Belt sander static electricity problem

Disregard most of post 17, I'm not even sure what I was saying :(
 
I can't emphasize it enough. Taking off your shoes to make yourself as the grounding path (for static, or otherwise), while at the same time operating an electrically powered machine, is NEVER a good idea. If you make yourself as the grounding path for static, you've also made yourself an alternate ground path for the AC. If you do this in your own house/shop, that's at your own risk. Advising others to do it is foolish. It's the kind of 'advice' that'll eventually kill someone.
 
Again, two different types of electricity. in a way

I understand your point but I have also worked with electricity for a long time and what is happening has no relation to the power driving the machine. Static shock from the grinding process will not kill you.
 
knifenut1013 said:
Again, two different types of electricity. in a way

I understand your point but I have also worked with electricity for a long time and what is happening has no relation to the power driving the machine. Static shock from the grinding process will not kill you.
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That's correct. Static won't kill. That's not the point. Again, you're assuming that nothing else will ever go wrong with the machine.

The point is, IF the ground connection from the machine to the AC outlet ground (the third, larger prong on the plug) is ever broken or inadvertently disconnected (it does happen), it leaves the operator as the ONLY ground path for any and all electrical current flow from the machine to ground. If it's only static, no big deal. If it's 120VAC, it definitely CAN KILL.

I've repaired ground faults on machines where the ground wire in the cord was broken (right at the junction with the molded plug; this is where the cord gets a lot of flex/stress from being pulled/yanked out of the outlet). When the ground path is taken away, in many cases it will leave AC voltage 'floating' on the chassis/frame/case of the machine. This is how we discovered we had a problem with these machines; operator got shocked. The same situation is sometimes created when people use those 'adapters' to plug 3-pronged cords into 2-pronged outlets. That grounded 3rd prong isn't available as the 'safety' anymore. It's OK, as long as the equipment is in proper working order. But, if it isn't (if there's a power supply short to the chassis), then who/whatever first 'grounds' the chassis becomes the path for current flow.

As has been pointed out earlier in this thread, there are much better and safer ways to deal with static. Sharpening knives on electric machines while bare-footed is a bad idea, any way I see it.
 
I'm not arguing with you my friend, I clearly understand your points and have seen all kinds of crazy electrical issues myself. But static build up from grinding acts much differently that a electrical issue with the machine and will shock you in different ways. 120 kill you? possible but I can grab 120 lines without being killed.

This issue is common and the arguments that go along with it are common also. The static is from the belt and knife making contact, this postitve charge is looking for a negative path and will find it in either the grinder body or earth ground. You touching the ground causes immediate dissipation of the static charge.

It does not matter if your wearing shoes or not with AC, your getting shocked much harder and you will know the difference.

Again I'm not trying to argue but this topic always gets way off topic with "it could be" and not what is really happening.
 
knifenut1013 said:
I'm not arguing with you my friend, I clearly understand your points and have seen all kinds of crazy electrical issues myself. But static build up from grinding acts much differently that a electrical issue with the machine and will shock you in different ways. 120 kill you? possible but I can grab 120 lines without being killed.

This issue is common and the arguments that go along with it are common also. The static is from the belt and knife making contact, this postitve charge is looking for a negative path and will find it in either the grinder body or earth ground. You touching the ground causes immediate dissipation of the static charge.

It does not matter if your wearing shoes or not with AC, your getting shocked much harder and you will know the difference.

Again I'm not trying to argue but this topic always gets way off topic with "it could be" and not what is really happening.
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You don't expect the machine to be ungrounded, of course not. But it's a better safety precaution to NOT make yourself a path to ground, just in case.

As for the case with static electricity (i.e. charges that do not move/flow), I'm not sure grounding yourself would help. Those positive charges want to move to a location with less charge, as in higher pressure air moving toward lower pressure. You, yourself, are not positively charged, so the charges want to move to you, hence the shock. The charges would also like to move to ground, which is also "chargeless." If you are grounded, then the charge is still going to want to move to you anyway and then go to ground, so theoretically that's not going to help.

