Dust/Chip Collector

[L. D. Jeffries]

Hi Gang, Need some advise! Just installed a dust/chip collector system in my "small" shop. Have one central run using clear plastic tubing, wire enbeded along its length. I have "grounded" the end at the blower. Do I need to "ground" the end that is connected to each machine as well? Since all my tools/machines are on mobile bases I am using a plastic quick disconnect on the machine end; reconnecting when I change machines. I probably could research this somewhere but I'd rather ask people that I KNOW will know the answer. Thanks in advance for any help.

[rickd]

hi,

i just got a dust collector and have been looking into setting up a plastic ductwork collection system myself. one of the books i have(from ShopFox), states that the wires should be grounded to each individual woodworking machine as well as to the dust collector itself. So, that is what i am going to do.

like you say, there are experts here on this forum who will no doubt give you an experienced opinion where as i am just going on what i have read here and there.

[stewchi]

I did a lot of reading on that before I bought my DC, I don’t remember all of the sources but I was pretty convinced that the whole things is not really relevant. There was a write up that explained how the charges could form and describes why each method suggested was not very effective and that possibility of a home workshop sized DC causing a fire because of static electricity build up was not realistic or a risk.
I made the whole point muted as I found using metal HVAC ducting was cheaper for my shop than using PVC. The metal cannot develop a static charge so the problem solved itself for me.
I am sure others that have used PVC might be able to give some experience on if static electricity is a problem or not for them.

[Tom Miller]

I have PVC ducting, and I do not have any grounding wires installed. Based on what I've read and understand, even if static electricity were a problem, a single conductor through your pvc is not going to help any.

Regards,
Tom

[LCHIEN]

I've read the final word is no danger from static causing an explosion or fire.

It could build up on the plastic, tho.

I have a HF 2 HP DC, wire reinforeced hose with QC at DC end, slip in plastic fitting at saw end, no problems, but this is in Houston TX, humidity capital of the world.

I'd say the actual danger is nil, you should try it w/o grounding ( alot more convenient) and then do something if it bothers you or somehow makes the DC perform less than you want.

[maxparot]

I have the HF 2 hp w/ canister conversion. My system is piped with plastic drain pipe and no ground wiring.
Yes there is a bit of static build up but nothing I am concerned about. The latest research into the question basically stated that the build up could not be enough to ignite sawdust.

[bdk5]

I'm not an engineer, doctor, or otherwise qualified to comment on this, so I won't be held responsible (I am a lawyer, could you tell?), but Mythbusters tested this myth. The myth was that a construction worker was sandblasting a 6" PVC pipe to clean some paint off of it and it caused an explosion from the static build up. The Mythbuster recreated this myth, sandblasting the PVC. There was barely any build up, let alone enough to cause any kind of explosion. I don't imagine that our use of our dust collection systems even approaches the sandblasting job they did.

[psal2]

and you really believe everything you see on TV...LOL

But I agree, I don't believe the buid up would be significant enough in my little shop with 10' PVC run to create a problem. I do not do production work (8 hours per day) and at best work the machines around 15 hours a week.

[Tom Miller]

Gotta say, though, just this weekend I was getting zapped multiple times by my DC. [B)]

I had a 2.5" hose on my ROS connecting it to a 4" DC line while sanding some panels. Whenever my wrist would come in contact with the hose -- ZAP! But it was mostly just annoying.

I think sanding dust is "worst case" when it comes to generating static.

Regards,
Tom

[mdutch]

Though I agree the issue of fire risk or explosion is minimal, using just my metal-can shop-vac on my BT3k dust outlet is enough to generate seriously annoying (and audible) jolts when I least expect it. I asked myself about solvent vapors, but discounted it, as you wouldn't be working with dust while doing finishing. But I wirewrapped my shopvac hose and chassis grounded it. It's made a big difference in the number of major zaps, and noticibly improved the static-charged sawdust "hair" clinging to the outside of the hose.

[gimpy]

mdutch, my shopvac is doing the same thing. Just noticed it this weekend with the sawdust "hair" clinging to the outside of the hose. My other concern though, is, about a month ago, I actually got "shocked" when I turned the shopvac off. I could feel it (can't think of the exact wording) "rumble" through my fingers. Didn't feel good and scared me. I now use a stick to flick the switch off or just really quickly barely touch it. I don't know if the two are connected.
Shopvac (Ridgid) is only a little over a year old and not used real extensively.

regards, Frank

[preamble]

There are documented cases of explosion / fire caused by static buildup in DC systems.
My shopvac frequently nails me with static discharge. It's so bad that I hold on to the metal handle while I use it to avoid the problem.
So after much reading on the Internet I ran across a post from a guy that solved his problem at work by using metal "duct" tape.
I ran a single line of tape on the inside and the outside of the PVC pipe making sure all connections had continuity. I then ground the curcuit at the DC end (not the tool end).
I've never had an issue with static with this setup. And I have the DC connected to BS, TS, CS, RT and JT.

[mdutch]

quote:Originally posted by gimpy
[snip]...about a month ago, I actually got "shocked" when I turned the shopvac off. I could feel it (can't think of the exact wording) "rumble" through my fingers. Didn't feel good and scared me. I now use a stick to flick the switch off or just really quickly barely touch it. I don't know if the two are connected.

In the words of Robot on "Lost in Space": DANGER WILL ROBINSON!!

Your "rumble" description sounds much more like a 120v AC voltage leak than a static discharge. And AC voltage leaks are deadly. You may have a "rumble" or "tingle" today when it's sunny, but walk up to it in wet clothes or spill your coffee and we may be waxing eloquent about your passing.

I'd suggest RIGHT AWAY you do two things. Go to your favorite HD/Lowes/etc and get a 3-prong plug tester. It's got three lights on it and a little chart that shows how the continuity, phase, and ground of the receptacle is working. Now walk around your shop and plug it into EVERY receptacle you have. Note problems and get an electrician to fix them IMMEDIATELY.

Thing two: Get a GFCI receptacle installed in your shop to protect the plugs you use for powered hand-tools. The electrician can install that as well. If your vacuuum in plugged into a GFCI receptacle and you're getting an AC leak, it will detect it and break the circuit before your heart stops. Which may go a long way toward helping you complete those projects on your list!