Ground Rod Location

[happymachinist]

Not sure if this is the right place to put this but it is electrical none the less.

I recently moved and am looking to get my powder coating hobby back up and going.

To receive the best results it's recommended to have a dedicated ground rod to ground the parts and or rack that my parts will hang from while coating.

I was not permitted before to install my own ground rod (landlord) in my previous shop. I ran a cable and clamped it to a pipe that went into the ground with so so results.

My question is: Can I sink a ground rod inside the shop? The concern I have read is that the earth under the slab will be dry since it doesn't receive any moisture from mother nature. I can put it outside but would prefer one less hole through the wall, hence putting it in the corner.

I plan on driving an 8' ground rod as deep as possible with room for the clamp and wire to attach.

Thanks!

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[wyliesdiesels]

Where did u read that u needed a ground rod?

The main purpose of ground rods is for grounding lightning strikes...

 

[happymachinist]

Where did u read that u needed a ground rod?

The main purpose of ground rods is for grounding lightning strikes...

It's well documented on powder coating forums.

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[Maverickv46]

Personally, I ran my ground wire through the wall to the outside of the shop and drove a ground rod there.

I have read about instances where people drill through the slab and drive the rod right next to the booth. They enjoyed being able to pour water on the rod without having to leave the shop.

IMO I did not want to put a hole in the slab and introduce moisture under. Thinking about the reasons why an extra hole in the wall might not be desired, it seems that those consequences only multiply when they are in relation to the slab.

 

[sberry]

It's well documented on powder coating forums.

What do they say about it then? What people think about grounding is often quite interesting.
I don't know anything about powder so only assume it is a charged machine with isolated secondary something ,,, they could want it all the same potential as the ground it all sits on, maybe reduce step potentials to keep the shite from going everywhere?
No matter what its likely the best is still on the electric service.

 

[wyliesdiesels]

It's well documented on powder coating forums.

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And what is the purpose?

 

[Maverickv46]

Powder coating is an electrostatic process where the gun places a positive charge on the powder being sprayed. The part to be coated is then negative and ideally with as little resistance to ground as possible. Utilizing the shops electrical system ground is physically possible, but with greater resistance than a dedicated ground rod.

During the coating process, you are utilizing up to 100kV to charge a very fine powder. There are build ups of charge to deal with, back-ionization, and other factors that compound the process. In order to get the best results with single and multi coat jobs, the least amount of resistance to electrical flow from gun to ground is desired.

Similar to air flow in pneumatic tools. 1/4" coil hose will most likely make your impact spin, but you really need the large hose to get performance.

 

[Lassen Forge]

Drill a hole (or holes) in the slab, install the ground rod(s), then backfill the holes with sack-crete. We did that at a radio transmitter site (where grounding issues are more critical than powder coating), and never had any problems. If you want to isolate the ground rod from the slab (with 100kV potential you may want to), you can coat it with Silicone Insulating sealer before the sack-crete.

 

[Stuff]

Sounds more like an urban myth. Electrons (and holes) follow paths back to the source. Probably installing a ground rod simply gets a better connection than just using an alligator clip.

This shows the electron flow and doesn't go through a ground rod. They show equipment grounding for ESD protection only. http://emanuals.nordson.com/finishing/files/Powder/tctt-06-3881.pdf

 

[sberry]

Who ever wrote some of that needs to rephrase it or take another class.

 

[Elginz]

It seems there are not a lot of people here doing powder coating. I don't either it is just interesting. Is this a floating slab or deep footings? You should reach some moist earth with an 8' rod minus the slab and what is left above the slab. Personally I would think a wire though the wall would be better. In the corner under the down spout.

 

[wyliesdiesels]

Powder coating is an electrostatic process where the gun places a positive charge on the powder being sprayed. The part to be coated is then negative and ideally with as little resistance to ground as possible. Utilizing the shops electrical system ground is physically possible, but with greater resistance than a dedicated ground rod.

During the coating process, you are utilizing up to 100kV to charge a very fine powder. There are build ups of charge to deal with, back-ionization, and other factors that compound the process. In order to get the best results with single and multi coat jobs, the least amount of resistance to electrical flow from gun to ground is desired.

Similar to air flow in pneumatic tools. 1/4" coil hose will most likely make your impact spin, but you really need the large hose to get performance.

