Building an ESD Ground Point, Looking For Feedback

[Senpai]

I'd like to build a new grounding point for my ESD band. So far I've been using an old computer power supply plugged in to a switched off power strip, hooking the ESD clip to the metal case of the PSU. This setup is a big ugly bodge so I'd like to build a smaller ugly bodge to replace it.

I have done some research and I think I've got this schematic right. But I'm told those unhappy looking plugs on the wall like to kill people who poke things in 'em, so I'd appreciate some input on this.

Schematic is attached. Switch is two prong, like these but without the LED: http://www.austinamusements.com.au/images/source/30-1-13/IMG_3232.jpg

I've used multiple 1M ohm resistors in this design in case one shorts out for whatever reason. I'm hoping this will still work?

[MK14]

I'd suggest you buy a proper, quality, well known branded one.

Would you consider making a parachute, out of old clothes and stuff. When you have little/no experience making parachutes ?

Would you jump out with it being your only parachute (no safety second one), from 20,000 feet ?

Safety related items, are best bought (quality/branded ones).

[Senpai]

I'd suggest you buy a proper, quality, well known branded one.

Would you consider making a parachute, out of old clothes and stuff. When you have little/no experience making parachutes ?

Would you jump out with it being your only parachute (no safety second one), from 20,000 feet ?

Safety related items, are best bought (quality/branded ones).

If you can find one with an AU plug I'm all ears. I can't find them anywhere.

Well I found one for $200 and $140 postage. $340 seems a bit much for what amounts to wire and a resistor in most cases though.

[MK14]

I'd suggest you buy a proper, quality, well known branded one.

Would you consider making a parachute, out of old clothes and stuff. When you have little/no experience making parachutes ?

Would you jump out with it being your only parachute (no safety second one), from 20,000 feet ?

Safety related items, are best bought (quality/branded ones).

If you can find one with an AU plug I'm all ears. I can't find them anywhere.

Well I found one for $200 and $140 postage. $340 seems a bit much for what amounts to wire and a resistor in most cases though.

http://www.jaycar.com.au/Tools-%26-Soldering/Hand-Tools/Anti-static-Tools/Anti-Static-Wrist-Strap/p/TH1780



As regards AU mains plugs. I will leave that part, to someone who hopefully lives in Australia, and can explain the situation to you.

[elgonzo]

Nah, MK14 is a quite over-dramatizing the dangerous effects of being exposed to the earth contact.

Remember that for many devices with a metal casing, this casing is connected with the earth contact. If it were so incredibly dangerous to touch such a casing while it is being connected to earth, why in gods name would anyone do that? That alone should be sufficient evidence that connecting something simply to earth does not pose a risk to your health...

ESD bands are not about one's personal health/safety, but about the well-being of your electronic projects. Whether you use an expensive off-the-shelf ESD connector terminal or you build one by yourself should not make any practical difference. If you decide to build one by yourself, it is preferable to not use any jelly-bean resistors. Choose resistors which have characteristics appropriate for the task, such as foil resistors. (Read more: http://www.digikey.com/Web%20Export/Supplier%20Content/VishayPrecisionGroup_804/PDF/vishay-tech-resistor-sensitivity-to-esd.pdf)

Of course, if you build one yourself, be very very diligent that your ESD line will not be in danger of getting in contact with mains live or neutral (ensure this for example by removing the respective contact blades from the mains plug you will use).

EDIT: Made my post more coherent...

[Jeroen3]

Replace the terminals in the plug for bare FR4.
I made a terminal like this myself by removing the line an neutral pin entirely. EU plugs can do that, all other plugs can't.
So you'll have to remove the conducting parts for neutral and live.

One of those yellow plug-in ESD points is a specialty item only to be bought from shops that won't sell to individuals.
Or if you're lucky on eBay, but I couldn't find an EU one. And when I did, it was above hundred euro. Either they use unicorn hair in the resistors or albino plastics. I don't know.

[ChunkyPastaSauce]

If you can, install a GFCI

[Senpai]

Remember that for many devices with a metal casing, this casing is connected with the earth contact. If it were so incredibly dangerous to touch such a casing while it is being connected to earth, why in gods name would anyone do that? That alone should be sufficient evidence that connecting something simply to earth does not pose a risk to your health...

