Where are you located? I've got a handful of static wrist straps, I'd be happy to donate one. I'm in Calgary
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Belt Sander Electrocution
- Thread starter thestelster
- Start date
Hi Ken, thank you that's extremely thoughtful. But I'm in the Toronto area. Amazon has them for $10.00 or so. I'll probably go that route.
Thank you.
Thank you.
slow-poke
Ultra Member
Completely agree with this.
Grounding yourself just seems like a bad idea, I certainly wouldn't do it with a solid ground as described seems like the exact opposite of what electricians do using nonconducting ladders and mats. ESD strap possibly, but that also seems hazardous if the lead gets caught in the works.
Electricity only flows because of difference in electrical potential. You have two choices. Isolate from the unit or become part of the unit. All sounds strange to me. If it is not part of the electrical grid standing on a conductive mat tied to the machine is the preferred way to go. If it is a grid source potential, then take a conductor to the panel ground and if the breaker does not trip. then it is the machine generating static and you need to bleed off the static being generated or as stated become part of the machine.
TonyK.
Grimsby Ontario Canada.
TonyK.
Grimsby Ontario Canada.
Yes, we grounded the cabinet body of ours, to address this.
Stelios
Are you getting a static discharge shock or is a continuous current flow? As many have suggested, a missing ground to the motor and therefore, metal frame of the sander may be a factor. There is a test on medical equipment that I used to do called a leakage current test. It involved opening the grounding wire and measuring the current flow to the chassis in all functions. It had to be below a certain level, depending on the type of equipment. The reason for this check was to ensure, that, should the grounding circuit become jeopardized at some point, a patient or user is not going to be subjected to current shocks such as you may be experiending. In the case of pre "double insulated" tools, (ie plastic and 2 wire power cords), where tools had metal housings, the ground integrity is paramount. It sounds like you have checked that. But, again, as someone suggested, ensure that ground integrity has not been lost between the panel and the sander. Ensure that the white and black are not mixed up in some power cord/extension cord/switch box, etc. Anyone ever change a light bulb and get a shock from touching the light bulb base? It often came down to someone repairing a lamp cord and mixing up the hot and neutral.
Please test the outlet with one of these (or similar) to ensure the issue is not before the sander.
It could be a fault in the motor. But these type of issues would mean that with the motor running, no metal on the sander, and if you touch any metal part of the sander, you would get an electrical shock (as opposed to a static shock)
However, if it is simply a static shock you are getting, then I feel, like others, the tape on the table is the issue. In lieu of grounding yourself, can you clip onto the metal pieces with an alligator clip or metal magnet? Since this appears to be a fairly isolated issue, I would try to address the issue rather than finding a work around it like a grounding strap. I have never gotten a shock from my sander regardless of what I am sanding.
Wish I was closer. Interesting issue.
Shawn
Are you getting a static discharge shock or is a continuous current flow? As many have suggested, a missing ground to the motor and therefore, metal frame of the sander may be a factor. There is a test on medical equipment that I used to do called a leakage current test. It involved opening the grounding wire and measuring the current flow to the chassis in all functions. It had to be below a certain level, depending on the type of equipment. The reason for this check was to ensure, that, should the grounding circuit become jeopardized at some point, a patient or user is not going to be subjected to current shocks such as you may be experiending. In the case of pre "double insulated" tools, (ie plastic and 2 wire power cords), where tools had metal housings, the ground integrity is paramount. It sounds like you have checked that. But, again, as someone suggested, ensure that ground integrity has not been lost between the panel and the sander. Ensure that the white and black are not mixed up in some power cord/extension cord/switch box, etc. Anyone ever change a light bulb and get a shock from touching the light bulb base? It often came down to someone repairing a lamp cord and mixing up the hot and neutral.
Please test the outlet with one of these (or similar) to ensure the issue is not before the sander.
It could be a fault in the motor. But these type of issues would mean that with the motor running, no metal on the sander, and if you touch any metal part of the sander, you would get an electrical shock (as opposed to a static shock)
However, if it is simply a static shock you are getting, then I feel, like others, the tape on the table is the issue. In lieu of grounding yourself, can you clip onto the metal pieces with an alligator clip or metal magnet? Since this appears to be a fairly isolated issue, I would try to address the issue rather than finding a work around it like a grounding strap. I have never gotten a shock from my sander regardless of what I am sanding.
Wish I was closer. Interesting issue.
Shawn
The tape is the only real distinction to other belt sanders which are so common & static shock just never seems to arise in discussion. Some use aluminum wheels, but many use rubber / plasticized wheels, so that cant be the issue. My 1x42 Delta has plastic wheels.
