Grounding dust collector tube

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Friction is the main cause of static electricity and in the dust extraction system is where it builds up and can cause a spark. This is not as common in metal piping as the plastic piping. With the metal piping it's usually grounded at the machine or it's touching other metal in the shop that grounded. Not the case with plastic pipe and that's why you will see a grounding wire in some kits you buy. It's like when you walk across carpet and you touch a metal screw on a light switch or other metal in dry climates. I am sure most of us has seen a spark from a finger when we touch something. Well at least I have. In the case of dust extraction and a spark like this can be a dangerous situation. You should see how much grounding is in a grain elevator. It's huge.
Lin.
 
WriteON said:
Please explain grounding. I read somewhere about grounding the tube. Where and why? Thanks.
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If you are talking about grounding a dust collectors pipes system then you will get as many answers as you do when asking about applying CA. Two trains of thought about this. Basically the theory is that especially if you use plastic pipe for your duct system and run long lengths that as your dust collector runs, the moving air is dry and static can build on the inside of the pipe and some sort of discharge such as a piece of metal flying through it can cause a discharge and create a spark thus setting the fine dust on fire. This occurs alot in silos that store various products like corn flower and this of this nature and thus they are well grounded and is code. Now with that said it would take a long time for this static to build in a 4" to 6" dust collector system and you have more than fine dust running through it AKA chips of wood. But many people like to be on the safe side because a home or shop is a place where there is constant dust problems.

Again 2 theorys on how to ground a PVC pipe system. One is run a bare copper wire inside through the pipe and attach at blast gates. Now the problem that comes into play here material can become entangled around the wire if not layed taut and left to curl inside. Then the pipe can become clogged. This is so true with wht we do. Those curly strings that we get comming off the acrylic pens we turn would be a hugeeeeeee problem. Heck I have had to clean my hose out because they stick to the sides because of static cling and I do not have a wire running through my system. The other method and one that is followed more often is to wrap a bare copper wire around the outside of the pipe and attached at blast gates and different locations along the pipe. All these methods need to eventually wide up attached to a grounded source such as a water pipe just like your service is. No need for ground rods. Now if you have a metal pipe system as I do, then simply attach a ground wire to the grounded system of your home. The short flexible hoses that you have running to the tools need not be grounded because they are when the ose is attached to the tool some how. Unless all plastic parts are used such as plastic blast gates and plastic hose connectors. But the run is so short it will not cause a problem. Now you may notice dust collecting on the outside of hose which is an indicator that static cling is present and then you may want to run that wire inside or out and attach to system.

Now this theory has been debated among woodworkers for many years and I have never read anyone having an explosion from dust running through their dust collector systems. But as most have said an ounce of prevention can save lives. So do you feel lucky?? Well Punk do you?? :) These are my thoughts on the subject.
 
jttheclockman said:
So do you feel lucky?? Well Punk do you?? :) These are my thoughts on the subject.
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Do I feel lucky? Luckiest man in the world. I'm using 4" transparent flex hose.
 

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WriteON said:
Do feel lucky? Luckiest man in the world. I'm using 4" transparent flex hose.
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You do realize that was my Clint Eastwood impression right?? Another attempt at hummor which I think I need to stop because this site is way to serious.

If that is your setup for dust collecting you have no worries. Too short for a problem.
 
jttheclockman said:
You do realize that was my Clint Eastwood impression right?? Another attempt at hummor which I think I need to stop because this site is way to serious.

If that is your setup for dust collecting you have no worries. Too short for a problem.
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Your humor is right on. And I'll tell you There is nothing like a good piece of hickory. My feelings on taking things too serious is.....life is too serious to take seriously. Keep on being yourself JT. I'm not changing.
 
WriteON said:
Your humor is right on. And I'll tell you There is nothing like a good piece of hickory
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I was watching The Big Bang Theory rerun the other night and I think it was Leonard who used that line so it stuck in my head from a flashback. I screwed it up anyway because the line is Do you feel lucky?? Well do you, Punk?? :)
 
Further to what John aka Dirty Harry said.

A home dust collector system can't generate a big enough spark to causes a fire and we can't generate enough dust in the pipe for an explosion. I found a site the other day (didn't bookmark it though) that said to get a coal dust explosion there has to be enough dust in air that you can't see a 25 watt light bulb 6' away. I can't think of any machine in a home shop that can create that much dust in a duct.

The two reasons for trying to dissipate/ ground a duct is the spark stings and can be distracting when using a machine. So safety. The second is a more recent reason. Computers in CNC machines can be fried by a static discharge so if you want to protect a piece of electronics go with metal ducting.

Here is a little reading for you.
 
Curly said:
... there has to be enough dust in air that you can't see a 25 watt light bulb 6' away. ...
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That happened to me once while rip cutting thick, somewhat wet wood on a radial arm saw, decades ago, before dust collection was common in home shops. There was a lot of burning in the cut, and the garage filled with sawdust. It was so thick I could not see "a 25 watt light bulb from 6 feet away."

I had to get out of there, so I opened the door and went into the house. To my stunned surprise, the house was full of sawdust, too. I could not figure out how the sawdust got through the door.

... until I took off my glasses.
 
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