# Static Electricity



## lalkie (Sep 19, 2015)

I have a Dewalt DW734 planer. When I run boards thru it and touch the metal out feed table I get a mild shocks of static electricity. I generally have it hooked to a dust collector. Is there a cure for this. It is just aggravating and possibly a safety hazard as it could ignite the dust. Anyone experience this or have a solution to? Thanks Larry


----------



## jacksdvds (Jun 13, 2015)

Ground the machine, add some moisture to your shop, DON'T TOUCH THE METAL, ground yourself before you touch anything. In late spring to late fall here in Arizona it is constant static shocks every time you touch metal. The shock is probably you and not the machine.


----------



## MrRon (Jul 9, 2009)

I wouldn't worry about igniting sawdust. Dust has to be super fine, like flour to ignite. Sawdust just isn't fine enough.


----------



## papadan (Mar 6, 2009)

Ground your DC system like the manufacturer said to!


----------



## alittleoff (Nov 27, 2014)

Even if it grounded its going to happen no matter what you do. It's you not the machine. I usually slap my hand to metal before I touch it, if I think to.


----------



## Lenny (Sep 28, 2008)

Larry, I don't know if there is a "cure" for it but I know it is quite common and happens to just about all of us. My planer is in close proximity to my table saw (TS). I often place a hand on the TS before reaching to retrieve the board from the planer, thereby grounding myself. As *MrRon* states, you need not be concerned about sawdust igniting. From what I have read, there is no recorded instance of sawdust ignition/explosion. Some go as far as to say it is a myth. If interested, do a Google search on the topic and you'll see what I mean.


----------



## papadan (Mar 6, 2009)

You guys are ignorant, static shock is completely preventable. Your saws and planers don't shock you because they are grounded. The moving air over the plastic pipes or tubes of the DC causes static. A shop vac will cause it too. Ground the ductwork for your DC and you wont get any static shocks. That's the Cure, Lenny.


----------



## jonah (May 15, 2009)

You can also ground your planer tables directly if for some reason they aren't electrically connected to the ductwork. A very small wire is all you need.


----------



## SanderBash (May 31, 2017)

As some have suggested, the static probably comes from your dust collection (many dust particles travelling at high speeds can cause static buildup, especially in dry conditions). Try planing a few boards with the dust collection off to check if it is indeed the culprit.

Also try wearing other shoes. In a particular university building I (and others) have found out that wearing shoes with a specific rubber sole causes static shocks everytime you touch a metal door jamb, handle or window frame.

While annoying, it should not be a safety hazard.


----------



## Lenny (Sep 28, 2008)

Ignorance implies lack of knowledge. I have plenty of that *papadan*. The problem is navigating all of the info available. Many "experts" say it's a waste of time to "ground" pvc ductwork. Others say it's worth the time, just in case. Some say a copper wire inside the ductwork is sufficient, others, you should run it both inside and out. Most of these articles are addressing the explosion issue more so than the static electricity one. Again Larry, what I've read indicates the likelihood of an explosion is practically nil. But I think we all agree grounding is worthwhile regarding static electricity.

While I am not ignorant, I will admit to being an idiot at times. My DC system IS grounded with 18 gauge copper wire running from the DC, through the ductwork and terminates at each tool. Well, almost each tool. This discussion made me realize I never added the ground to my new-ish planer! No wonder I am getting shocks. DUH!


----------



## papadan (Mar 6, 2009)

Lenny, I have to say that the "experts" (I have read their reports too) are also ignorant. They base their opinion on their own experiences. ALL manufacturers of DC equipment say to ground the system. There are plenty of commercial systems that have blown up because of static or an electrical short. They say there are no reports of home systems ever having a problem, I say there are some that just didn't know what caused the explosion or fire. Remember, the internet is not that old and there are still lots of people that don't use it. I started in the late 80s with computers, but I still don't have or want a "smart" phone. I have never sent a text to anyone. To communicate with someone, I call them or knock on their door. Anyone can prove the existence of static, just use a shop vac for a few minutes without touching anything, then touch one of your machines with the vac running, do this in the dark and you can see the spark between you and the machine. And that is just a small shop vac, not a big DC system.


