Good Ground for Anti-Static Wrist Strap

Digger1

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Hi all,

I'm building a computer (my first build) that uses some very expensive (to me) components and am concerned about damaging said components with static discharges.

I live in an extremely dry climate and the ONLY place I can build this computer is in a carpeted room. LOTS of static electricity is generated by even the slightest movements in my house. My wife and I are constantly shocking each other and everything else around here. It sort of sux. I considered going barefoot while building the computer, but it's damned cold in this house.....

Anyway, I was in Scotland a few months back and bought this nice anti-static wrist strap:

Lindy Anti-Static Wrist Strap

Here are the instructions that came with this wrist strap:





As you can see, the manufacturer directs that I attach the grounding strap lead to the computer case, which they direct shall, in turn, via the PSU, be connected to the ground receptacle in the wall socket. However, this won't work for me, since I've not yet installed my PSU into my computer case (I think it is going to be easier to install the mobo with the PSU uninstalled).

I searched around a few places and discovered that many authoritative sources recommend that an anti-static wrist strap's grounding lead be connected, either directly or indirectly, to the ground receptacle in a wall socket.

For instance, PCWorld recommends that the wrist strap be grounded to the wall socket's ground receptacle:

http://www.pcworld.com/article/82184/avoid_static_damage_to_your_pc.html

CompTIA's A+ (Aplus) Certification exams consider the wrist strap being grounded (indirectly) to the wall socket's ground receptacle as the correct choice, if you want to get the correct answer on said exams:

http://www.pccomputernotes.com/esd/esd2.htm

In addition, eHow recommends that same thing (indirect connection):

http://www.ehow.com/how_7566000_use-antistatic-wristbands-mats.html

as does http://www.build-your-own-cheap-computer.com/static-electricity.html

I could go on and on, but that's not the point of this post. Since I am personally more comfortable with being grounded to the Earth, I'm considering connecting the grounding lead of my wrist strap directly to the ground receptacle in my wall outlet. During my research, I found some sources that suggest that I just need to be at the same potential as my computer case (which, according to said sources, can be "standalone" with respect to any other electrical conductors), but the very specific manufacturer instructions for my wrist strap suggest otherwise.

I live in the U.S. and my house's electrical system is grounded in accordance with the 1995 US Electrical Code. Being the skeptic, I tested the wall socket I'd be using with this little Ground Tester I had out in the garage, and all was copasetic.

Does anyone think I'll fry my new computer if I connect the ground lead of my wrist strap directly to the ground receptacle in my wall outlet?

TIA!
 

Digger1

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Hi cute,

Thanks for your constructive advice, but I really would be much more comfortable following the very specific and clear manufacturer's instructions as much as I am able to. I've seen your technique discussed a few times in the course of my research, but I'm going to go with the manufacturer of the wrist strap on this one, I think.

I ended up spending more on my build components than I could afford and now I'm nervous I'll trash something. Lots of static around here.

I considered using one of the anti-static sprays on the carpet, but SWMBO informed me that I'd be sleeping is the street if I sprayed this "nasty crap" (to use her words) on her carpet!
 

Digger1

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:sweat:

It's too late for me now....have pity on my poor soul!

Anyone else have an answer for my question as listed in the OP?:

Does anyone think I'll fry my new computer if I connect the ground lead of my wrist strap directly to the ground receptacle in my wall outlet?
 
G

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Hey Paranoid Builder,


Get a 1 liter spray bottle and add 5 drops of dishwashing detergent, fill it with tap water. Shake well. Spray the area you will be working at, including the carpet. Allow to dry.

Wear your bracelet, grounded to the same place that the boards will be grounded to, (the computer case) so no difference of potential will be available to static-energize the boards. Assemble your computer.

Now is that too hard?

OK, you ask why the soapy water? It prevents static build-up in the first place. Try it on your carpet, see, no more sparks, for days. :)
 
G

Guest

Guest


Yes, you might smoke the whole lot. The ground at your receptacle is also tied to the neutral leg of the power company feed to your house. It is a reference [strike]0[/strike] and establishes the common point for 110 service to allow (2 ) 110V circuits from the 220V center-tapped secondary winding at the supply transformer. If the neutral is not perfectly connected, you can have an "elevated neutral" as a result of another appliance running on the opposite leg of the supply transformer that "lifts" the ground (center-tap) above "ground" as you would think to be always zero, but not in this case. This also allows far more than 110V on the other 110V leg of the transformer as the neutral is no longer "anchored" at zero.

Be smart, do as I said in my first post.
 

Digger1

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Hey Paranoid Builder,


Get a 1 liter spray bottle and add 5 drops of dishwashing detergent, fill it with tap water. Shake well. Spray the area you will be working at, including the carpet. Allow to dry.

