Got Static?

[Ed Lang]

I think I need to run some ground wires.


Take a look at what happened last night in the shop.

http://kc4ylx.smugmug.com/gallery/1279086

Yes, it was loud and I just happened to be looking at the cyclone when the charge found ground!

I went to the house and got the camera took the shots and decided I had had about all the fun I could stand for one night..... Running ground wires tonight and back to the planer I go.

[Don Baer]

Your own little lightning storm...:eek:

[Jim Becker]

Just as an aside, the wire you run is technically a "drain"...you can't really ground plastic, per se. ;) It will be interesting to see how you are able to accomplish this at the cyclone...those will be big wraps!

[Don Baer]

Just as an aside, the wire you run is technically a "drain"...you can't really ground plastic, per se. ;) It will be interesting to see how you are able to accomplish this at the cyclone...those will be big wraps!

I'd be tempted to try to dangle a ground wire in the airstream in the cyclone. That might work.

It reminds me of when my dad used to work the high voltage power distribution system for the power company. He had a chain that was welded to the chasis of the truck. When the'd part the trunck underneath the power lines the'd drop the chain to ground the vehicle so they would get shocked when they got back into it.

[Bruce Volden]

Ed,


Good thing you don't have your shop in a grain elevator!!! When it discharges sumpin's gonna 'splode.
You can buy a roll of braided copper and use it to "ground", or install new metal ductwork??!! Bruce

[Ed Lang]

I have the wire, just never seem to get around to installing.

My plan is the sprial the wire around the duct work and the body of the cyclone.


Does anyone know for sure if I drill a hold and push a short length of wire into the air stream along the pipe if that will be better than just the outside spiral wrap?

[Jeff Horton]

OoooK, so what happened? Everyone keeps saying that PVC can't build up a static charge?? Does this official prove this false and it can? Or did Ed do something wrong??

Once I decide on how to rearrange my shop I am going to by a clearvue and installe it with PVC duct work too. Now I don't want to make that same mistake.... what ever it was.

[Don Baer]

I am suprised with a humidity of 57% he had that much static but I will install grounding when I build my new sustem in AZ where the humidity is sometime in the single digits

[Barry O'Mahony]

OoooK, so what happened? Everyone keeps saying that PVC can't build up a static charge?? ?? I've never heard anyone say that. PVC is an excellent insulator, and is thus very good at building up, and subsequently holding, a static charge.

[Barry O'Mahony]

Does anyone know for sure if I drill a hold and push a short length of wire into the air stream along the pipe if that will be better than just the outside spiral wrap?I don't think wrapping wire around the outside does much of anything. The inner surface will still build up a charge quite readily. The plastic is an excellent insulator, so the wire on the outside won't discharge a charge on the inside.

[Jim Becker]

Barry, I can't cite where, but I seem to recall reading awhile back that the drain on the outside was just about as effective as on the inside...without the clogging potential. But I could also be hallucinating. I have little experience with PVC duct work...I use metal.

[Kent Fitzgerald]

Everyone keeps saying that PVC can't build up a static charge??
I 've never heard anyone say that.

However, many have argued that static discharge form PVC pipe is very unlikely to cause a fire. Personally, I use metal duct becasue I've actually found it to be cheaper than 6" PVC, easier to work with, and it looks cooler too.

[Michael Adelong]

OoooK, so what happened? Everyone keeps saying that PVC can't build up a static charge?? Does this official prove this false and it can? Or did Ed do something wrong??

Once I decide on how to rearrange my shop I am going to by a clearvue and installe it with PVC duct work too. Now I don't want to make that same mistake.... what ever it was.

Jeff, The material that an object is made of has nothing at all to do with it's ability to build up a static charge. Any time 2 objects rub together, there is the potential for one of them to build up a charge. Environment plays a big part in it. Ever see those little fiberglass looking sticks hanging off of an airplane wing? They are there because the air moving past the skin of the airplane pulls the weakly bonded electrons away from the aluminum molecules of the airplane. Since there is no nearby source of free electrons (like the (a) ground), this actually does cause the aluminum to weaken. The little sticks "give up" electrons more easily than the aluminum, so they are put on the plane to be the sacrificial source of electrons. When a large, fast plane lands, you really don't want to touch it right away because there is a potential for a decent shock. You'll notice that the first ground crew person to touch an aircraft arriving at the gate does so with a large ground wire that plugs into a ground lug on the plane. That's a big part of the reason it seems that you sit there forever waiting for the doors to open. Sometimes the guy with the ground wire ain't so quick.