----------



## scr5008 (Sep 12, 2015)

I haven't tried this yet, but a guy at work says he ran a bare copper wire INSIDE his shop vac hose, fastened to the hose at the user end (so it doesn't get sucked through), then ran a small rivet through the other shop-vac end to extended the wire externally and ground it to the machine he was running.

The corrugated plastic hoses of shopvacs also stir up a lot of air, and little particles in air create the static, when you touch it, zap. If you give the static a chance to ground, it won't hit you.


----------



## papadan (Mar 6, 2009)

The guy at work is correct!


----------



## papadan (Mar 6, 2009)

I apologize if my posts in this thread seam short or mean. This subject has been covered hundreds of times and argued by the best. There is only one true answer. Ground your DC system like the manufacturer suggests and you will prevent static shocks and avoid any possibility of static explosion.


----------



## ScottM (Jul 10, 2012)

I just use a Dust Deputy and it came with a grounding wire for just this reason…


----------



## pintodeluxe (Sep 12, 2010)

I had this issue on my 735. It was related to a large volume of air moving through flex hose. I grounded the spiral wire to my metal DC duct work and it completely solved the problem. If you don't have a convenient way to ground the hose / pipe you might try anti-static flex hose.



















The shorter the length of flex hose, the better - both in terms of static shock generation and general dust collector performance.

Good luck with it.


----------



## ArtMann (Mar 1, 2016)

papadan,

I don't mean to be rude but you haven't supplied any more proof than anyone else. All you are supplying is talk. Where are your references?


----------



## wormil (Nov 19, 2011)

It is my personal belief that grounding hobbyist level equipment is a waste of time. It is not my area of expertise, I have no original research, so all I can do is evaluate arguments made, the education and qualifications of the people making them, check any sources cited, and having done that for years: I am overwhelmingly convinced that grounding hobbyist level equipment is unnecessary. Moreso I am unconvinced it is even possible to ground a plastic pipe. If anyone wants to change my mind, you'll need something compelling and verifiable. And if you don't care what I think, that's okay too because I'm only responsible for my own dust collection.


----------



## DS (Oct 10, 2011)

Ok, all the above comments and suggestions are great. Grounding the tools, wire inside the dust collector hose, etc.

HOWEVER, just having a grounded tool does NOT prevent ESD (Electro-Static Discharge). It merely gives the charge a pathway to go to ground. You will still get zapped if you collect a charge on your person and then touch a grounded object.

Here is a neat trick: Dilute your favorite fabric softener with water half-and-half in a spray bottle then mist the areas where static is accumulating. This lowers the surface tension and prevents free electrons from jumping off those surfaces and pooling up in places you don't want them..

You can spray inside the dust collector hose, your clothes and the floor around the tools. (Just be careful not to create a 'slick' area that you might slip on.)

In a former life, I worked in the Aerospace Industry in a Zero-ESD rated high-bay. They take that rating very seriously; Special floors, conductive footwear and bunny suits.

This works! In the summer I usually mist the carpets inside the house too.

And now you know.


----------



## lalkie (Sep 19, 2015)

Thanks for the response guys. I will probably run some kind of ground with the wire that is in the clear hose. It is probably more of an aggravation than a danger. Thanks again I appreciate the information I get on this forum. Larry


----------



## papadan (Mar 6, 2009)

Read the owners manual that comes with any DC on the market, even HF!


> papadan,
> 
> I don t mean to be rude but you haven t supplied any more proof than anyone else. All you are supplying is talk. Where are your references?
> 
> - ArtMann


----------



## wormil (Nov 19, 2011)

> Read the owners manual that comes with any DC on the market, even HF!
> - papadan


The manual to my Delta DC only mentions using a grounded outlet, nothing about grounding ductwork. Mine is an older model so I checked the manual on a current model and didn't see anything there either.


