Static discharges with the SS dust collector

artlinux · Post by **artlinux** » Sat Dec 21, 2013 1:02 pm

In reply to WmZiggy question about grounding of the SS thickness planer:

The planer is powered by 120Vac via a three wire plug with a U ground pin. Unless the ground connection is defeated by some missing connection to the building wiring system, the planer is effectively grounded.

In a simple test, I looked for a metal part or screw on my planer that was not connected to the U ground pin but only found grounded metal parts - just as expected.

The connection to the SS way tubes will have no impact on the ability to have a properly grounded planer.

reluctant43 · Post by **reluctant43** » Sat Dec 21, 2013 9:36 pm

Reading all this makes me think the answer is to ground the plastic tubing going from the SS dust collector to the DeWalt 735 Planer. I say this because the planer itself is grounded through the three prong plug and the dust collector is grounded in the same way. The planer is connected to the dust collector with SS tubing that is insulated from both the planer ground and the SS ground because it is connected with plastic parts. I would have thought there would be some kind of ground because the tubing is coiled on the cement floor but perhaps wrapping a wire around it and attaching the wire to a length of chain that drags on the floor would improve? Any educated guesses whether this will work?

JPG · Post by **JPG** » Sat Dec 21, 2013 10:41 pm

A strip of conductive paint end to end. Ground one end. However the inside will likely still be 'charged'.

skou · Post by **skou** » Sun Dec 22, 2013 3:27 am

OK, when I was in the Army, working on Chinook helicopters, we (or, the crew members) had compressed air vacuum systems. (The compressed air blew into the bag, through a tube, and the flow created a vacuum.) Those HAD to be grounded, because of the explosion "issue." (If you ever get gas, or even JP-5 for your aircraft, it WILL have a ground strap hooked to it.)

Basically, if you move anything through a plastic tube, you'll generate static electricity.

steve

JPG · Post by **JPG** » Sun Dec 22, 2013 9:09 am

skou wrote:OK, when I was in the Army, working on Chinook helicopters, we (or, the crew members) had compressed air vacuum systems. (The compressed air blew into the bag, through a tube, and the flow created a vacuum.) Those HAD to be grounded, because of the explosion "issue." (If you ever get gas, or even JP-5 for your aircraft, it WILL have a ground strap hooked to it.)

Basically, if you move anything through a plastic tube, you'll generate static electricity.

steve

Last I knew the aircraft was grounded before contacting the hose.

There are many sources of static electricity. Not all involve plastics.

dusty · Post by **dusty** » Sun Dec 22, 2013 9:32 am

Like we so often do, we are mixing subject matter because of some similarity in the words being used.

Do realize that the hazards of static discharge in and around an aircraft is quite different than the hazards in and around our dust collection system. The likelihood of an explosion (due to static discharge) on the flight line is many times greater then in the wood shop.

I live in a very dry climate. I get zapped simply as the result of walking across the living room carpet. I feel a static discharge probably everyday that I work in the shop and especially if I have been using the dust collector or have been sanding with a power sander. That shock is most likely to occur when I come in contact with either the dust collector or the table saw (the table saw because it is grounded).

BTW: The only dust collection system I have is the DC3300 and its associated flexible hoses. Well, there is the ShopVac and I do occasionally get zapped there as well.

WmZiggy · Post by **WmZiggy** » Sun Dec 22, 2013 10:21 am

artlinux wrote:In reply to WmZiggy question about grounding of the SS thickness planer:

The planer is powered by 120Vac via a three wire plug with a U ground pin. Unless the ground connection is defeated by some missing connection to the building wiring system, the planer is effectively grounded.

In a simple test, I looked for a metal part or screw on my planer that was not connected to the U ground pin but only found grounded metal parts - just as expected.

The connection to the SS way tubes will have no impact on the ability to have a properly grounded planer.

Now I am not certain why the planer table did not drain static electricity. I do know that it didn't because wood shavings not sucked out by my vacuum were charged, i.e. "standing" all over the place (like pornography, you know static when you see it). I've been on another project not involving my planer, but this next week I will test it with and without a drop wire to the floor.

As to the possibility of an explosion, I choose to be on the safe side. If you are smart you play to safety all the time in the shop, and I don't care what the statistics say about explosions in wood shops. I've never cut off a finger, and I don't know too many who have. Even if the chances are low, you still practice to the highest standard. All the books on vacuum systems for the shops recommend grounding your system for static electricity. I have 25 ' of 4" mainline PVC pipe running across my shop at 700 - 800 CFMs - better safe than sorry IMHO.

reluctant43 · Post by **reluctant43** » Mon Dec 23, 2013 11:04 am

I want to thank everyone for playing with this question. As I mentioned before I am going to try grounding the hose, which I think is the only ungrounded element of my system. I suppose an explosion is remotely possible, even in a small shop like mine, but tell the truth I am mostly trying to avoid getting the hard zaps I was getting when the collector was connected to the 735 planer and when I touched both the hose (to move it out of the way of a board coming through for example) AND the shiney outfeed table. I believe the static charge on the hose was discharging to the grounded outfeed table through me! I have not seen this with other uses of the 3300 but that may be because the planer has a really great fan assist for the chip ejection which may add velocity to the airflow through the hose and enhance the static charge that builds up. Anyway, we have probably beat this to death. I will experiment with a grounding system for the hose and send through a picture of it if it works in a new thread.

BuckeyeDennis · Post by **BuckeyeDennis** » Mon Dec 23, 2013 11:35 am

Has anyone tried an anti-static spray on their dust-collector hose? I don't have a problem myself, probably because I run a whole-house humidifier in the winter, and Ohio is mighty humid in the summer.

Here's a product that looks like it might work: http://www.amazon.com/Staticide-Anti-st ... roduct_top

Kinda reminds me of the old D3 antistatic fluid for vinyl LP's. It sure helped, and the companion Zero-stat guns were even more fun. (Especially for zapping your buddies!

)

JPG · Post by **JPG** » Mon Dec 23, 2013 11:55 am

Make sure ya spray the 'inside' of the hose!:D Aim, turn the air flow on and push the button.

Wonder how long it will 'last'.

P.S. Make sure the propellant is not flamable with a universal motor vac!:eek:

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