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Dust extraction static

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letgomywago

Senior Member
Location
Washington state and Oregon coast
Occupation
residential electrician
So I wired a guys woodworking shop and he was talking with the GC about the dust extraction system. His concern was the normal dust extraction pvc piping building up static and igniting the dust inside of it. His idea was to use a bare 6 taped to it to equalize the potential. Idk if that'd do much since the pvc is foam core but it may I'm not sure. Anyway other than doing a metal piping has anyone had this ever be an issue. This is more of a general wondering for me since I'm sure that some systems have been engineered to address this issue or that it's been proven to not be an issue.
 
he should find something else to worry about. Here, maybe one of these:

1. plastic water pipes
2. Lead in brass fittings
3. off gassing of spray foam/auto interiors/plywood glues
4. microplastics from synthetic fibers
5. carbon monoxide from his cooking stove
6. fluoride in the water

:ROFLMAO:
 

letgomywago

Senior Member
Location
Washington state and Oregon coast
Occupation
residential electrician
he should find something else to worry about. Here, maybe one of these:

1. plastic water pipes
2. Lead in brass fittings
3. off gassing of spray foam/auto interiors/plywood glues
4. microplastics from synthetic fibers
5. carbon monoxide from his cooking stove
6. fluoride in the water

:ROFLMAO:
I'm just glad he didn't go all EMF causes cancer on me haha.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
We had a similar thread about this many years ago where someone wanted to bond PVC piping. I don't that that anyone was able to offer any evidence that this should be a concern. Just an over thought solution to a non-existing problem.
 

Fred B

Senior Member
Location
Upstate, NY
Occupation
Electrician
Worked around several wood shops. The PVC vac lines present an even bigger static issue than the metal that can more easily naturally discharge buildup. The PVC that did not have a discharge wire run would build up so much static, fine material would cling to outside of pipes and enough charge that the hair of your arm would stand up and shock as you got close. It also can buildup enough to arc and if in presence of flammable products can cause ignition.
A number 6 wire for this is likely overkill, as, if dissipation is continuous there is very little current. Guidance is usually just large enough to handle conditions if installation not related to current. Aerosolized w ood dust just like even flour dust can explosively flash ignite under the right conditions.

NFPA 77 has guidance related to static discharge

One source of grounding in a vac pipe:

wood dust explosive nature:
 

retirede

Senior Member
Location
Illinois
I have PVC pipe in the suction of my dust collector. I ran a #14 bare copper along with it, attaching it with a very short screw every few feet. It terminates on the metal housing of the vacuum pump. I have had no issues with static buildup.

The #6 is over kill….its purpose is to prevent static buildup, not to clear a ground fault!
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
This can be a real issue if you are doing sanding operations, so some method of preventing static build up should be considered. Sanding is about the only type of process that produces particles in the size range needed for a dust explosion. Sawing, turning, planing and other woodworking operations do not produce wood particles small enough to have a dust explosion.

The idea in the previous post sounds good, if you actually have combustible dust.
You don't need much to prevent static buildup....anything less than one million ohms will do the job, but as I recall NFPA 77 requires not more than

Note, even without the issue of combustible dust, there can be a static shock hazard from metal parts connected to the PVC dust collection piping and bonding will eliminate that hazard.
 
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