That's a great point.

Think I'll give the vishay ones a miss. The benefit seems to be more about keeping the resistor alive through ESD shock. If my resistor dies from ESD shock then I imagine the resistance will go up rather than down? If that's the case then no problem with me. I don't mind replacing 5 cents worth of resistor.

No problem finding the wrist straps MK14, got plenty of those and already using them. Having a power strip and ATX PSU on the bench just for it is ugly as hell though.

Going to leave the pins in it so it stays firm in the socket, also stops me from plugging it in the wrong way for whatever reason (maybe dark, maybe drunk, who knows!). The plug I have has three separate cavities for each terminal, with only a small hole for wires to come out of each. Just gonna plug the holes with the glue gun so they stay isolated.

If you can, install a GFCI

Not a bad idea. I've got a couple of those lying around, so I'll shove one between my plug and socket.

[Ian.M]

I don't like the idea of having components inside the mains plug.  That's more stuff to come loose and maybe touch the live pin. Bring the earth wire direct to the bonding point project box, anchor it securely and then take it through two 470K resistors (to avoid single point of flashover failure), both securely mounted to solder tags or similar before taking it to the sockets.   Leave out the switch - that's a dumb idea.

[MK14]

I think this is what you want. I managed to find one, hopefully ?

http://www.wagneronline.com.au/esd-earth-plug/soldering/tools-test/acp463as-11314/6832/pd/

[Senpai]

I think this is what you want. I managed to find one, hopefully ?

http://www.wagneronline.com.au/esd-earth-plug/soldering/tools-test/acp463as-11314/6832/pd/

We ship internationally. Once your order is received we will advise shipping cost to you by email.
Your order will be updated with the freight cost.

Appreciate the effort but I've rode that rodeo enough times to know how that'll turn out, especially from Australia.

Looks to just be a wire from the earth to the outside of the plug anyway, so not sure it's really worthwhile.

[Senpai]

Built and installed the thing today, seems to do the trick. Binding posts are the wrong color as that's all I had lying around, but can easily swap them out later. =D

[MK14]

[ChunkyPastaSauce]

I'd never trust myself enough...

[Jeroen3]

Question: Why is there is switch?

[Senpai]

Question: Why is there is switch?

If something happens, the wife won't want to touch the cable, but maybe she'll flick the switch. Have a tonne of them lying around so might as well. Also it's easier to solder from the washer (which is suspended in the air) to something fixed than it is to solder the bendy cable to it.

I'd never trust myself enough...

Would have preferred one of those, but meh. The prongs are completely physically isolated from each other. There's plastic walls between each terminal. Good enough for me.

[apelly]

Clipsal make earth only plugs like the one in the earlier link. I'll have a think about who I bought mine from and post back if I remember.

[jhalar]

I bought my clipsal earth plug from oritech.

http://www.oritech.com.au/463SAS/Clipsal-ESD-Earth-Plug/pd.php

[tggzzz]

Nah, MK14 is a quite over-dramatizing the dangerous effects of being exposed to the earth contact.

Remember that for many devices with a metal casing, this casing is connected with the earth contact. If it were so incredibly dangerous to touch such a casing while it is being connected to earth, why in gods name would anyone do that? That alone should be sufficient evidence that connecting something simply to earth does not pose a risk to your health...

ESD bands are not about one's personal health/safety, but about the well-being of your electronic projects. Whether you use an expensive off-the-shelf ESD connector terminal or you build one by yourself should not make any practical difference. If you decide to build one by yourself, it is preferable to not use any jelly-bean resistors. Choose resistors which have characteristics appropriate for the task, such as foil resistors. (Read more: http://www.digikey.com/Web%20Export/Supplier%20Content/VishayPrecisionGroup_804/PDF/vishay-tech-resistor-sensitivity-to-esd.pdf)

Of course, if you build one yourself, be very very diligent that your ESD line will not be in danger of getting in contact with mains live or neutral (ensure this for example by removing the respective contact blades from the mains plug you will use).

