socket), than it should not matter where it is in theory, as long as it goes to the chassis?

[@corvetteguy50]

@@alexday2373 All signal cables should be shielded. Power supply cables aren't required. Details matter with grounding this video covers the required Ohm rating for a robot to be considered grounded. kzbin.info/www/bejne/Zp2VhHysesp_hMU Thank you, and have a great weekend! Vince

[@IEraiderfan]

Vince, thanks this is one more great video I learned I have been doing it wrong with my shielded cable thanks for the tutorial, stay safe. 👍🏼

[@corvetteguy50]

You bet Lou! Glad to help! Thank you, Vince

[@29Gleisson]

Amazing Video, simple terms and straight forward, you really know how to pass a message across, concise and organized. Easy to learn from you. Thank you.

[@corvetteguy50]

29Gleisson, thank you for your support. I really appreciate it, and the kind words. have a great weekend! Vince

[@corvetteguy50]

MrJ,Your correct about using a grounding rod, as being the most definitive source for a proper ground, but for most of my clients it may not always be an option. The third prong method provides the best coverage without using a grounding rod.If however anyone reading these comments is able to install one please by all means install one.Thank you again for your support MrJ. :)Vince

[@ukie1242]

Thanks for the excellent video. You have answered some of the questions I had about properly grounding shielded wiring.

[@corvetteguy50]

Nicholas, thank you for your support! I'm glad to have helped. Have a great weekend! Vince

[@mikethomaseric]

Hi Vince I contacted quite a few weeks back your information was invaluable this video simplified what I needed to do. Have my machine running perfectly. Thankyou

[@corvetteguy50]

Yes sir. It seems sometimes like pulling teeth to get a simplified explanation on grounding components properly, but its actually very simple to do. I'm glad the video did its job for you, and others. Take care, Vince

[@pw3111]

Thanks for a fascinating video. Just a question - if I’m using a metal cabinet, can I earth the wire shielding to the cabinet itself and earth the cabinet to the power supply earth wire?

[@corvetteguy50]

Thank you for your support. Yes, you can do that, but in best practice a "Star Point Ground System" will allow for termination of all shield drains in a more organized fashion. Here's me covering it in a clients pro-build system I did kzbin.info/www/bejne/fprOaIaioL1of9U Thank you, and have a great weekend! Vince

[@pw3111]

@@corvetteguy50 Thanks. If I’ve got this right, I connect all DC grounds to a star single point ( eg. one COM/GND terminal from each power supply, Arduino UNO GND terminal, fan GND wire etc) BUT I DO NOT connect that star point to the power supply 240v earth terminal. However all shielding earths should be connected to another star point and that star point IS connected to mains earth.

[@corvetteguy50]

@@pw3111 All grounds period should be going to the Star point ground. (COM, and V- aren't grounds.) Thank you, Vince

[@theveryboredperson]

Great video! So just to be clear, this is where I always get lost.... I have a 24v PSU (input/ Output power) and a 36V PSU (stepper Power). Spindle is a 500w Ryobi AC Trim Router. all running in cable chains together, input wire all shielded, stepper control all shielded, spindle power unshielded. As long as my wall outlet ground is earth grounded (haven't poked a tester in it yet), can I run a jumper to my 120vac ground to a ground block and terminate all of my shielded cable to it? I have always been afraid of this, thinking it may back feed 120vac to my components in the event of a line short. This is good as long as my 24vdc and 36vdc negative posts aren't grounded to the earth ground? right now I have my shielding grounds terminated to the component grounds (negative Terminals), shielding step/dir signal negatives terminated together from Breakout board to Motor drivers (BOB end Only), my shielding from motor Drivers to motors isn't terminated yet because it didn't sound like a good idea to terminate at BoB grounds. Is it right unhook all of these shielding cables and terminate at the 120vac Earth ground, not tied to any components negatives? Chassis is extruded aluminum it also? Sorry and Thanks

[@corvetteguy50]

Chris, thank you for your support. the answer to your questions is below. Great video! So just to be clear, this is where I always get lost.... I have a 24v PSU (input/ Output power) and a 36V PSU (stepper Power). Spindle is a 500w Ryobi AC Trim Router. all running in cable chains together, input wire all shielded, stepper control all shielded, spindle power unshielded. The spindle your suing should be using a double shielded cable in best practice to mitigate both EMI frequencies. As long as my wall outlet ground is earth grounded (haven't poked a tester in it yet), can I run a jumper to my 120vac ground to a ground block and terminate all of my shielded cable to it? In best practice a ground buss bar is used to split the ground terminal to allow the ground to be split for connections to support all shield drains. I have always been afraid of this, thinking it may back feed 120vac to my components in the event of a line short. This is good as long as my 24vdc and 36vdc negative posts aren't grounded to the earth ground? Back feed is usually never an issue as all power supplies Chinese or otherwise are all fuse protected. right now I have my shielding grounds terminated to the component grounds (negative Terminals), shielding step/dir signal negatives terminated together from Breakout board to Motor drivers (BOB end Only), my shielding from motor Drivers to motors is terminated yet because it didn't sound like a good idea to terminate at BoB grounds. Is it right unhook all of these shielding cables and terminate at the 120vac Earth ground, not tied to any components negatives? Chassis is extruded aluminum it also? Please review my pro grade Gecko Raptor build here, and you can see best practice for grounding using a ground buss, and Star Point grounding system. kzbin.info/www/bejne/fprOaIaioL1of9U Thank you, Vince