What you're missing here is this. Most of us have PVC tubing that eventually connects to a metal DC housing. The dust in my DC swirls around in a plastic bag that is wrapped around a grounded metal housing. As the dust swirls around, it has plenty of free electrons available from that same grounded metal housing to replace the ones that the wood rubbed off of the bag (not to mention that some of the dust actually does sit in the bottom of the bag, and the rubbed off "extra" electrons in the wood are available to the plastic again). The swirling dust cloud is in no danger of creating a large discharge like the one we see in the pictures. The PVC tubing in my shop does build up a little static, but only on the planer and jointer drops, and only after a long run. It is not a problem because there isn't enough suspended combustible material in a confined space for sufficient time to create the conditions necessary for an explosion or fire. That cyclone has plenty of wood flying around in it rubbing electrons off of the acrylic. The only source of free electrons I see is at the top, near the motor (which I assume (hope) is grounded). The dust is swirling around at the bottom. Plastic is a lousy conductor, so the replacement electrons are having a hard time getting down that far. When the dust with the "extra" electrons does finally settle, it is in that paper composite (I think - what are these made of?) can. It doesn't look like a good conductor, either.

The grounded wire dangling in the cyclone may do the trick, but I would try some copper screen (or wide strips of it) wrapped around the body of the cyclone. Hold it in place with strap clamps like the kind holding my plastic bag on my DC and ground it. This would provide a larger surface area for the ground, providing free electrons closer to where they are needed. At least the next arc would have a much shorter path to ground...

Michael

[Ed Lang]

A little update from tonights work in the shop.

I connected a bare copper stranded wire to the frame of the 20" planer and ran it around the 6" flex duct for about 5'. I then went over to the cyclone and used the same kind of wire and wound it around the cyclone body. I continued to wrap the wire around the 6" duct work entering the cyclone for about 4'. This wire is grounded. I then started the planer and ran it till I filled the 55 gallon drum with shavings. I dumped it and then refilled it about half way before finishing up. The cyclone ran the entire time. I listened and watched for more light shows but didn't see or hear any. This temporary fix got me going tonight. Later I will wrap the outside of the entire system of 6" S&D pipe and tie it to ground. I had plaques for the Cub Scouts that I had to get finished tonight so my Cyclone upgrade has to wait.

You can bet I will have the system well grounded before I bring the 24" wide belt sander online! That thing will make much finer dust than I want mini lightning bolts going thru.

Metal duct was more expensive so I went with S&D 6". I am still glad I did, and would make the same decision again if I had to do it all over again. I think the S&D pipe is easy to install.

Everybody take care and I'll retreat back to the shop for a while now.

[Dale Thompson]

I think I need to run some ground wires.


Take a look at what happened last night in the shop.

http://kc4ylx.smugmug.com/gallery/1279086

Yes, it was loud and I just happened to be looking at the cyclone when the charge found ground!

I went to the house and got the camera took the shots and decided I had had about all the fun I could stand for one night..... Running ground wires tonight and back to the planer I go.

Ed,
We have had many posts about the potential for "explosions" in home shop dust collection systems. The overwhelming conclusion is that there is none! :)

There is no question that dust moving though ANY pipe system will have the potential for building up "static" electricity. It looks as though you developed an interesting scenario for building up a rather large voltage differential in your cyclone. The fact is that "voltage differential" is not going to be an "explosion" problem. Voltage differential, in and of itself, is not going to hurt ANYTHING because there is no "energy" involved. :) You need AMPS for destructive energy. To be ridiculous, the human body can take a jillion volts without harm. On the other hand, 1/4 of an amp through the heart can be fatal. :eek: It would appear as though your "voltage differential" just dissipated itself over the surface of your cyclone. Your 56% Humidity indicates that you had enough moisure in the air to allow this to happen. :confused:

As a suggestion, you will be wasting your time and wire by trying to "ground" a plastic pipe. Grounding it either internally or externally is equally futile. It just, "ain't gonna make no difference". Plastic is an insulator and insulators just DON'T conduct electricity - even to a grounding wire.

Don't get me wrong, plastic pipe or hose CAN build up static electricity. I've been "statically bitten" by my shop vac hose enough times to agree to that. The difference, again, is "voltage" vs "energy". ;)

If I had experienced your situation, the first thing that I would check would be my ground on the blower motor or any other obvious electrical connections. Assuming them to be OK, I would pride myself in the fact that I had created my own "weather". The only time I have heard of that before is in the building where the Space Shuttles are housed. I've heard that it is SO large that they can create their own weather conditions, including lightning! :cool: :D

Dale T.