Wear your bracelet, grounded to the same place that the boards will be grounded to, (the computer case) so no difference of potential will be available to static-energize the boards. Assemble your computer.

Now is that too hard?

OK, you ask why the soapy water? It prevents static build-up in the first place. Try it on your carpet, see, no more sparks, for days. :)
BoM,

Another interesting technique. Too hard? No. Dangerous? Definitely. You see, I just bounced this idea off of SWMBO and promptly had to dodge an expertly thrown frying pan.

I was then informed that the dishwashing detergent would clean dirt off of the soles of our shoes, thus depositing said dirt onto SWMBO's precious carpet. Now, I've been married, more or less happily, for over 32 years. The understanding is that she will leave my motorcycles alone if I leave her house alone. Works for me.

Thanks for sharing this useful technique, however, I'm sure it will be useful for many others out there!
 

Digger1

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Yes, you might smoke the whole lot. The ground at your receptacle is also tied to the neutral leg of the power company feed to your house. It is a reference [strike]0[/strike] and establishes the common point for 110 service to allow (2 ) 110V circuits from the 220V center-tapped secondary winding at the supply transformer. If the neutral is not perfectly connected, you can have an "elevated neutral" as a result of another appliance running on the opposite leg of the supply transformer that "lifts" the ground (center-tap) above "ground" as you would think to be always zero, but not in this case. This also allows far more than 110V on the other 110V leg of the transformer as the neutral is no longer "anchored" at zero.

Be smart, do as I said in my first post.
BoM,

Good post, very informative.......

I did encounter said information during my research:

http://en.wikipedia.org/wiki/Ground_and_neutral

In particular, the following paragraph caught my attention during the initial read:


Fixed appliances on three-wire circuits

In North America, the cases of some ovens and clothes dryers were grounded through their neutral wires as a measure to conserve copper during the Second World War. This practice was removed from the NEC in the 1996 edition, but existing installations may still allow the case of such appliances to be connected to the neutral conductor for grounding. Note that the NEC may be amended by local regulations in each state and city. This practice arose from the three wire system used to supply both 120 volt and 240 volt loads. Because ovens and dryers have components that use both 120 and 240 volts there is often some current on the neutral wire. This differs from the protective grounding wire, which only carries current under fault conditions. Using the neutral conductor for grounding the equipment enclosure was considered safe since the devices were permanently wired to the supply and so the neutral was unlikely to be broken without also breaking both supply conductors. Also, the unbalanced current due to lamps and small motors in the appliance was small compared to the rating of the conductors and therefore unlikely to cause a large voltage drop in the neutral conductor.


Apparently, the situation you posit is a recognized hazard that is considered so remote as to be acceptable in currently standing "old construction."

In any event, as I stated in the OP, I tested the ground circuit of my house with the above-mentioned tester. I also tested the voltage between the neutral circuit to the ground circuit with a VOM and found it to be 0 VAC.

I'm pretty certain that the ground circuit in my house is safe and stable. If it wasn't, I'd face a similar risk on everything in the house that has a case ground.

As for the dish washing detergent solution advice rendered in your first post, I have since explained why that technique is a non-starter for me.

Thanks for your time and expertise!
 
Mount the PSU, turn the PSU switch off and plug it in....the case is now grounded to the wall outlet and when you connect your stap to the case so are you.

Note....I have been building PC's since 1986 and never used a wrist strap.

Take off ya shoes and no worries about carpets :)

Be aware that the manufacturer is trying to sell a product and therefore has an interest in you having an elevated concern in this regard.
 

etk

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Everything you buy will be diode protected. Where these components are made, gloves will probably not even be worn before they throw it into the antistatic bags. It's consumer electronics...you don't need an ESD bracelet.
 

Digger1

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Jack,

I appreciate your constructive input....my comments in bold italics.




Thank your for your expert advice!
 

Digger1

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Don't think it hasn't crossed my mind (vbg)!
 

Digger1

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People speak of static too much as it's not a big thing tbh.
I have never worried about static and i have built many machines.
384,

Thank you for your post (and, your service).

Two things:

1. I've met and worked with a lot of paratroopers over the years, and, to put it politely, Y'ALL ARE CRAZY!

2. I presume you are still living in the lush, green, relatively moist UK. As such, static may not be a big problem for you. Where I live, static electricity is ubiquitous, severe, and potentially fatal to my expensive computer components. I'd just feel a lot more comfortable adhering to the spirit of the detailed and extensive instructions that were enclosed with my anti-static wrist band.

I purchased said wrist band in Scotland, BTW. We were up there (Aberdeen and Wick) working with school kids. I always remind them to work hard in school, as the world could use a few more brilliant Scottish engineers! They are some of the best kids in the world, IMHO, in many ways putting American kids to shame (and, believe me, it hurts me bad to say that)!
 