Ok so the electrons are flowing from the work through the slab, into the ground rod, through the GEC to the panel, and through the EGC that connects the panel to the machine. Thats gonna create more resistance than if u just grounded the machine to the work like a welder.

Definitely an urban myth.

As said above, the electrons flow back to the source. Is the earth the source? Absolutely NOT. The electrons need to get back to the machine. Thats why it doesnt make any sense to use a ground rod. All they need to do is flow back to the machine.

Heres a great article on a subject similar to this that most everyone confuses:

http://www.electriciantalk.com/articles/the-confusion-of-the-term-grounding/

 

[happymachinist]

Personally, I ran my ground wire through the wall to the outside of the shop and drove a ground rod there.

I have read about instances where people drill through the slab and drive the rod right next to the booth. They enjoyed being able to pour water on the rod without having to leave the shop.

IMO I did not want to put a hole in the slab and introduce moisture under. Thinking about the reasons why an extra hole in the wall might not be desired, it seems that those consequences only multiply when they are in relation to the slab.

I can understand where you're coming from. Outside is little more than a foot or two farther. A hole in the corner of the slab would be a good place for a crack to start.

What do they say about it then? What people think about grounding is often quite interesting.
I don't know anything about powder so only assume it is a charged machine with isolated secondary something ,,, they could want it all the same potential as the ground it all sits on, maybe reduce step potentials to keep the shite from going everywhere?
No matter what its likely the best is still on the electric service.

What they say is the less resistance to ground the better. My gun is a cheap hobby gun I used it for a time without any extra grounding relying only on the outlet and service it was plugged in to, and it worked.

When I added an extra wire from a pipe in the ground second coats got a little easier, and it seemed like less wasted powder on the ground. This is why I want to try a dedicated rod.

Powder coating is an electrostatic process where the gun places a positive charge on the powder being sprayed. The part to be coated is then negative and ideally with as little resistance to ground as possible. Utilizing the shops electrical system ground is physically possible, but with greater resistance than a dedicated ground rod.

During the coating process, you are utilizing up to 100kV to charge a very fine powder. There are build ups of charge to deal with, back-ionization, and other factors that compound the process. In order to get the best results with single and multi coat jobs, the least amount of resistance to electrical flow from gun to ground is desired.

Similar to air flow in pneumatic tools. 1/4" coil hose will most likely make your impact spin, but you really need the large hose to get performance.

Good explanations, and faraday issues...they **** too!!

Drill a hole (or holes) in the slab, install the ground rod(s), then backfill the holes with sack-crete. We did that at a radio transmitter site (where grounding issues are more critical than powder coating), and never had any problems. If you want to isolate the ground rod from the slab (with 100kV potential you may want to), you can coat it with Silicone Insulating sealer before the sack-crete.

Good info on isolating the rod from the pad itself. I hadn't thought about that potentially being an issue.

It seems there are not a lot of people here doing powder coating. I don't either it is just interesting. Is this a floating slab or deep footings? You should reach some moist earth with an 8' rod minus the slab and what is left above the slab. Personally I would think a wire though the wall would be better. In the corner under the down spout.

The more I think about it if I install a rod a simple hole through the wall is making more sense. It's no farther than where I planned on putting in the corner.

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[happymachinist]

Ok so the electrons are flowing from the work through the slab, into the ground rod, through the GEC to the panel, and through the EGC that connects the panel to the machine. Thats gonna create more resistance than if u just grounded the machine to the work like a welder.

Definitely an urban myth.

As said above, the electrons flow back to the source. Is the earth the source? Absolutely NOT. The electrons need to get back to the machine. Thats why it doesnt make any sense to use a ground rod. All they need to do is flow back to the machine.

Heres a great article on a subject similar to this that most everyone confuses:

http://www.electriciantalk.com/articles/the-confusion-of-the-term-grounding/

I can't seem to get your link to work on my phone at the moment, might have to try it at home on the computer, or open the forum in browser and not Tapatalk.

You're obviously far more versed in electrical education than I am. In the desire to install a ground rod, I'm just following the advice of other coaters who have been coating a lot longer than I have.

They claim adding a ground rod has improved their process and I have no reason to doubt them, they have taught me quite a lot on the ins and outs of coating.

Just to clarify, if I do install a ground rod, it is a stand alone entity just for powder coating. It will not return to the panel, it hooks directly to the parts or steel racks that the parts hang from. Basically dirt to parts via a 4ga wire.