[@theveryboredperson]

@@corvetteguy50 Thank you. Video was very informative and let me know exactly what I need to do, Especially my shield grounds from the motor cables. That Raptor controller box is beyond awesome!

[@corvetteguy50]

Thank you sir, I certainly appreciate it. I'm glad I could help. Vince

[@DennisTang]

Good information, i have been searching for info on this for a while. You have simplified it for me.

[@corvetteguy50]

That was my goal. Grounding is required on every machine, to eliminate any possible EMI issues. I'm glad you enjoyed the video. Take care. Vince

[@MrJTJINX]

Great informative video, i have just one observation to make. The use of your AC power outlet ground pin for earthing EMI in machines. i would recommend the use of an earth rod away from the outlet, two reasons really. You don't want the EMI introduced into a mains installation (possibly having a poor earth already) and you don't really want to mess with the mains system in your home etc. If you were to have an electrician test your earth loop on your mains supply and run a CNC plasma at the same time - i'm confident he will go and put his meter back in his van and refuse to test. These things are hugely noisy. When you see a hollywood film where you see electricity tracking along walls, metalwork, desks etc EMI if you could see the noise would look just like this, kind of Frankenstein - that.s what we are grounding stray wiggly's. Filtering - most of our problems become visible as we are using PC's/Laptops to run our equipment the machine crashes predominantly as the operating software crashes. Adding a mains filter and using screened communication leads helps a great deal. The Earths and screens attached to the machine work best individually wired (star wired) to the earth point. Daisy Chaining just passes the EMI from one surface to another increasing the massive aerial you are building. Dissipating EMI from each part directly to ground Ensures a good solid dispersal point for that item/part of the machine. Copper Earth Rods, umm where to begin. These are not magic wands you bury and forget, depending on soil type you may need either a 3 foot or 6 foot copper rod. I have a particular issue with the ground drying out where my rod is located so i have to water it occasionally like a plant. I am far from being knowledgeable like corvetteguy50 but he is definitely accurate in what he says. We are not taught much about grounding noise and its a bigger problem than we might think. There are standards which must be adhered to when manufacturing domestic appliances but they are designed to minimise EMI to acceptable levels nor eradicate it, If we Import a cheap Asian power supply to run our equipment then our domestic supply can already be humming by the time we try to run processor controlled equipment. I have a set of spot lights above my bench which cause my HiFi to hum when they are both on together, both items are European CE rated and probably both Asian in manufacture. Hopefully i have added something useful to the conversation. At least if someone adds to my comment or rips it apart we all benefit from this exceptional discussion.

[@Jay.perez1]

Thank you for the excellent information. I understand the basic concept and reasons for earth grounding all the components. Then I go out to the machine ... I've converted a small Unimat lathe to CNC using the Zyltech kit with an Ardunio Uno and Grbl shield. I'm having what I believe are noise related issues and want to start out by just properly grounding everything. The problem I'm having is understanding what is the correct point on the Ardunio/Grbl boards for the earth ground. My power supply has three connections each for the + & - 12 VDC power to the circuit board and has the usual two wire A/C with earth ground connections. If I test it with an ohm meter the earth ground is connected to the metal housing. However, there's no continuity between these and the 12 VDC V- terminals. I've connected the 12 VDC power to the Grbl shield but there's no obvious place to connect the earth ground. If I meter the boards they have multiple pins that say GND but these are all connected back to the black 12 VDC V- power terminal. Can you tell me where to attach the earth ground on the Grbl board ? (I'm assuming you don't connect earth ground to the V- loop.) I've looked all over the Internet and haven't been able to find the answer to this basic simple question. Thanks in advance for any help you can offer. Jay

[@corvetteguy50]

Jay, The reason you haven't found an answer online to your question is your essentially trying to ground a bare circuit board which is typically not required if its mounted in a proper electrical enclosure which will act as a "faraday cage" Do you have the unit installed in a metal electronics enclosure? If you do it, and ground the enclosure you will then have the proper level of protection to isolate the unit from EMI. What problems are you encountering that you feel are EMI related? Please use my email to respond as its a better way to reach me ([e-mail]) Thank you, Vince

