Dust collector grounding?

[Craig McCormick]

I bought a used dust collector about a month ago that did not come with any instructions. It did come with just enough hose and fittings that I can hook it up to my planer. The hose is about 8' long. What is the proper way to ground it? Do I need to ground it at all if I am just using 8' of hose between my collector and my planer?

Thanks,

Craig

[Randal Stevenson]

Is this a dust collector, or a cyclone?

Home dust collectors, (generally) have been proven to not generate the correct mix of particulate mater to air, for an explosion to happen.
Cyclones generate more turbulance, and more static (don't have one, too small of shop), so I can't comment on them.

The other reason people add grounding, is so they won't get a shock off their pipes (doen't always happen and shouldn't with your flexible line).

[Ken Fitzgerald]

In researching before buying my cyclone I found several articles. One was a scientific study. THERE ARE NO KNOWN CASES OF STATIC CAUSING AN EXPOSION OR FIRE IN A HOME DC.....CYCLONE OR OTHERWISE. The main reason for grounding the dc and pipe is to prevent static shock to people. I, for one, don't enjoy shock so I ponied up for the metal pipe. A lot of the problem is related to the geographical area and the atmospheric conditions there. We receive an average annual moisture total of 12". 2" less and we'd be classified a desert. Consequently our average humidity is much less than other areas of the US. I don't like static shock so I used metal pipe. I just don't want to be jerking or jumping due to static discharge while operating power tools or any other time for that matter.

I'd be more concerned about the material making up the impeller. If you have a steel impeller and happen to suck a screw into the dc...sparks could be sucked into the bag/barrel and a fire occur later due to that smolkering spark.

JMHO.

[Alan Schaffter]

I'd be more concerned about the material making up the impeller. If you have a steel impeller and happen to suck a screw into the dc...sparks could be sucked into the bag/barrel and a fire occur later due to that smolkering spark.

JMHO.

Not likely to happen either- the kind of spark that would possibly be generated would be short lived, and with the air flow, the heat is not there to ignite anything. I have a 3 hp DC blower with a 14" steel impeller hooked to a Pentz design cyclone in a push-through configuration. Dust, chips, and an occasional nut, screw, or other metal items regularly impact the impeller blade before going into the cyclone. In over 8 years of use, I never had a fire or even a hint of a detectable ember.

[Victor Stearns]

Craig,
Here is a website that has great info.
http://billpentz.com/woodworking/cyclone/ducting.cfm#StaticElectricity
Good Luck
Victor

[Chris Padilla]

Forget about grounding plastic: not easy to do and not necessary.

[glenn bradley]

I don't do it. This has been discussed to death and no one has presented a single credible report where dust collection and static alone caused a problem. One ambitious science-guy did actually get dust to ignite in a lab environment. The atmosphere he had to create was so dense that nothing could breath it.

[Tom Veatch]

...One ambitious science-guy did actually get dust to ignite in a lab environment. The atmosphere he had to create was so dense that nothing could breath it.

Dust explosions can and do occur. This one shook my house from about 5 miles away. (http://www.wichitagov.org/CityOfWichita/Templates/TwoColumnImageGallery.aspx?NRMODE=Published&NRNODEGUID=%7bF1818B64-EF5E-47D7-AD5F-7A4652A21DBF%7d&NRORIGINALURL=%2fCityOffices%2fFire%2fPhotos%2fGal lery1%2ehtm&NRCACHEHINT=Guest)

But as you point out, the conditions are such that the area/volume is nearly uninhabitable. The figures I've seen on the particulate concentration necessary to support a flame front is such that visiblilty in the dust cloud would be less than one meter.

So, unless you have a very small shop, if you can see the far wall, you don't have an explosive concentration of airborne dust particles. (That doesn't, of course, address the conditions inside the dust collector or ducting.)

[Robert Payne]

As others have said, you cannot "ground" plastic pipe or PVC flexible duct because these materials are insulators. The static charge buildup can be dissapated at each machine if you connect the spiral coil wire inside the flex with a grounding wire to each machine. I don't bother, but if you are in a chronically low humidity area, then it might make sense. I use PVC S&D pipe for my DC ductwork and don't worry about the static charge as it is minor.