[Ted Jay]

Ed,
We have had many posts about the potential for "explosions" in home shop dust collection systems. The overwhelming conclusion is that there is none! :)

There is no question that dust moving though ANY pipe system will have the potential for building up "static" electricity. It looks as though you developed an interesting scenario for building up a rather large voltage differential in your cyclone. The fact is that "voltage differential" is not going to be an "explosion" problem. Voltage differential, in and of itself, is not going to hurt ANYTHING because there is no "energy" involved. :) You need AMPS for destructive energy. To be ridiculous, the human body can take a jillion volts without harm. On the other hand, 1/4 of an amp through the heart can be fatal. :eek: It would appear as though your "voltage differential" just dissipated itself over the surface of your cyclone. Your 56% Humidity indicates that you had enough moisure in the air to allow this to happen. :confused:

As a suggestion, you will be wasting your time and wire by trying to "ground" a plastic pipe. Grounding it either internally or externally is equally futile. It just, "ain't gonna make no difference". Plastic is an insulator and insulators just DON'T conduct electricity - even to a grounding wire.

Don't get me wrong, plastic pipe or hose CAN build up static electricity. I've been "statically bitten" by my shop vac hose enough times to agree to that. The difference, again, is "voltage" vs "energy". ;)

If I had experienced your situation, the first thing that I would check would be my ground on the blower motor or any other obvious electrical connections. Assuming them to be OK, I would pride myself in the fact that I had created my own "weather". The only time I have heard of that before is in the building where the Space Shuttles are housed. I've heard that it is SO large that they can create their own weather conditions, including lightning! :cool: :D

Dale T.

This subject came up a while back on the Woodweb site in 2001 here:
http://www.woodweb.com/knowledge_base/PVC_piping.html

Ted

[Barry O'Mahony]

Barry, I can't cite where, but I seem to recall reading awhile back that the drain on the outside was just about as effective as on the inside...without the clogging potential. But I could also be hallucinating. I have little experience with PVC duct work...I use metal.Jim,

If it was the guy who wrote the FWW article, he recommends the drain wire on the outside, with the proviso they are connected to sheet metal screws, screwed into the pipe.

With this setup, there is no wire inside to induce clogging. The pointed ends of the screws develop a high voltage gradient, so any static charge is more likely to "arc over" and discharge through the screw and attached drain wire.

I get zapped from isolated metal objects in the duct path, like blast gates. I run a drain wire to keep them from getting charged. I don't think being "jumpy" and worrying about getting shocked is a good thing when working around powerful cutting tools.

[Jeff Horton]

Just for clarity, I have read a good bit on another forum that there was no reason to add ground wires with PVC ducting. Was not talking about this fourm.

[Ed Lang]

Barry - I like the idea of the screws. They will be easy to install and they do exactly what I asked about in my first post about drilling a hole and sticking a wire inside. Thanks!!

I know for a fact that putting a wire around the cyclone did stop the static from building up. Yes, I did it and touched the cyclone and pipe after running 6' of oak past the planer. I had run the same 6' oak pass the planer BEFORE adding the wire and I got a small static discharge to me. I also found that using a clamp to connect a 10' or so wire to the planer and placing the wire on the outside of the 6" flex hose did STOP the static on the planers end of the system.

Bottom line is, I am goind to run the drain wire along the 6" pipe and put sheet metal screws into the pipe every 4' or so. I am going to ground the drain wire on the cyclones end.

If I can create any more lightning in the shop, I'll let you know.

[Lee Schierer]

The charge is not like regular electricity, so removing the charge from the outside will also remove it from the inside. The fact that is plastic and plastic is normally an insulator has very little to do with it. Wrapping the wire around the outside should be sufficient. To keep the wire in place get some of the metal foil tape used to seal up duct work. I successfully grounded my entire pvc duct sytem simply by wrapping the excess power cord for my dust collector around the pipe 3-4 times.

[Ed Lang]

Lee,

Are you saying that you did not wrap wire around the entire length of the pvc pipe run and got good results? If so, then I don't need to wrap all of my pipe.

If I am going to use the foil tape to keep the wire in place, why not just run the foil tape the length of the pipe? Just wipe and stick. Sounds too easy but I think I just might try it.

Thanks and I'll report back how whatever I do, did.

Right now I am in the throws of buying a 24" wide belt sander so my mind is elsewhere.