Since you seem well versed like I said above, maybe give "powder coating ground" a Google to see where I'm coming from...that way you won't think I'm TOTALLY nuts.

I'll give your link a read.

Thanks everyone for the replies!



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[mm08822]

When you added the extra wire from part to pipe in ground, created an additional path back to the unit. This lowered your overall resistance between unit and part, even though that new path was full many poor connections.
I reccomend you get a larger "grd" wire and better work clamp and use it to replace the little cheapie alligator clip on the unit now. Also, the parts just hang off of a grounded "hook". That right there is a poor connection. So if the part allows for a clamp connection directly, i would use that. I dont see this as any different than a welder and its ground (return) connection back to the unit.

 

[Maverickv46]

I think there was a bit of miscommunication here. Keep in mind, I am a mechanical guy with only a bit of electrical under my belt

The electrostatic process is not intended to be a flow of electrons, aka current. Instead it is about creating an electrical potential between the fluidized powder being sprayed and the part to be coated. The less resistance between ground and the part, the stronger the attraction of the charged particles to the part, leading to less overspray, less faraday problems, more even coating, and less back ionization. The tip of the gun is a high voltage, low current source, and the operation does not rely on a flow of electrons back to the unit.

 

[matt_i]

If you want a better ground, build a Ufer ground where you excavate, drive a rod in the hole and then surround it with poured concrete. More or less, the concrete has a better "interface" with more surface area to the earth than the small round rod itself. One can google Ufer Grounds to learn more. Sometimes integrated into the rebar "cage" of a foundation.

 

[sberry]

Is there a lead from the machine to the part being sprayed? I bet money this earth ground doesn't have much to do with it except for reducing step potential. Again I only read a paragraph of what was posted but the author has some of it confused before he even states. It didn't copy and paste correctly and probably with good reason, they may not want to be quoted.
I havnt read it all but am with wylie so far.

A ground electrode has nothing to do with clearing fault current in an electrical distribution system. In addition, a grounding electrode system adds little to nothing to the operation of equipment in a facility.

Refer to Figure 1. All electrical circuits need a complete path for current to make its way back to the source (circle=circuit). Electrostatic spray guns emit current (ions) and therefore require a complete circuit. Some of the current emitted by the spray gun is attracted to the spray booth, but most is attracted to the grounded parts moving through the booth. The current attracted to the parts flows through the part hangers to the conveyor and to the building ground, back to the controller through a ground braid and back to the spray gun through the gun driver board. The current attracted to the booth is returned through the booth ground to the controller and back to the gun.

 

[Maverickv46]

Many machines offer this lead from the control unit to the part. 90% of coaters do not use this lead and instead use the ground rod connection.

 

[sberry]

Many machines offer this lead from the control unit to the part. 90% of coaters do not use this lead and instead use the ground rod connection.

So they don't follow instructions?

 

[APEowner]

I think there was a bit of miscommunication here. Keep in mind, I am a mechanical guy with only a bit of electrical under my belt

The electrostatic process is not intended to be a flow of electrons, aka current. Instead it is about creating an electrical potential between the fluidized powder being sprayed and the part to be coated. The less resistance between ground and the part, the stronger the attraction of the charged particles to the part, leading to less overspray, less faraday problems, more even coating, and less back ionization. The tip of the gun is a high voltage, low current source, and the operation does not rely on a flow of electrons back to the unit.

Hmm. At first I thought that the ground rod thing was nonsense but this sort of make sense to me. So, the idea of the ground rod is that the voltage potential between the gun and the part can be larger? Or, in other words, the ground clip from the machine goes to earth ground through the power cord, building wiring and breaker panel while a ground rod eliminates all of that?

 

[Maverickv46]

You got it! Works much better with the ground rod, and multi coats become much more pleasant.

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[CudaChick1968]

I specialize in multi color custom one offs, some with six or more colors. I rarely use my ground rod.

 

[Maverickv46]

Out of curiosity, are yours layered colors mainly, or masked areas?

Also, what gun are you using nowadays?

 

[CudaChick1968]

Yes. Lol ... you aren't the first to ask and won't be the last, but 17+ years of trade secrets aren't going anywhere.

I still have my old workhorse first generation HyperSmooth. The ones they have now can't compare in my opinion.

 

[happymachinist]

Is there a lead from the machine to the part being sprayed? I bet money this earth ground doesn't have much to do with it except for reducing step potential. Again I only read a paragraph of what was posted but the author has some of it confused before he even states. It didn't copy and paste correctly and probably with good reason, they may not want to be quoted.
I havnt read it all but am with wylie so far.

