Gee - I'm really sorry you asked that question. Prepare for a lot of pro's
and cons. For in depth information, search for info. Otherwise, *some*
people content that static electricity could generate a spark which will
ignite the dust in the hoses and start a fire in your workshop. Others
quickly point out that there is NOT ONE documented case of this happening in
a home workshop. Dust explosions in a commercial environment are another
matter but still not relative to the dust collector and static electricity.
If you want to do it, run a copper wire through the hoses and ground them. I
did it that way and it was a real PITA. When I moved and redid the system, I
did not ground the hoses/pipes.
IMHO, ignore the grounding - it really falls under the urban legend heading.
If you don't think you have a static problem in your workshop... what do
you think is holding all that dust on the walls?
HOWEVER... having said that, getting a dust cloud to explode in a home
workshop environment is next to impossible.
I agree with Vic. I went to all the bother of running a ground wire through
an extensive duct system. I dont think I would do it a second time.
FWIW, I do recall seeing a mention of this in Sandor N.'s book on dust
collection a few years back. He stated in that edition that insurance
companies said they have documented evidence this does happen. Whether
you believe that or not, it might be wise to be sure you don't do
something the insurance companies can use to avoid paying out on a
There's a new edition of that book out, I guess. I wonder what he says
Anyway, on Bill Pentz web site on dust collection
(http://billpentz.com//woodworking/cyclone/index.cfm ) I believe he
says something about using metallic tape for grounding as being easier
My shop vac pushes enough air to ionize ne-2 neon lights and make
them glow. It gets very dry here in the midwest during the winter.
This is NOT urban legend. We see sparks and grain dust explosions
every year. It's not a big stretch to imagine a fire from sawdust.
People in this newsgroup have ignited it with sparks or hot metal
Vic Baron wrote:
In order for an explosion from a static electric discharge to ignite
sawdust in the air, the concentration in the air would need to be on the
order of not being able to see your hand in front of your face! It is
not possible to have that concentration of sawdust in the air and still
I have no personal experience, this is according to everything I've ever
read on the subject. Grain explosions occur in very confined areas in
silos with very high concentrations of dust, to a degree simply not
possible in a shop (commercial or hobby).
Mike Berger wrote:
if you have evidence of a static electricity induced explosion in a
home shop dust collection system, post it here. you'll make history-
it will be the first and only time such evidence has come to light.
wanna be famous? go for it....
Static charge and sawdust fires from hot metal are two different animals.
Grain and dust explosions in commercial environment are not the same thing.
I repeat - sawdust explosions from static charge in a home workshop are the
stuff of urban legend.
" 'Our preliminary information shows that there have been 150 dust
explosions resulting in more than 80 deaths over the past two decades,' CSB
representative Dan Horowitz says. Hoyle, who is heading the investigation,
traveled to Baltimore in October to attend a meeting of NFPA's Technical
Committee on Handling and Conveying of Dusts, Vapors, and Gases, which has
jurisdiction over NFPA 654."
You need to do something. It would seem half the explosions in the US are
happening where you live.
The folks at NFPA will remind you that proper particle composition, size,
dispersal but overall confinement, and the availability of oxygen don't
guarantee an explosion. Even the ignition source has to fall within a fairly
narrow set of parameters.
That's why dust explosions so rare. Now explosions resulting from "dust"
off-gassing, like plastics and such are more common, but they're not really
dust explosions, nor are they so picky in their conditions.
I have no knowledge of static electric build-up causing explosions.
However, please be advised that static electric in an ungrounded vacuum
system can be substantial. Just last week, my son "fried" a Dewalt
plunge router while using its dust collection connection in
conjunction with his home vacuum system.
He was running the router while connected to his operating home vacuum
sytem. The plastic hose connected to the vac and the router was draped
over his shoulder. After running the setup for only 10 to 20 seconds,
he felt a tremendous shock in his shoulder at which time the router
stopped running. Previously, he had used the router extensively with
the home vacuum in another location where the vacuum outlet was
The router was deemed not repairable by the Dewalt service center. The
center personnel stated that the router had been damaged by an external
electric source; the router checked out as properly insulated.
Please be careful.
If you are using plastic pipes the idea is to eliminate static buildup
caused by the material in the pipe rubbing on the walls.
It should be sufficient to ground the hose clamp at the dust collecor
end. If the hose attachment is metal and in contact with the blower
motor housing it is likely to be grounded already.
A simple check is to run the system and suck up a bunch of dust, then
touch the hoses while in your stocking feet. If you don't get a jolt
you can probably leave it alone.
You'd be surprised how much static is built up on the system. If you're
moving it around the shop at all you'll want to ground it so you don't get
shocked every time you touch it... and continuously while your touching it.
As the other reply points out people worry about dust explosions and such, I
agree with him I don't think it's a real danger.
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