EDIT: Made my post more coherent...

More coherent, maybe: I didn't see the earlier version. But your post is a good example of why nobody in their right mind pays too much attention to pronouncements on forums made by amateurs about safety matters.

Techniques and mechanisms w.r.t. safety have evolved over time based on hard-won experience. Safety mechanisms aren't designed around how they and equipment work, they are based around how they fail - and there are many many many unintuitive failure mechanisms.

Where safety is concerned, follow standard practice because you don't know all the failure mechanisms. Let's make new mistakes.

[Senpai]

Clipsal make earth only plugs like the one in the earlier link. I'll have a think about who I bought mine from and post back if I remember.

Wouldn't worry about it mate. Plug as is now does the job well.

[tggzzz]

Clipsal make earth only plugs like the one in the earlier link. I'll have a think about who I bought mine from and post back if I remember.

Wouldn't worry about it mate. Plug as is now does the job well.

It may do; I won't offer an opinion. But more importantly, how well will it do the job in a years time, and what are the failure mechanisms? Might someone else use it in a few months/years time without verifying that it is still working safely?

Let's make new mistakes. Old mistakes are boring and unlikely to win the Darwin Award

[george graves]

I'd suggest you buy a proper, quality, well known branded one.

Would you consider making a parachute, out of old clothes and stuff. When you have little/no experience making parachutes ?

Would you jump out with it being your only parachute (no safety second one), from 20,000 feet ?

Safety related items, are best bought (quality/branded ones).

Oh my!   

You do realize this is a forum full of DIY types right? And getting shocked with 120/240 isn't that big of a deal.  I've had it happen a dozen times.  And I'mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm fineeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee!  Wait, where's my glasses, oh I'm wearing them.  Oh, where's my eyballs?  Rats! 

[Senpai]

Touching mains for a moment is one thing, it's another when you have a spring corded strap holding it to your skin though lol.

[MK14]

I'd suggest you buy a proper, quality, well known branded one.

Would you consider making a parachute, out of old clothes and stuff. When you have little/no experience making parachutes ?

Would you jump out with it being your only parachute (no safety second one), from 20,000 feet ?

Safety related items, are best bought (quality/branded ones).

Oh my!   

You do realize this is a forum full of DIY types right? And getting shocked with 120/240 isn't that big of a deal.  I've had it happen a dozen times.  And I'mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm fineeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee!  Wait, where's my glasses, oh I'm wearing them.  Oh, where's my eyballs?  Rats!

Until the day you have your LAST electric shock. It is then TOO LATE, to explain to people, why safety is SO, SO important.

If you are electrocuted via something semi-permanently attached to your body. It can make your muscles inoperative, including your heart and/or breathing.

BUT looking on the bright side, at least the wife can switch off (switch provided) the unit, to make it safe, to remove the body.

Safety first!

[tggzzz]

I'd suggest you buy a proper, quality, well known branded one.

Would you consider making a parachute, out of old clothes and stuff. When you have little/no experience making parachutes ?

Would you jump out with it being your only parachute (no safety second one), from 20,000 feet ?

Safety related items, are best bought (quality/branded ones).

Oh my!   

You do realize this is a forum full of DIY types right? And getting shocked with 120/240 isn't that big of a deal.  I've had it happen a dozen times.  And I'mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm fineeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee!  Wait, where's my glasses, oh I'm wearing them.  Oh, where's my eyballs?  Rats!

Until the day you have your LAST electric shock. It is then TOO LATE, to explain to people, why safety is SO, SO important.

If you are electrocuted via something semi-permanently attached to your body. It can make your muscles inoperative, including your heart and/or breathing.

BUT looking on the bright side, at least the wife can switch off (switch provided) the unit, to make it safe, to remove the body.

Safety first!

Yes indeed. The older amongst us have seen corpses and watched people die (and nearly die) in accidents. It concentrates the mind.

When younger I lightly touched live with one hand and neutral with the other. My biceps contracted vigorously, snapping my forearm against my upper arm  - and fortunately breaking the contact. If it hadn't, I couldn't have broken the contact myself.