Give this a look:

http://www.parkerionics.com/knowledge-center/



(Quoted from the link above)
I’ve heard that grounding parts is important, but why is that?

We are truly ground fanatics. It is our opinion that proper grounding of parts to be coated is the single-most important part of successful powder coating. While resistance to ground of < 1 MOhm is defined as necessary for powder coating, this is a personnel safety specification only. The optimum resistance to ground for powder application is zero (0) ohms, i.e. direct contact with ground. Charged powder particles are looking for earth ground to give up their extra ion and return to their neutral state. Any less than zero (0) ohms to ground compromises this ability.

What do you recommend for a ground circuit?

We believe that the proper ground path for a conveyorized coating line is as follows; it starts at a grounding rod sunk into moist soil (preferably located at the drip line of the building) 8 – 10 feet down being connected to an 8 ga. stranded copper wire that is run to a ground rub bar located outside the powder booth just above the booth and positioned to make contact with the part hook. In a batch booth we would connect the copper wire to the booth wall and then to a smaller copper wire with a spring clip on it to connect to the load cart.





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[DCarr2]

damnit! I knew I forgot something when I poured my floor! I was going to pound a stake in the ground, and have them poor around it. FAIL

 

[happymachinist]

I specialize in multi color custom one offs, some with six or more colors. I rarely use my ground rod.

So you needed a ground rod at one point in time, what was your reason at the time? My gun is the Eastwood basic model, rudimentary, I know but I achieve good results with a little more work, I can't help but think a ground rod would help my setup.

Even if it doesn't help, I'm not out much, just the price of the rod and a little time.

Main reason I'd like to try it is on the forum I follow for powder coating, anyone having an issue getting their powder to stick, the first inquiry from the members on that forum are "How are you grounding your parts?"

My gun isn't as fancy as yours, no more than I coat I can't justify a real expensive unit. It's just a hobby but I really enjoy it. First coats don't give me any trouble, 2nd coats are so so, 3rd and beyond I have to hot flock, and I really don't like doing it.

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[Showkey]

As far as attraction of the powder, safety ( fire, arcing, shock) , controling waste ("overspray") and line coating and grounding.........Think their is a BIG difference in production line powder coating grounding and one off home coating as far as grounding.

Comparison is almost like a production down draft climate controlled paint booth to a home paint booth made from drop cloth and cardboard witha spray can.

 

[Coolerman]

I also have the Eastwood gun. I use the included ground wire with alligator clip from the control unit and have never had a problem with 1,2,3 or more coats of powder on a part. The key when multi-coating a part is to ensure you have an area on the part where you can get a good ground between coats. The very act of coating a part with multiple coats will cover up your grounding point! In between coats I will sometimes have to scrape off a bit of powder to get a good ground or use a hidden area on the part. On the very last coat, I powder up to the ground point, take the ground lead off then cover that area using no ground. Has worked for me many times.

This fall I will be setting up my powder coating system in my new shop. I have direct access inside to the 6ga wire that bonds my building to the outside ground rods (two rods, one driven 6' deep [solid rock was hit] the other a 8' rod buried 4' deep horizontally and the two bonded together). I will try using that ground for the parts to see if there is a difference. If there is, I will come back here and state the actual results.

 

[happymachinist]

As far as attraction of the powder, safety ( fire, arcing, shock) , controling waste ("overspray") and line coating and grounding.........Think their is a BIG difference in production line powder coating grounding and one off home coating as far as grounding.

Comparison is almost like a production down draft climate controlled paint booth to a home paint booth made from drop cloth and cardboard with a spray can.

I agree, my small ones-y twos-y jobs aren't going to benefit from the powder savings or powder loss to the floor, what I have experienced (I think) is some parts after sand blasting are full of static charge.

A couple parts with the static charge in my experience wouldn't even take a first coat no matter what I did. I covered them for the night and came back the next day and they coated like a dream...part of me thinks the part had some static build up that wouldn't let the powder adhere and it just took time to dissipate. I'm hoping the ground rod will aid in dissipating what I'm thinking is static a little faster....maybe cuda can weigh in on what she thinks?

