ESD proofing

[bsahdy]

hello

i am reading the beginners section and i feel totally lost!! however....

I do some electronic stuff at home, mainly hobby work, but i do work with live circuits and other components that are sensitive.

i work in my room and i just found out its the worst possible senireo. i have a carpet floor and a plastic table top.(the kind you bring for outdoor stuff which you buy from home deopt.) i heard that wearing rubber shoes helps so you dont pick up any static charge from the carpet but when i wear the shoes and while wearing them i rub it on the carpet i see it picks up a charge bec i shock myself against some metal. the plastic isnt either too good bec  when i clean it with a paper towel (rubbing the surface) i hear and feel the static build up like when you wave you hand over a wool sweater!!

i know that really you are suppose to get the proper ESD matting but i dont have the money for that. im looking into cheaper alternatives.

here is what i found:

1)i found that wood is not conductive so it wont short your components out but it doesnt dissipate the electricity. which i dont know why that is a problem? if it isnt conductive what is it dissipating? there is no biuld up?

2) using waterproofing roof material also works. more specifically, butyl-rubber sheet. i read that it is conductive so all you need to do is earth it to the earth plug on your outlet.

3) now i know that Dave hates this option but what about the rubber PVC you could buy for plumbing? its not dissipating but it isnt conductive either.

at the end of the day i was planing on making a wooden workbench and since i already have a roll of the PVC plumbing roll i was going to use that to put over my carpet.

please let me know your thoughts as i am kinda oblivious to this topic.     

[Prime73]

http://www.ebay.ca/itm/2-LAYER-RUBBER-ESD-ANTI-STATIC-GROUNDING-MAT-2-MM-24-X-60-W-GROUND-CABLE-/281178067566?pt=LH_DefaultDomain_0&hash=item417784d26e&_uhb=1

$52 and no headaches. I would suggest to buy a proper esd mat.

[nixfu]

$52 and no headaches. I would suggest to buy a proper esd mat.

I can vouch for that guy in Canada on ebay.  He cut me a piece to exactly the length I needed and charged a great price for it.

[nanofrog]

I've bought from the Canadian seller linked, and can vouch for him and the product being sold. At normal pricing, he's also the least expensive source I'm aware of for North America. 

Another potential alternative, is watch vendors for closeouts. Picked up another 30"x60" mat from All-Spec this way really cheap a few months back (~$22 before shipping IIRC; medium duty, so it was thinner at 0.060" thick instead of 0.080"). Here's what they have left.

May be completely useless links for you though. Going into your user profile and setting your country will help members post relevant links (displays national flag). 

[bsahdy]

hey guys thanks for the links.

although they are cheaper alternative but would my option i posted work? it will only cost me 10 dollors that i was anyways going to spend for a new workbench

can some one also explain why dissipative isn't good enough it also has to be conductive?

thanks

[What_NZ]

Build the wooden desk, it is what I have too.
Use a good antistatic wrist strap when you are concerned about damaging the components you are working on.

Unless you are in a really dry room with lots of static, you shouldn't need an antistatic mat.

Conductive means the surface is resistive. The surface bleeds any charge to ground. If you placed a powered printed circuit board on to the surface, it may fault. You wouldn't normally use this type of mat for your desktop but you could use one for the floor, combined with a conductive shoe strap.

Dissipative means the surface is weakly conductive but there is a more conductive surface underneath. The surface still bleeds the charge to ground but more slowly. This is the type you want on your desktop as you can place powered printed circuits directly onto the surface.

[bsahdy]

what_nz  thanks!!!

for the carpet floor will the non-conductive material be enough?

regarding the wrist band, is it safe to  buy one off ebay?

[Prime73]

regarding the wrist band, is it safe to  buy one off ebay?

I don't see why not. all it is a piece of wire that connect your hand to a ground. you can even make your own.

[bsahdy]

honestly this is somehing i never understood? to ground something is to attach it to the ground post in you outlet?

[katzohki]

Just get a static wrist strap, that will be the cheapest and biggest difference maker. Get yourself connected to ground and you'll be good. To ground something means to be at the same potential as ground. Technically you could just plug a wire into the ground plug of your outlet, but that's probably not the best way to go about it. When I install static protection stuff, I take the face plate off and connect to the screw that attaches the face plate to the outlet. The box your outlet sits in should always be connected to ground. This info is relevant for the US, at least.

[bsahdy]

sweet! thanks

just wondering is there a way to test with a multimeter if something is grounded? for example if i take a piece of metal that is conductive and connect it to the ground via a wire.

i have seen dave measure the conductivity of his esd mat with a muiltimeter on the ohms range?


thanks

[What_NZ]

what_nz  thanks!!!

for the carpet floor will the non-conductive material be enough?

regarding the wrist band, is it safe to  buy one off ebay?

Honestly don't worry about the carpet. Just be sensible when you are carrying things to and from your workbench. When you arrive at your workbench plug your antistatic strap in first, then sit down. That's if, you even need to I just usually touch the grounded frame of my Soldering Station for a second.