Digger1

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et,

Thanks for your constructive and informative answer.

Like I've said before, I would just feel a lot more comfortable complying with the spirit of the detailed and specific manufacturer instructions that came with my wrist strap. I'm anal in lots of ways.....which, in my case, is a good thing, since I should have been killed many times over by now in my life. My anal approach to many things is the only reason I'm still here.......I'm absolutely convinced of that!

I want to use the wrist strap, and I want to ground it using the safest and most conservative method that is reasonably available to me.


I've let the discussion drift a bit.......let's please get BTT!

The question I asked 16 posts ago in this thread still stands: Does anyone think I'll fry my new computer (or, myself) if I connect the ground lead of my wrist strap directly to the ground receptacle in my wall outlet?

 
G

Guest

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Baaa Humbug. 5 drops of liquid soap to a liter of water won't clean anything. I also said to let it dry. The molecular level residue prevents static that's all. Do it when she's not looking.
 

Digger1

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I'm not disputing the fact that there is an overwhelming chance that you are correct.

However, the fact remains that I'd still feel a lot more comfortable complying with the instructions that came with my wrist strap.

It's a personal problem.
 

Digger1

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Yes i will agree we are a crazy bunch :ange:. As for scottish engineers or the british army in general (Discapline) ;)
However this static thing is really not as bad as you may think.
Chill out pal ;)

384,

I'm not disputing the fact that there is an overwhelming chance that you are correct.

However, the fact remains that I'd still feel a lot more comfortable complying with the instructions that came with my wrist strap.

I'm just a stubborn old fighter pilot, probably exposed to a little too much AAA (I used to fly through the explosions on purpose - you know the type). It's a personal problem (vbg)!
 

Digger1

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Baaa Humbug. 5 drops of liquid soap to a liter of water won't clean anything. I also said to let it dry. The molecular level residue prevents static that's all. Do it when she's not looking.
BoM,

You don't understand, my friend. I fear that woman more than I used to fear SA-10's. We're talking death, here, especially since she has now been alerted to this situation....... (vbg)
 
Well here's another thing for you to be paranoid about .

By earthing yourself to the planet you do not reduce electrical potential between yourself and the case ........but you do provide an excellent path for static to flow .

You are INCREASING the change of damaging components .

And you are still an idiot
 

Digger1

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I've lost control of this thread......back in my fighter pilot days, I'd say that I'd lost control of my four-ship.

Over 170 views on the world's best and most authoritative computer hardware forum and I have not been able to get an answer to my question. My fault, of course, for letting the discussion stray.

It's time to re-frame the constraints of the debate.

Let's just say that, for whatever reason, I wanted to ground my anti-static wrist strap to the grounding circuit in my house.

Assumptions:

1. Said grounding circuit is in compliance with the latest United States Electrical Codes.

2. Said grounding circuit has passed a comprehensive inspection that was conducted by a fully licensed, certified, and bonded Master Electrician, who is a card-carrying member of the International Brotherhood of Electrical Workers, and who specializes in residential inspections.


Now, the question is:

Does anyone think I'll fry my new computer (or myself) if I connect the ground lead of my wrist strap directly to the ground receptacle in my wall outlet?


Please let us keep the discussion to a tight, laser-like focus.

TIA!
 

etk

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Static wristbands have high resistance to prevent this from happening. As long as the wrist band tests good (1 megohm for 250V, 500k for 120 iirc) you can plug it into the ground plug and grab a live wire safely with your other hand, if you so choose.

OP: If you want to take safety to an extreme here, check the strap resistance first, then plug it into the ground outlet. Anywhere from 500kish to 100 Meg+ is fine
 

Digger1

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Now, that's not very nice..... (vbg)

Oddly enough, however, your contention goes against information found in the following very credible sources:


For instance, PCWorld recommends that the wrist strap be grounded to the wall socket's ground receptacle:

http://www.pcworld.com/article/82184/avoid_static_damage_to_your_pc.html

CompTIA's A+ (Aplus) Certification exams consider the wrist strap being grounded (indirectly) to the wall socket's ground receptacle as the correct choice, if you want to get the correct answer on said exams:

http://www.pccomputernotes.com/esd/esd2.htm

In addition, eHow recommends that same thing (indirect connection):

http://www.ehow.com/how_7566000_use-antistatic-wristbands-mats.html

as does http://www.build-your-own-cheap-computer.com/static-electricity.html

In addition, your contention strongly contradicts the specific instructions that came with my anti-static wrist band:






I could add scads more credible references, but I think my point has been made.

In your defense, however, perhaps you are referring to an electrical supply system that is non-compliant with U.S. Electrical Code. In that case, I plead ignorance....I've not researched those.
 

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