I also have the Eastwood gun. I use the included ground wire with alligator clip from the control unit and have never had a problem with 1,2,3 or more coats of powder on a part. The key when multi-coating a part is to ensure you have an area on the part where you can get a good ground between coats. The very act of coating a part with multiple coats will cover up your grounding point! In between coats I will sometimes have to scrape off a bit of powder to get a good ground or use a hidden area on the part. On the very last coat, I powder up to the ground point, take the ground lead off then cover that area using no ground. Has worked for me many times.

This fall I will be setting up my powder coating system in my new shop. I have direct access inside to the 6ga wire that bonds my building to the outside ground rods (two rods, one driven 6' deep [solid rock was hit] the other a 8' rod buried 4' deep horizontally and the two bonded together). I will try using that ground for the parts to see if there is a difference. If there is, I will come back here and state the actual results.

I just picked up a ground rod and clamp for $26 and plan on posting my results also. We'll see how it goes...never coated in this location I'll try with and without the ground rod. Either way, it's a been good discussion and a nice little project.


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[sberry]

The ground may help with losses to the floor, I doubt there is such thing as 1 ohm to the earth connection. I wanted to copy and paste from the first link on this page but there sounds like some confusion by the author about what is really a fault return pathway.
I am always suspect of other recommendations when they are not completely clear and sure on this one basic point. He describes the earth for this, not correct and not clear at best.
All the babble from me here is only speculative fwiw but I suspect the opposite is true, its not for a return for the machine but to eliminate the potential for the floor to attract powder.

 

[Coolerman]

You will be lucky to get 50-60 ohms out of a typical ground rod. It takes special equipment to correctly measure this, so don't grab your multi-meter and expect to be able to!

This video by Mike Holt contains the best grounding information I have ever seen including a very detailed explanation of WHAT a ground is REALLY for. It's a must see video if you truly want to understand electrical system grounding.

 

[happymachinist]

The ground may help with losses to the floor, I doubt there is such thing as 1 ohm to the earth connection. I wanted to copy and paste from the first link on this page but there sounds like some confusion by the author about what is really a fault return pathway.
I am always suspect of other recommendations when they are not completely clear and sure on this one basic point. He describes the earth for this, not correct and not clear at best.
All the babble from me here is only speculative fwiw but I suspect the opposite is true, its not for a return for the machine but to eliminate the potential for the floor to attract powder.

So I did a little poking around with my volt meter on my powder coating unit. The ground prong on the unit that plugs into the wall, ohms out with the alligator clip also attached to the unit that is hooked to the parts or rack. (.9 ohms)

That being said, could using an extra earth ground allow for another path back to the unit via the extra ground rod?

Basically using the earth for another path or parallel circuit back to the source? Like in the video above when someone gets shocked it's a parallel circuit, you're getting shocked and 120VAC is going through your body but the rest of the circuit is also receiving 120VAC. In theory would it not all be connected back to the source?

I also probed a nearby outdoor outlet close to my newly installed ground rod. It read 26 ohms max...it fluctuated a bit but 26 ohms was the max. I know I don't have the fancy test equipment referenced above but thought I'd throw it out there to provide as much info as possible.

The the more I read I'm seeing that the extra ground might be for dissipating any static charge the parts might contain...like say lightning? Making the only charge to reach the parts the one coming from powder coating unit, helping better powder adhesion.

I appreciate your time, admittedly I was a little discouraged when you and wylie basically said poppycock!...but now I'm on a quest for knowledge and understanding. Weather it does work or it's all urban myth like you've said I'm trying to figure out why.



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[sberry]

The the more I read I'm seeing that the extra ground might be for dissipating any static charge the parts might contain...like say lightning? Making the only charge to reach the parts the one coming from powder coating unit, helping better powder adhesion.

I appreciate your time, admittedly I was a little discouraged when you and wylie basically said poppycock!...but now I'm on a quest for knowledge and understanding. Weather it does work or it's all urban myth like you've said I'm trying to figure out why.

This discussion is really good for working on a lot of the confusion about grounding. I didn't read Holt and probably should but have read others from some guru types. It takes a while for this thought process to become a reflex. When I started was all about wire size and voltage drop, as I age these have become less of an obsession while short circuit protection has become almost automatic and sized before anything else,,, as I said, reflex to some extent, same for rods and uffers and in some cases wire size and length for those.
Wylie isn't a fan of Westom who pops in here on occasion but I think he may be an engineer who works in lightening equipment etc, he has good take on it due to the fact this is all involved in "surge" protection.