[@Jay.perez1]

Thanks for the quick response and comments Vince. I'm responding publicly to your question for the benefit of others following your thread and will also contact you via your email address. The biggest issue I'm currently having is the losing the COM3 connection. I have to disconnect the USB cable and plug it back in to reestablish it. I'm mostly using the GrblGru software on my Windows 7 PC to operate the lathe. The software is also crashing fairly often but I'd like to resolve any EMI issues before investigating whether the code is causing the crash. No, the Grbl controller is not yet installed in any type of case yet. I'm also not currently using any shielded cables yet as the only wires going from the controller are the two sets of four-wire cables to the two stepper motors. (Can/should these be separated and/or shielded ?) The spindle motor on the lathe is what looks to be the type you'd find on an old sewing machine with the carbon brushes. I'm sure this is very noisy and know for a fact that turning this on and off can cause the software to freeze. I've removed all the limit switches for now to eliminate them as a possible source of the problems and have physically separated all the cables from each other to try and minimize cross-talk. Per my first posting I'd like to start by taking care of all the basics which seems like good earth grounds. Does that sound right ? Thanks again. Jay

[@corvetteguy50]

Jay, The first thing to start with is utilizing shielded cable on everything on the system. The entire system is reflecting instability which is why I recommend an electronics enclosure, and shielded cables for every component. Once that's completed providing an earth ground is as simple as running a lead from the third prong on your typical 120v wall outlet to a terminal splitter to allow all your shield drains from the shielded cables to connect to it. Thank you, Vince

[@Jay.perez1]

corvetteguy50 Thanks for the advice Vince. I'm sure you're familiar with the typical 4 wire cables from the drivers to the stepper motors on the Grbl controllers. Each end has the plastic connectors that plugs into the pins on the board. (.100" spacing.) Do you sell these cables with shielding ?

[@corvetteguy50]

Sorry I don't, as they use plastic connectors. Thank you, Vince

[@bengrobben2582]

so if i get this right, the drain wire and the shieldwire both on the ground? thanks

[@corvetteguy50]

Hey Ben, Thank you for your support. The shield drain, and shield wire is one in the same, so your correct. Thank you, and have a happy Thanksgiving! Vince

[@Jay.perez1]

Hey Vince, Thought I'd give you a quick update on my CNC Lathe. As you recommended I ran a ground wire to the body of the lathe last night. Just doing that seems to have made a big difference. I ran a toolpath and while it was running I kept turning the spindle motor on and off. It probably took over a dozen tries before the software locked up and crashed. Per my email I'm interested in buying the grounded aviation connectors and shielded cables with the ferrite rings. Thanks again for the help. Jay

[@Super73VW]

I am having an interesting problem with my DIY CNC router I built. I have multiple floating points due to each axis riding on non-metallic wheels. I already had to add a ground wire to my spindle, so my Z axis will be grounded due to the spindle body now being grounded. This leaves my X axis floating still. I want to avoid ground loops, so I am wondering how I should ground my chassis. Ground each axis with a screw and 20AWG wire then each to a star ground, and all drains to the star ground point?

[@corvetteguy50]

Jon, Thank you for your support. I would do as you wrote, but grounding each axis individually isn't required as the chassis I'm assuming is a metal frame in which case attaching a star ground to a central point, and connecting the earth ground from a grounding rod, or verified earth ground from a wall socket will accomplish grounding the chassis as a whole. If however your chassis isn't utilizing a metal frame grounding each point the way you described is the way to go. Thank you, Vince

[@Digital-springUk]

This is great information man, thanks for taking the time to do it. I'l putting in limit switches using shielded at the moment, but this now makes me want to go and ground the chassis, which I will do tonight. One question if I may? I have the stepper motors running back to the board, they have a lovely connector on them, to connect up to the motor. I am not sure I could fine those connectors again, so is there a shielding that you can apply to the wires, that you can then earth ground? Also, I was wondering. I have a big old earth cable in my workshop, that runs from the distribution board, out of the wall and into a spike in the ground outside. If I were to tap into this and run a cable off it, could I have all my ground wires terminated into that? Would that give me the ground I need? I cant see why not, but I am a noob to CNC and more a woodworker than an electrician. Thanks in advance

[@corvetteguy50]

You can, and should use your earth ground rod if you have one available. The best way to shield a cable without destroying the end would be to apply copper tape around it, but Its a double edged sword. You'll lose most of the flexibility from the cable if you correct them this way. The benefits of shielded cable can't be emphasized enough if possible I highly recommend changing them to shielded ones, and properly grounding the system. Its tedious, but the end result will be well worth it. Thank you, Vince

[@Marekvastopa]

People tend to underestimate earth importance. Thanks for educational video.

