Dust hose grounding question

Hi all,

This is my first post so go easy on me😀.

So, I’ll get straight to it. Can I connect my dust hose grounding wire to the unused ground pin on the back of my control box. I’m too lazy to run a grounding wire and terminal to the nearest grounded object (overhead iron gas pipe), or put in a dedicated grounding stake and associated wiring.

I working on the premise that ‘ground is ground’, whether it’s a physical stake in the ground, metal piping that enters ground at some point, or electrical ground that all mains powered electrical items should be connected to. By virtue of the mains supply the X carve control box should be well grounded. I don’t think the connection would cause any ‘voltage/ amp issues, but I’m wondering if it would cause an electrical ‘noise’ within the Xcarve control circuitry.

Please, no guesses or opinions, just a yay or nay from any electronic wizards that are watching these posts.

Thanks in adavance.

The x-carve alone shouldn’t need a grounded vac line. What kind of vacuum are you using?

Other equipment that throws (blower motor) a large amount of chips very fast like a planer will make your hair stand up when connected to a vac and not grounded.

Just a regular shop vac hooked to the dust hose supplied with the 1000mm Xcarve machine kit. Designed specifically for the Xcarve, the dust hose kit comes with a grounding strap, so I assumed that Grounding is required.

In dry climates, the particles passing through a dust collection hose rub against the plastic in the hose and create a static charge. It’s just like scuffing your shoes across a carpet and getting zapped when you touch something metal. Most dust collection systems have a way to ground the hose and the unit just for just this reason. For large installations shops will have metal dust collection tubes just like your home heating ducts. Other shops will use flexible dryer hose made from plastic and a wire coil. In that case the wire in the dryer hose is attached to ground. Still other shops will use PVC drain pipe or all plastic vacuum hoses. In that case many shop owners will wrap a bare wire in a spiral down the length of the hose and connect that to ground. Doing this will slowly drain away the static charge so that you won’t get zapped when you touch the hose.

Your shop vac is probably grounded. I wouldn’t worry too much if your collection hose is short. If you don’t notice static build up I wouldn’t worry. If you are getting a lot of static at the collection hose, you might want to pursue the grounding.

You don’t want to run the ground to the back of the controller. Static charges are high voltage and you don’t want to send that into the controller ground. I connect a banana jack to the ground wire and plug it into the ground on the duplex jack the controller is plugged into. Using a banana jack makes it impossible to plug it into the hot lead. 40 years experience working communications on microwave sites. I have replaced many parts blown up by lightning.

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I think it’s OK, but maybe not the best. The (X-Controller and the Arduino/G-shield Controllers’) ground terminals, are wired to the line cord receptacle’s ground terminal, so any discharge in the vacuum hose ground wire should harmlessly discharge through the line cord on the controller’s power supply. I actually have one of the three machines in my shop set up that way. As far as getting zapped by the vacuum hose, I have no worries about the set up, but it still makes me worry about the controller. I think there’s a better option.

I’ve modified one of my vacuums for dust collection. I tore into the motor housing and found a likely spot to put a machine screw. I jumpered the machine screw to the green wire on the vacuum’s line cord (there was a nice big green screw terminal inside the motor housing switch enclosure. This gave me a nifty screw terminal. I wrapped bare stranded wire around the vacuum hose and connected one end of that to my groovy little grounding terminal.

Bona Fides: I live in a high mountain desert. I’m not worried about dust explosions, but the vacuum hose used to zap my students a lot. I maintain 3 x-carves, two in the school shop and one in a community maker space. One X-Carve was modified and tuned by an engineer friend, a field engineer with a crap ton of real world experience, and he’s the one who ran a ground wire from the dust shroud, through the drag chain and connected it to the ground terminal on the power supply for the Arduino G-Shield controller. It’s been that way for three years and worked fine with no problems or static zaps. The ground terminal on both the G-Shield set up and the X-Controllers is wired directly to the ground terminal for the line cord receptacle, so there should not be a problem.

Oh and by the way, NEC (250.52 B 1) says ix-nay on using gas piping as a grounding terminal. I’ve been similarly tempted. Courage my friend be not lead into temptation. Gas pipes are (supposed to be) BONDED to the ground system, but they are not “grounded” the way the ground terminal on a properly wired receptacle should be. Although the gas pipe should be at ground potential, there may be resistance between your location on the pipe and the ground terminal in your service panel, meaning that there CAN be an electrical potential between a bonded gas pipe and the actual ground potential,

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Are they?
In terms of grounding mixing DC GND (Common GND) and AC GND (Earth GND) isnt desired, they should be seperate.

I thought static charges only became a problem if you allowed them to ‘build up’. If the hose is constantly grounded, by definition, you will not get a high voltage static charge developing.

Thank you for your response. It’s the only one that’s come close to answering my specific question - and thank you for the heads up on the gas pipe issue. I have decided to remove all doubt, discussion and conjecture by going the ‘4ft grounding rod smacked into the ground’ route. I am running a dedicated grounding wire from the stake to a terminal block in the center of the workshop. I am planning a full dust collection system at some point, so I may as well start from the ground up😀

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Harry that would be true if the hose has a metal sheathing as part of it. Mine is plastic and I used a hose clamp around it to connect the ground wire to. Static has to build up to make it to where the hose clamp before being discharged. Even still best practice is always run grounding external of equipment.

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Hi Dennis,

I’m just an anonymous moron on the internet, but I’m not sure your solution is a safe one, for the same reason that gas pipes are not good ground terminals. Soil conditions can create a voltage gradient between the ground in your service panel and the ground stake you install in another location. Grounding remains a mental challenge for me to understand and much that is in the codes conflicts with my intuition and natural fear of poking at electrical wires. But I’ve got an idea that the NEC would require you to bond it back to the building ground at the service panel though I cant cite a specific section.

Assuming you have properly wired 3 prong outlets, the ground wire in the line cord of your vacuum should be adequate, as should the ground wire in the line cord for your X-Carve. As far as I can tell/see, the chassis of both types of controllers are bonded to the ground wire in their line cords.

Consider spending 15 bucks on one of the DIY electrical wiring for homeowners books out there. Find one with a good electrical theory section. Black and Decker published a pretty good one a few years back. DeWalt published a more expensive one aimed at contractors and apprentices. You may not want to rewire your house, but they do explain the rationale behind many wiring practices.

I’ve had mine grounded to the same spare earth on X controller for 3 years never had an issue. If there was great danger and massive static discharge possible from the hose of the dust collector - I’m sure Inventables would suggest you get and electrician to install it.