----------



## AlaskaGuy (Jan 29, 2012)

You would think an electrical engineer would jump in here and straighten this all out. I'm pretty sure we have on on this board.


----------



## oldnovice (Mar 7, 2009)

I bought a WEN 4 inch anti static hose from Home Depot: which is less than 1/2 the price of the one from "Rockler": http://www.rockler.com/rockler-dust-right-4-in-anti-static-dust-hose.

I only used about 5 feet of the hose and it works as advertised *for less money*!


----------



## 280305 (Sep 28, 2008)

So much of the advice in an owner's manual is written for the sake of the legal department that a valid recommendation is hard to spot.


----------



## AlaskaGuy (Jan 29, 2012)

For what ever it may be worth.

http://www.woodcentral.com/articles/shop/articles_221.shtml


----------



## ArtMann (Mar 1, 2016)

> You would think an electrical engineer would jump in here and straighten this all out. I m pretty sure we have on on this board.
> 
> - AlaskaGuy


I am an electrical engineer but I don't claim to have any facts that I can't prove. Of course, there are many reports of dust explosions, most of which are from grain storage facilities. I read several reports last night. I could not find any report of a dust explosion that bears any resemblance to dust collectors in a home woodshop. One report I read alleged that some kind of woodworking factory exploded because of a lack of dust collection. It was due to piles of loose very fine sawdust collecting in the rafters and on top of big machinery. I know for a fact that it takes a certain concentration of fine dust to sustain an explosion and that level is thick enough that you can't see through it even over a few inches. This is not proof but it is pretty solid evidence. There is one other thing that causes me to doubt that dust collector explosions are likely. I have been on several woodworking forums, some of which for a decade. I must have read posts from tens of thousands of different people. I occasionally read someone claim that he is aware of a dust collector explosion but when you press them, they can't name names or places that can be verified. The fact is I have yet to hear of a single instance of a verifiable dust collector explosion. Even if there were one, it would be noteworthy because of its rarity - kind of like the fear of commercial airline crashes.


----------



## wormil (Nov 19, 2011)

In the end facts won't matter because tomorrow or next week all the people who believe you can ground PVC or air or your DC will explode are going to keep arguing.


----------



## oldnovice (Mar 7, 2009)

When I lived in Illinois a colleague and I would take our glue ups here for sanding on their wide belt sander.
This happened once before after I moved to California!










The link is to the web article about *Walnut Hollow in Dodgeville Wisconsin!*


----------



## ArtMann (Mar 1, 2016)

So, was the damage here caused by their dust collection system or was it caused by the lack of one or something else? The link you provided didn't say.


----------



## wormil (Nov 19, 2011)

I would think the danger is where small particles are suspended, the upper bag or filter. But even there they are pushed against the filter medium. I can't imagine how an explosion would occur inside ductwork. The particle count will never be high enough.


----------



## oldnovice (Mar 7, 2009)

*ArtMann*, as far as I can remember the cause was never made public.

When I lived and worked in Illinois, the company I worked for manufactured all types switches including explosion proof.
In order to be explosion proof the switches must have Factory Mutual (FM) approval which are some of the toughest commercial/industrial standards.
There are a number standards agencies that govern approvals for that specific industry; food/beverage, oils/gas, transportation, ordinance, marine, consumer.
You have probably seen the trademarks for many of these domestic agencies and possibly for a lot of the international agencies without realizing what these mean.


----------



## DS (Oct 10, 2011)

Oakcraft Cabinets in Phoenix had a dust collector fire/explosion at their facility four or five years ago.
It was devastating. Fortunately they recovered and are moving forward.

The idea behind the wire inside the dust collection pipe is that charged dust particles inside the pipe will bump into the wire and dissipate the charge to ground before they can develop a high enough voltage to spark a fire.

You aren't "grounding a plastic pipe" as was previously suggested.


----------



## DS (Oct 10, 2011)

Do not try this at home.


----------



## AlaskaGuy (Jan 29, 2012)

> Do not try this at home.
> 
> - DS


Your link is no good, at least it doesn't work for me.