[Lee Schierer]

Lee,

Are you saying that you did not wrap wire around the entire length of the pvc pipe run and got good results? If so, then I don't need to wrap all of my pipe.

If I am going to use the foil tape to keep the wire in place, why not just run the foil tape the length of the pipe? Just wipe and stick. Sounds too easy but I think I just might try it.

Thanks and I'll report back how whatever I do, did.

Right now I am in the throws of buying a 24" wide belt sander so my mind is elsewhere.
Yes, I wrapped the cord around one part of my system just to get the cord up off the floor and the staic went away on the rest of the system, though it was never all that bad to begin with. Running the wire and tape or just the tape since it is aluminum and will conduct should work just fine. You need to give the charge a place to go and a wire or tap to ground should do that.

The rubbing of wood chips and saw dust on the plastic is what is creating your static and in a dry environment, the charge can build up. Ever see one of those vandegraff generators in school with the aluminum ball on top and a rubber belt running inside a plastic tube?? Well your DC with chips is doing exactly the same thing. Give the elctrons a conduction path to ground and the charge will never get created.

[Darl Bundren]

I am working on installing my Clearvue and pvc ducting and have pored over sections of Bill Pentz's site. He mentions a method of grounding pvc that looks pretty easy that folks might want to consider: http://billpentz.com/woodworking/cyclone/Ducting.cfm#StaticElectricity

Scroll down a bit and click on the "Static Electricity" link if it doesn't take you right to it.

[Barry O'Mahony]

The charge is not like regular electricity,Can you explain what you mean by that?

so removing the charge from the outside will also remove it from the inside. The fact that is plastic and plastic is normally an insulator has very little to do with it. Wrapping the wire around the outside should be sufficient.how does this work? What is the mechanism by which removing the charge from the ouside will also remove it from inside? This Physics major doesn't understand.


To keep the wire in place get some of the metal foil tape used to seal up duct work.Perhaps the interior is discharged by arcing through the seams in your pipe to the foil tape (?).

I successfully grounded my entire pvc duct sytem simply by wrapping the excess power cord for my dust collector around the pipe 3-4 times.When you say "successfully", how did you measure that; i.e., what differences were observed after you did this, as compared to how things were before you did this?

[Dale Thompson]

This subject came up a while back on the Woodweb site in 2001. Ted

Hi Ted,
Several months ago, I SWORE that I would NEVER again respond to a question on grounding home shop dust collectors. So much for my self control. ;)

Anyway, since I see that you have only posted on the THE CREEK three times, I thought that I would break my vow with the main emphasis on welcoming you to SMC. We have a LOT of fun here (except for this ding-blasted, no pun intended, DC explosion phobia) and I hope we will see more posts from you. :)

Anyway, in one of our previous threads, a link was posted to some high-tech work done by, as I recall, some Physicist from a major university. The conclusion of his study was that there was NOT a problem!!

Personally, I have been in the fire protection engineering business for about forty years. Over the years, I have known a number of engineers who have worked in the area of "Explosion Suppression". Most of that work is done by one company located in the Boston area. Their biggest problem is NOT suppressing an explosion but creating one in the first place. A dust explosion REQUIRES that ALL three conditions necesssary for a fire (An explosion is nothing more than a rapidly moving fire) are present and, most importantly, present in the VERY SPECIFIC quantities required for a fire. The fact is that two of these, the oxygen and the dust particles (their size is ALSO a variable) MAY occur but that will happen with about the same probability as I have of winning the $300,000,000 lottery twice in a row. ;)

The other element required is a high energy heat source. Static voltage, in and of itself, is neither high energy nor is it a credible heat source.

Explosions in industrial dust applications and grain handling (elevators) applications are ALMOST always, if REALLY investigated, traced to OPEN flames resulting from an overheated motor or a burning conveyor bearing. :( By ALMOST, I mean 90+%. The rest are probably the result of a stray piece of metal (most alloys of aluminum are the worst) colliding violently with another metallic object. :(

As far as the National Fire Protection Association is concerned, I have been on several NFPA Standards Committees. Unfortunately, NFPA Standards are NOT pure "technical" standards. They are "concensus" standards! This means that they are a COMPROMISE between technology, economics and, unfortunately, politics! :eek: My opinion of NFPA Standards? They are better than NOTHING but sometimes it is a "photo-finish". ;)

SO!? Go ahead, folks, make your collection system resemble a spider web with all of the wires that it takes to make you feel safe. My suggestion would be to let the spiders do it FOR you! It's a lot cheaper and the result will be the same! :)

Whatever, my bedtime prayer for tonight will be that GOD strikes me DEAD if I EVER respond to another "DC EXPLOSION" thread!!