Buy the best one you can afford, it's the old saying "anything is (probably) better than nothing"

[What_NZ]

regarding the wrist band, is it safe to  buy one off ebay?

I don't see why not. all it is a piece of wire that connect your hand to a ground. you can even make your own.

 WARNING - No it is not! and in fact, to make one that way could cause the wearer to be electrocuted.

Sorry I had to make that clear.
All antistatic wrist straps will have a high resistance to ground usually 1M OHM or more. This is to limit the current following through the body to a "safe" level in case the wearer comes into contact with a high voltage. Of course the caveat here is, What is high voltage? Know the equipment you are working on and calculate the risk factor. Ask the question  "What will happen to me if I touch a high voltage while wearing an antistatic wrist strap"

[Mr.B]

Before you rush out and buy an antistatic strap...
Do you know anyone in the computer installation and/or servicing industry?
A couple of years ago we did a major infrastructure refresh.
Part of the purchase was a number of EMC Clarion AX4 controllers and 8 disk shelves.
Every unit came with an antistatic strap in the box. We have 10 thrown in a drawer in the server room.
We wont be the only people like this.
Ask around...

[What_NZ]

honestly this is somehing i never understood? to ground something is to attach it to the ground post in you outlet?

If the house/building/dwelling you are in, has been Electrically checked and certified then the simple answer is "Yes"
I don't know if it is the same in the USA as NZ (terminology maybe different) but you can get an Electrician or Electrical Inspector to test your house/building/dwelling. They will test the connection to the Ground Spike (yes it is actually a metal spike driven into the dirt outside) and the electrical safety of all wall plugs (circuits) and will advise if anything is unsafe. If they find anything unsafe or not to Regulation it will be mandatory to have it fixed. Well that was the long answer and probably not necessary unless you have concerns about the state of the wiring.

[What_NZ]

If you can get a couple for free, all the better. Why not ask around as  Mr.B suggested.

If you can, I would suggest to get one with a size adjustable strap, as they will stretch over time and having it adjustable is an advantage. Although if it has stretched so much it maybe time just to replace it. Over time the surface on the inside fills up with dirt and body oil which reduces the effectiveness of the strap.

[SeanB]

Carpet is easy to make less static generative using liquid fabric softener diluted with water and sprayed over it, then left to dry. This leaves a thin static dissipative layer that will wear off every few months, but will reduce static build up. Works on the plastic table too wiping with a cloth dipped in the mix, do top and bottom of the table.

[What_NZ]

Carpet is easy to make less static generative using liquid fabric softener diluted with water and sprayed over it, then left to dry. This leaves a thin static dissipative layer that will wear off every few months, but will reduce static build up. Works on the plastic table too wiping with a cloth dipped in the mix, do top and bottom of the table.

I've never tried this myself. Another advantage I could see, depending on the product selected is a nice residual fragrance 

[SeanB]

Used here by the carpet cleaning firms as a cheap method to dissipate static. They charge a lot for the liquid, but it comes in a bottle marked Sta Soft. Generally lavender flavour, as that is the biggest seller.

[XOIIO]

regarding the wrist band, is it safe to  buy one off ebay?

I don't see why not. all it is a piece of wire that connect your hand to a ground. you can even make your own.

 WARNING - No it is not! and in fact, to make one that way could cause the wearer to be electrocuted.

Sorry I had to make that clear.
All antistatic wrist straps will have a high resistance to ground usually 1M OHM or more. This is to limit the current following through the body to a "safe" level in case the wearer comes into contact with a high voltage. Of course the caveat here is, What is high voltage? Know the equipment you are working on and calculate the risk factor. Ask the question  "What will happen to me if I touch a high voltage while wearing an antistatic wrist strap"

So, I'm curious, if you were in a pinch, had some wire and a 1M ohm resistor, would that work adequately as a temporary solution?

[What_NZ]

regarding the wrist band, is it safe to  buy one off ebay?

I don't see why not. all it is a piece of wire that connect your hand to a ground. you can even make your own.

 WARNING - No it is not! and in fact, to make one that way could cause the wearer to be electrocuted.

Sorry I had to make that clear.
All antistatic wrist straps will have a high resistance to ground usually 1M OHM or more. This is to limit the current following through the body to a "safe" level in case the wearer comes into contact with a high voltage. Of course the caveat here is, What is high voltage? Know the equipment you are working on and calculate the risk factor. Ask the question  "What will happen to me if I touch a high voltage while wearing an antistatic wrist strap"

So, I'm curious, if you were in a pinch, had some wire and a 1M ohm resistor, would that work adequately as a temporary solution?

I'm going to assume I must use one i.e I can't just touch something grounded every now and then and I'm not working on or near anything with lethal voltages.

Under those conditions I would be happy to make up such a device. e.g insulated grounding wire. 1M resistor clipped to metal watch strap or similar.

[bsahdy]

hey guys

is it true that wearing rubber shoe stops you from picking up static charges?