Maybe temporarily remove tape just to see if it makes any difference to zapping. If you really need tape there (what was the original reason again?) consider a metallic based tape. I use this aluminum tape (maybe called flashing tape?) to protect parts from lathe jaw grip clamping. It is very consistent in thickness & has a good adhesive. I don't like futzing with copper shims & they can have unequal thickness over time but that's another topic. Now whether the adhesive on the tape is acting as a bit of an insulator I can't say 100%, but there are simple ways around that. But I think I used my electronic edge finder with the tape in place. The thought of wrist-banding yourself to any kind of machine just strikes me as -yeesh- be careful
A bit off topic, but maybe indirectly useful information. I've tossed a couple bad power strips myself. I'm not sure the C in CSA stands for what it used to stand for.
Maybe temporarily remove tape just to see if it makes any difference to zapping. If you really need tape there (what was the original reason again?) consider a metallic based tape. I use this aluminum tape (maybe called flashing tape?) to protect parts from lathe jaw grip clamping. It is very consistent in thickness & has a good adhesive. I don't like futzing with copper shims & they can have unequal thickness over time but that's another topic. Now whether the adhesive on the tape is acting as a bit of an insulator I can't say 100%, but there are simple ways around that. But I think I used my electronic edge finder with the tape in place. The thought of wrist-banding yourself to any kind of machine just strikes me as -yeesh- be careful
A bit off topic, but maybe indirectly useful information. I've tossed a couple bad power strips myself. I'm not sure the C in CSA stands for what it used to stand for.
Honestly, I can't remember why I have the tape there. I'll remove it and see what happens. But often I need to shorten a screw or something that I can't use the grinder rest, so I'm holding the part up mid belt, and when my hand gets near the cover, I get a zap.
The wheels are solid rubber.
There is also quite a bit of belt tension pushing back on the platten. Can the friction and dust be the cause?
Also, those wrist bands incorporate a 1megohm resistor in series for safety?
slow-poke
Ultra Member
Thanks for posting.
The crazy thing is that crappy bus bar actually has a certification sticker, some of the crap with the meaningless CE mark stickers is even worse, I have tested 5V USB type chargers with 120V Hot connected directly to the 5V output! It might be a fake or rubber stamp type sticker?
We did all of our product certification here in Canada, that being said we had offers from overseas to put a sticker on every unit for a tiny fraction of the price we pay here with no strings attached so you can't trust the stickers anymore especially the ones with a bunch of official looking marks that actually have no meaning here.
WARNING: Counterfeit ETL certification mark on Luxes Lighting luminaires (17359) - Electrical Business
September 30, 2016 - Intertek has issued a warning about portable luminaires (model 17359) from Luxes Lighting Co. bearing counterfeit Intertek certification
www.ebmag.com
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Jswain
Joe
Just thinking now I have mine on polyurethane casters so that's probably exactly why.
Ok, so I removed the tape from the rest. And grinding a piece of aluminium...no static jump.
Grinding the same piece mid way up the belt, I get zapped.
So question. When I hold the piece on the rest am I not grounding my self to the machine, just like those ESD wrist bands?
And right now, I was grinding that piece up mid belt where I got zapped, but this time put a finger on the rest. No zapping.
Grinding the same piece mid way up the belt, I get zapped.
So question. When I hold the piece on the rest am I not grounding my self to the machine, just like those ESD wrist bands?
And right now, I was grinding that piece up mid belt where I got zapped, but this time put a finger on the rest. No zapping.
Clearly the belt generates static. A non-conductive work piece won't transfer that static charge to you, but a conductive one will. If the work piece itself is touching the frame, it can discharge the static directly. But if it is not, then the charge has to drain through you. Either a wrist band or a zap.
Probably it is not very dangerous. It takes a lot of static to be harmful because unlike a short from the mains, the total power is limited. Static voltage can get very high, but the amperage is limited. But I'm sure it is annoying!
To address the root cause, check the belt tension. As others have mentioned, anti-static spray on the back of the belt, and changing the rollers
Probably it is not very dangerous. It takes a lot of static to be harmful because unlike a short from the mains, the total power is limited. Static voltage can get very high, but the amperage is limited. But I'm sure it is annoying!
To address the root cause, check the belt tension. As others have mentioned, anti-static spray on the back of the belt, and changing the rollers
Yes, but that's not a fix. At least not one I could recommend.
Neither of those are a fix. They are just a way to dissappate the charge through you. You don't really want that. You want to stop the charge from building up in the first place. Steel rollers might kill it, rear brushes might kill it, grounding the frame might kill it.
I can't see anything in your photos - that's not like you at all. Can you take a few photos of the entire system as well as whatever closeups are relevant?
Do you not see the spark in the video?
I'll take pictures tomorrow.
The frame is grounded. To the motor, to the switch, to the 3-prong electrical cord, to the outlet which not only has a ground wire going back to the panel, but the EMT conduit as well.
I'll look around on-line and try to find a static brush that I can attach to the back of the belt.
What video? It is a still image on my screen.