With that said, Ted, I repeat my, "WELCOME TO THE CREEK" comment. :) We can only hope that some reckless "outsider" will not bring his DC close to the water when we are dangling our feet in the water of said CREEK! The "static" discharge could be devastating!? I am already brain damaged enough to be resistant to such "dangerous" behavior but I would hate to see the same thing happen to YOU!! :)

Dale T.

[Ed Lang]

I posted the link to the pictures not to start a fire on the banks of the creek but to show what happened to my system. If it didn't blow up then, I don't think it will ever blow up. I did find that running a wire did stop me from getting shocked. I dont' like getting shocked! I also have two computers, one laser engraver and one CNC Router in the shop, all running electronic controls. Electronic controls do not like static electricity. Good grounds to make sure there are no differences in potential is a good thing. I will do what I need to to stop the static for the electronics and my jumping when I get shocked.

I don't need a leyden jar to tell me if I have static or not, the hair on my arms is doing a fine job.

[Dale Thompson]

I posted the link to the pictures not to start a fire on the banks of the creek but to show what happened to my system. If it didn't blow up then, I don't think it will ever blow up. I did find that running a wire did stop me from getting shocked. I dont' like getting shocked! I also have two computers, one laser engraver and one CNC Router in the shop, all running electronic controls. Electronic controls do not like static electricity. Good grounds to make sure there are no differences in potential is a good thing. I will do what I need to to stop the static for the electronics and my jumping when I get shocked.

I don't need a leyden jar to tell me if I have static or not, the hair on my arms is doing a fine job.

Ed,
10-4 on the static shock! :eek: I have kicked my shop vac more than once in retribution. :mad: All I ever got from that was a sore foot and ten-fold retribution from the shop vac! :(

A BIG 10-4 on keeping static electricity away from your electronics!! :) In that situation, a "discharge" can be WORSE than a fire in that it can affect more than one machine! :(

Anyway, Ed, don't worry about starting a fire on the banks of THE CREEK! :D The many mean, deletion-crazed, power-mongering and over-paid Moderators on THE CREEK have no problem with using my ever-thinning blood to extinguish any such situations! :cool: ;) :)

Lastly, your pictures were GREAT!! Thank you for taking the time to take and post them. :) I've already copied them to a file for future use.

Dale T.

[Tom Andersen]

The charge is not like regular electricity, so removing the charge from the outside will also remove it from the inside. The fact that is plastic and plastic is normally an insulator has very little to do with it. Wrapping the wire around the outside should be sufficient. To keep the wire in place get some of the metal foil tape used to seal up duct work. I successfully grounded my entire pvc duct sytem simply by wrapping the excess power cord for my dust collector around the pipe 3-4 times.

I am an engineer and have designed a lot of electronics through the years. With all due respect, I have a hard time believing that wrapping a wire around the outside of a plastic duct will remove an electrical charge from the inside of the duct!

[Ted Jay]

With that said, Ted, I repeat my, "WELCOME TO THE CREEK" comment. :) We can only hope that some reckless "outsider" will not bring his DC close to the water when we are dangling our feet in the water of said CREEK! The "static" discharge could be devastating!? I am already brain damaged enough to be resistant to such "dangerous" behavior but I would hate to see the same thing happen to YOU!! :)

Dale T.

Thank You for the Welcome...

As you will notice in my post, I didn't offer my opinion on the matter. It's almost like asking who makes the best table saw.:D
This is some of my experience with Static Electricity... When I'm at work (computer aided design, intergraph PDS, for the petrochemical industry), I'll on occasion will be engaged in conversation with one of my fellow employees and point to something on his screen, touch it, and get shocked. Nothing major... but it is annoying. I should know better by now, but I still do it on occasion, but for the most part I just let it pass and keep on going...:p

[Ed Lang]

My final thoughts on this are as follows.
I used bare copper wire from Radio Shack that they sell for antenna wire, because I had it. I started where the 6" pipe goes into the cyclone and installed a sheet metal screw with the wire around it. I wraped the wire around the outside of the pipe and did not worry about how many wraps per foot I did, but just made it look nice. When I got to a point I wanted to anchor the wire I installed another screw and made a turn around the screw. This method seems to hold the wire just fine. After installing wire on my trunk lines, I started on the 6" drops to the equipment. I connected my wire to the trunk line wire and continued down to the equipment. When I got to the 6" flex line I installed a screw and then continued to wrap the flex pipe. I make a quick disconnect at each machine so I stopped the wire with a screw before I crossed over the quick disconnect. I did not cross over any quick disconnects. Now I can disconnect any line and the flex will still have wire on it. Machines are gounded via the power cable.