----------



## DS (Oct 10, 2011)

Working on it… apparently I don't know how to embed video… heheh


----------



## DS (Oct 10, 2011)

The link should work now


----------



## wormil (Nov 19, 2011)

> The idea behind the wire inside the dust collection pipe is that charged dust particles inside the pipe will bump into the wire and dissipate the charge to ground before they can develop a high enough voltage to spark a fire.
> 
> You aren t "grounding a plastic pipe" as was previously suggested.
> DS


Not true. By some opinions you aren't grounding anything but static can build up on PVC just as it builds on a balloon, and the claim is that you are grounding the pipe. Papadan stated earlier that all DC manuals instruct you ground the ductwork, he was partly mistaken, only some manuals claim it's necessary. The dust particles and ground are not in constant contact and the wire is only a tiny volume of the total pipe, so even if it is possible to ground PVC, I'm not sure on the effectiveness. But in the end, fine particle count inside the pipe is never going to be high enough to cause an explosion.



> Oakcraft Cabinets in Phoenix had a dust collector fire/explosion at their facility four or five years ago.
> It was devastating. Fortunately they recovered and are moving forward.
> - DS


I was under the impression that commercial DC ductwork had to be metal. And if they are metal, what does that say about the effectiveness of grounding duct? And are the explosions happening inside the pipes or inside the collector? Those big commercial jobs are sucking up more dust in a minute than I make in a month. Even the one for our HS was 2 stories tall and all metal duct.


----------



## DS (Oct 10, 2011)

At Oakcraft, all the metal pipe came completely unraveled in the explosion and the bag house burned to the ground. Even with the grounding, and the spark arrest system, it can still happen.

The Oakcraft incident, I believe, was traced to someone cutting something that hit metal on metal and the ember entered the dust collector. This would NOT have been static discharge that started that fire.

Regarding static electricity: It is the static DISCHARGE that creates the spark, not merely static. When there is a blue spark you are looking at about 6000 Volts minimum. It can be well over 200,000 volts as well. If you can discharge the static at lower voltages before it reaches this extreme, you can avoid a spark that could potentially ingnite a fire.

In this matter you have two options; 
1) Prevent a charge from building - e.g. lower the surface tension (treating surfaces with fabric softener or using anti-static plastic which literally uses the surfactant in the plastic formula) In an ESD-Zero environment, literally EVERY surface is conductive and static can never build up. 
or, 
2) Discharge the static charge in such a way that prevents a spark - BEFORE it reaches extreme levels. e.g. wire in the pipe, metal pipes, spark arrestors, etc. Smaller charges can build but are then dissipated before a spark can occur.

Conventionally, these extra steps are not considered necessary until the dust system is larger that a certain number of cubic feet in volume. (100cf?


> 1000cf


? I don't recall now) 
By that thinking, a hobbyist setup will hardly need to consider these options as strictly necessary.

Will a spark in your home DC still ignite a fire? It is extremely plausible that it could. 
Best to take some basic prevention steps than face the alternative.


----------



## wormil (Nov 19, 2011)

If the oak craft explosion had nothing to do with static, why did you bring it up? Were you trying to imply it was static while knowing it wasn't? Sneaky.

All that blabber doesn't change anything I said. You cannot ground an insulator and the dust concentration in your little home ductwork is never going to explode. A hot ember starting a fire is a possibility but running copper through your ductwork is not going do anything about that.


----------



## DS (Oct 10, 2011)

Rick, I suppose I failed to recognize that this thread was actually an argument… maybe it was just you.

I was pointing out the following;

Saw dust, when suspended in air, is highly volatile and can explode.
Electro-Static Discharge (ESD) is real and can and does spark fires under the right conditions.
Steps that prevent ESD are worthwhile even in small DC systems.
The OP can treat his planer with a surfactant such as fabric softener to reduce the build up of static electricity at the DC port. (BTW, you can also just wipe a metal surface like your planer with a dryer sheet instead of misting with a liquid that could cause rust.)


----------



## oldnovice (Mar 7, 2009)

Just for grins, here is a deliberate sawdust explosion!