[@corvetteguy50]

You bet, and thank you for your support.Vince

[@jessesilver]

What's your POV on whether to ground the shield on the spindle side or the vfd side or both? I've heard lots of arguments about this 😊

[@corvetteguy50]

Jesse,Ground the unit on either end, but only on one side. This is to prevent ground loops. If you don't ground the unit properly the little EMI gremlins will usually be at work on your system. Proper cable choice is essential as well, and that's why I sell, and use 16awg double shielded for bullet proof protection when grounded as discussed above.Thank you,Vince

[@darshanaacha6469]

I did the first part with gold plated soldering terminal on the frame and the earth grounding on my wall plugs. I just got mine 1 week ago and i am a complete newbie to cnc. safety is very important for me so the next thing i want to do is change all the cables to shielded cables, this is where i am not sure how to do it. Do i just buy high quality shielded cables and replace all the wires or only some specific wires need to be replaced? plus how do I ground the black controller box?

[@corvetteguy50]

Darshan, Thank you for your support. You want to use shielded cables when their carrying any signals that could be contaminated by EMI. Ground the controller using the method outlined in this video. kzbin.info/www/bejne/mXfVg3iBd5Kfaq8 Thank you again, Vince

[@darshanaacha6469]

@@corvetteguy50 thank you so much. very informative and helpful video.

[@corvetteguy50]

@@darshanaacha6469 You bet :) Thank you, Vince

[@Colth451987]

So I've laser cut myself a wood enclosure for my DIY CNC. How would this change things? Thank you!

[@corvetteguy50]

Colth, thank you for your support. An electronics enclosure for a CNC controller should always be metal to allow for proper EMI shielding under best practice. The enclosure will act as a "Faraday Cage" to protect the system from interference. Another huge safety factor to consider is wood is flammable, and should never be used where a short, or spark could ignite in proper conditions. Thank you, Vince

[@jp8479]

Do you ground both ends of cable or just the side at the enclosure box? For motors, spindles. What about inside the box between controller and drivers, step,dir

[@corvetteguy50]

JP, thank you for your support. You ground ONE end only to prevent ground loops. This is the same for all components your grounding. The enclosure your using for your electronics should also be grounded as well, so when you mount your ground bar to its base any shield drains run to it from your electronics is grounded. I prefer to have my grounds run all to my electronics enclosure. The spindle cable should be grounded at the VFD. The CNC chassis itself should also be grounded following the Ohm readings quantified in this video overview. kzbin.info/www/bejne/Zp2VhHysesp_hMU Thank you, Vince

[@ibreakstuff815]

I am having a hell of a time tracking down the source of my signal noise. I have gecko 340 drives for my servos, and they worked for 10 years with no problems. A week ago my z x and y were way off during a program run I have done hundreds of times. My z actually plowed down and destroyed the endmill and my work. After replacing my 5 volt wire with a heavily shielded wire I thought I had fixed the problem, but during testing, it appears all 3 servos are still drifting. They all move at 0.01mm per second. All of them are turning the same direction. My signal cables are all shielded and ground to the metal of the milling machine. The only cable that I am unsure about shielding on is the parallel port cable. On testing though, even with the PP cable completely removed from the servo controller, and the computer powered off, the servos still move when the spindle is on. The spindle speed determines the amount of drift the servos move, so I know it has got to be signal noise from the spindle. I tried wrapping foil around the power cables going from the spindle motor to the spindle power supply. Nothing seems to solve this problem. Gecko advised me to turn the gain full clockwise on all the 340s, but that did nothing. I tried using debounce on Mach3, also no change. I am completely lost and i've been down for 7 days now with no way to use the machine. Any suggestions?

[@corvetteguy50]

Your issue is a very common one, and I suggest replacing the spindle cable with my double shielded robotics cable here www.ebay.com/itm/CNC-Spindle-Cable-10Ft-16awg-4-Lead-With-Drain-Double-Shielded-Robotics-Grade-/142036230702?ssPageName=STRK:MESE:ITThis cable is designed for automation, and will guarantee that will make the spindle noise vanish as long as the machine is grounded properly according to the video. You also will want to document your troubleshooting of what you've done to solve the issue using this template system used in full scale manufacturing I've provided you here.kzbin.info/www/bejne/a5vCqHyEh5h8fcWJsing the components, and cable combined with the tools I provided you will yield the best results for you solving the noise issue, or any other problem your encountering on your own. A problem that just reflects itself after a decade of use is usually some of the hardest to identify. These will simplify the process. Take care, Vince