To test the results, I started the 20" planer again and ran several oak boards thru it. I did not get any shocks or static cling when I moved around the 6" duct. I can now touch it and not get shocked. So far so good. While I am running the planer, my wife is watching the cyclone and does notice some sparks on the cyclone body. I shut down the planer and cyclone and then wrap wire around the cyclone body and connect it to the trunk line wire. I use screws into the cyclone body to secure the wire in a few places. I did notice static on the cyclone body while installing the wire. It was exactly like putting you hand on the TV screen and noticing the static discharge noise. After finishing up the cyclone body I continued to route the wire over to the filter stack and attached the end there.

Now I start up the planer and cyclone, with my wife watching, and plane a lot more oak than I had in any other tests I ran. No static on the 6" flex, duct or cyclone body. No shocks. I turned off everything and ran my hand over everyplace I had gotten a shock befoer..... None.

So, for "me" the short time I spent installing the wire, was worth it. I am happy that I dont' get shocked and there are no more little storms in my cyclone. I did this to prevent me from getting the shock.

I don't need to know exactly how or why it worked for me, just that it did. I wrote all of this here so maybe someone else who is getting shocked could use this information to help them.

I am happy to take pictures if you like, just let me know.

Now back to woodworking where my only shocks will be when something fits tight the first try!

[Rob Beckers]

I am an engineer and have designed a lot of electronics through the years. With all due respect, I have a hard time believing that wrapping a wire around the outside of a plastic duct will remove an electrical charge from the inside of the duct!

It doesn't. What it does is put the outside at ground potential (for the most part), so touching it doesn't result in sparks and fireworks. The inside is likely still charged as before (though with the ground wire nearby it may bleed off charge a little easier through anything that conducts, even if it's a bad conductor).

Rob
-/-
(A fellow Electrical Engineer)

[Curt Harms]

Jeff, The material that an object is made of has nothing at all to do with it's ability to build up a static charge. Any time 2 objects rub together, there is the potential for one of them to build up a charge. Environment plays a big part in it. Ever see those little fiberglass looking sticks hanging off of an airplane wing? They are there because the air moving past the skin of the airplane pulls the weakly bonded electrons away from the aluminum molecules of the airplane.

Michael

I can't speak to large transports, but I've gotten out of a LOT of ungrounded smaller jet aircraft and NEVER had a static discharge. The static wicks(proper name) are on the trailing small radius surfaces to bleed off P-static (precipitation static). A charge may accumulate when flying thru precip, especially snow. I remember a few nights watching St. Elmo's fire play across the windshield. Looks pretty cool, sorta like those glass ball affairs with "lightning" in them. What ain't cool is the same P-static can cause VHF nav radios to lose their signal, and cause continuous static on VHF Com radios, except when receiving or transmitting. This may have been due to corrosion between mating surfaces on the airframe and static wick, I'm not sure.

If some bozo paints control surfaces with with static wicks removed then installs the static wicks WITHOUT removing the paint, that WILL cause problems, that I know.

[Cameron Reddy]

It doesn't. What it does is put the outside at ground potential (for the most part), so touching it doesn't result in sparks and fireworks. The inside is likely still charged as before (though with the ground wire nearby it may bleed off charge a little easier through anything that conducts, even if it's a bad conductor).

Rob
-/-
(A fellow Electrical Engineer)

Here is my uneducated analysis (guess). The plastic does, in fact, allow some electrical charge to bleed through. I have an electric toothbrush that charges through its plastic housing. I believe the audio industry uses "conductive" plastic... Now, what in the heck that plastic is made of is completely unknown to me. I also note that electricians' screwdrivers have a different plastic insulation (and a lot more of it) than other plastic-handled screwdrivers through which you can presumably get a nasty shock...

[Bob Myers]

Ed, somewhere on Bill Pentz's site is a link to an approach that describes grounding pvc using foil tape on the interior of the pipe. Claims that it solved the problem of static buildup.
-Bob Myers


I think I need to run some ground wires.


Take a look at what happened last night in the shop.

http://kc4ylx.smugmug.com/gallery/1279086

Yes, it was loud and I just happened to be looking at the cyclone when the charge found ground!

I went to the house and got the camera took the shots and decided I had had about all the fun I could stand for one night..... Running ground wires tonight and back to the planer I go.