----------



## wormil (Nov 19, 2011)

> Rick, I suppose I failed to recognize that this thread was actually an argument… maybe it was just you.
> - DS


 You began this tangent by claiming I was wrong, which is a funny way to not have an argument. Maybe it's not me.


----------



## oldnovice (Mar 7, 2009)

You guys are arguing about dust! Get serious, how about *North Korea*!

*This discussion has yet to reach an explosive point* and we should keep it that way!


----------



## Mike_D_S (May 3, 2012)

Larry,

The conversation kind of wandered a bit, but I have had the same issue you have. 95% of the time I can run my 734 with no static issue, but once in a while I'll get a zinger of a static shock when I go touch the planer.

So rather than mess around with ducting grounding or anything else, I made up a 12 ft piece of light gauge wire with alligator clips on each end. When I'm having the issue, I just unroll it and clip one end to the planer and the othe end to the DC frame which resolves the issues. When I'm not using it, it hangs on a nail all rolled up neatly.

You've got some similar advice earlier in the thread, but I thought I'd throw in my solution.

On a side note, in my case, the static charge seems to be building on the planer and not me. I only get a shock when I touch the planer and not the DC or other grounded items, so it leads me to think I'm the ground in this example.

Mike


----------



## jacksdvds (Jun 13, 2015)

> Even if it grounded its going to happen no matter what you do. It s you not the machine. I usually slap my hand to metal before I touch it, if I think to.
> 
> - alittleoff


NUFF said!


----------



## Carloz (Oct 12, 2016)

> Ground the machine, add some moisture to your shop, DON T TOUCH THE METAL, ground yourself before you touch anything. In late spring to late fall here in Arizona it is constant static shocks every time you touch metal. The shock is probably you and not the machine.
> 
> - Jack Lewis


It is your shoes. Get something with a more conductive soles.


----------



## oldnovice (Mar 7, 2009)

When I use my Craftsman shop vac if I touch my table saw i can be sure of getting shocks, plug in or not, and the 
larger particulate matter cling's to the hose.
When I do thee same cleanup with the household Filter Queen vac I do not get shocks from my table saw or any other tool in my shop, and the hose does not grab any particles.

Just for grins comparisons:
Craftsman shop vac = plastic body and hose, HEPA pleated filter

```
$16/filter, 65db noise,  third shop vac in 40+ years<br />Filter Queen = metal body, vinyl hose, HE PA conical filtefilter
```
 $15/12 filters, 45db noise, 40+ years old


----------



## ArtMann (Mar 1, 2016)

> Conventionally, these extra steps are not considered necessary until the dust system is larger that a certain number of cubic feet in volume. (100cf?
> 
> 
> > 1000cf
> ...


It is not the volume of dust that is important. It is the density of the dust that is needed to sustain a flame wave front. The dust must be so dense that you can't see through it. I don't think very many home or small shop dust collectors can even support that density of dust. The system would have long since failed to function. Look at the video someone else linked to. They created an explosion by blowing a canister completely full of dust into the air. They couldn't do it with an air supported stream of dust.


----------



## DS (Oct 10, 2011)

ArtMann, I think we are saying about the same thing.

When I referenced Cubic Feet of volume, I was referring to the dust collector system, (capacity), not the dust load itself, per se'. I was trying to remember what the city reg's stated from back in 1998 (The last time I had to oversee a large DC system installation). Above a certain size of system the spark suppression requirements were a lot more rigorous.

The current shop I work for recently expanded its DC system and the current city reg's required the stricter spark suppression standard on an even smaller system than the one in '98. (I was not directly over the project this time)

It stands to reason that a larger system would be drawing from multiple sources and could aggregate such dust loads to create the circumstances you mentioned.

Still, I remember taking a box of off-fall scraps on a camping trip for firewood and tossing the small handful of saw dust from the bottom of the box over the campfire and achieving a substantial fireball. I am not sure it takes very much dust density to get a very negative result.

(BTW, check the link in post #33)


----------