A better idea would be to ground the platen with an alligator clip and a wire or something like that. That way any charge buildup will go straight to ground.
 
knifenut1013 said:
I'm not arguing with you my friend, I clearly understand your points and have seen all kinds of crazy electrical issues myself. But static build up from grinding acts much differently that a electrical issue with the machine and will shock you in different ways. 120 kill you? possible but I can grab 120 lines without being killed.

This issue is common and the arguments that go along with it are common also. The static is from the belt and knife making contact, this postitve charge is looking for a negative path and will find it in either the grinder body or earth ground. You touching the ground causes immediate dissipation of the static charge.

It does not matter if your wearing shoes or not with AC, your getting shocked much harder and you will know the difference.

Again I'm not trying to argue but this topic always gets way off topic with "it could be" and not what is really happening.
Click to expand...

I'm not arguing about where or how the static is generated (by belt/blade contact). That's the obvious part. But clearly you don't understand what you're setting yourself up for, if you claim you can 'grab' 120 VAC and never be hurt/killed by it. It simply means you've been lucky thus far (and that you probably KNEW not to ground yourself while you were 'grabbing' it). Sure, many of us have inadvertently touched 120 and felt the little 'tingle', before pulling away. But a lot of people get hurt when they 'grab' it accidentally (and unexpectedly), when they happen to be touching or leaning against something that's grounded.

And on the subject of going 'off topic', I believe it's worthwhile if some of the so-called 'advice' given is reckless and/or dangerous. For what it's worth, I don't believe that's ever off-topic.
 
The thing about discharging static, that makes it such a PITA, is that it discharges rapidly (painfully).

There's a whole industry devoted to products which are made to do this in a safer, more controlled way. They use 'electrically dissipative' materials, combined with high electrical resistance, to provide a safe pathway for static to discharge to ground. The idea is to provide enough electrical resistance, so as not to allow excessive (dangerous) current flow, while at the same time allowing static to dissipate through the material to a known good ground. 3M makes a lot of these types of products.

Anti-static wrist straps: Electrically dissipative fabric band for the wrist, connected through a resistance (1 megohm or more) to a known good grounding point (like the earth ground connection in an AC outlet).

Anti-static floor mats: works the same way as the wrist straps, except you stand on it. Sometimes, these include an ankle strap connected to the mat, if shoes prove to be an issue.

Anti-static touch pads: Same deal, except it's a small pad (similar to a mouse pad) that you can place on your bench/desk. It's connected (again, through a resistor) to a known good ground. Touch it frequently to discharge static built up on you. This sounds like a possible good solution for working at the grinder, if you're concerned about being 'corded' with a wrist strap while you work.
 
I have experienced the same problem from time to time. I found that an anti-fatigue mat and static guard spray eliminated the vast majority of the small shocks I was getting. Grinding barefoot sounds like a good way to lose a toe, or worse.
 
Still got all me toes :)

I would say a ground ankle strap sounds like the best "out of the way" idea. Also will keep your feet from being unprotected ;)
 
Not wearing shoes to avoid static shock while grinding, is a lot like not wearing your seatbelt because it chafes your neck, while driving.

My vote goes to alternative static reducers... ever try grinding in chainmail? Not sure if that would do anything at all, but it would look damn cool.

Rick
 
Just wear a static band that is grounded. I use a tv cable wire thats hooked to a brass rod I put in the ground. Works great. No more cuss words or dancing around the shop.
 
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Old thread, but still relevant.
Guess I've been lucky to never been shocked while using a belt sander at work. They're all electrically grounded, have metal platens, I think metal rollers, and maybe the belts they use are conductive too. I also wear redwing boots with insulating soles.
My guess is, some sanders are designed to dissipate static, some not.
 
there is a product called static guard available at the grocery store in spray cans you can find it usually around the laundry detergent. spray the belt and behind the belt on the platen, problem solved I have used it for years
 
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