Correct ESD Desktop mat installation - Page 1
Forum section: electronics / beginners

author: Spekkio
author_rank: Regular Contributor
timestamp: August 09, 2015, 11:17:49 am
content: Hi!I recently bought a ESD mat for my desktop.But I am not quite 100% sure that I have it installed in a good way.I've been looking around on the forum and googling, but I can't find a good answer for me.Because there is no ground connection in my wall outlets in this old house.Most of the stuff I've found online require this.From what I have learnt about electricity over the years, is that ground is called "ground" because it is simply a connection to ground. A very large object that most probably have as many negative charges as it has positive charges, resulting in a 0 voltage potential. So that static electric charges will get sucked down into ground before zapping any other sensitive electronics.In new houses they install some kind of protection device which I know nothing about, Residual-current device?A simple online search would probably answer that for me.Since there are no ground connections in my wall outlets there is probably no such thing here as a Residual-current device?This is my current set-up:I have a power strip with ground connections in it. To one of these ground pins I have connected my ESD mat with a 1MOhm resistor in between. And my equipment, oscilloscopes, bench multimeter and my computer etc is connected to this power strip.But I just have this bad feeling that it is not a good at all. Should I connect the ground from my power strip to my radiator piping, which most probably is connected to ground?What if there is a thunderstorm, would ground have higher/lower potential than usual?Would a connection like that even cause things to get catastrophic in such case?Or would it even matter much, would the whole house have the same electric charge anyway?Or is my ESD mat just not even necessary in my home lab on this quiet large wooden desktop that I have?I kind of feel a little bit stupid asking these questions, I should know these thingsBut I need to, and want to get things in good order and a better understanding on this.

author: German_EE
author_rank: Super Contributor
timestamp: August 09, 2015, 11:38:29 am
content: 1) First suggestion, speak to an electrician as I have no idea of the wiring codes in Sweden.2) Wiring your anti-static mat to a radiator will probably be OK as your central heating system will use copper piping. Please check that your incoming water pipe is connected to mains earth.3) Running a workbench off mains sockets that are not grounded is a very bad idea as the chassis of anything you are working on may become live, please see (1) about speaking to an electrician.

author: rs20
author_rank: Super Contributor
timestamp: August 09, 2015, 12:01:42 pm
content: Quote from: Spekkio on August 09, 2015, 11:17:49 amThis is an oft-repeated idea, but I'm pretty sure it's bogus. There's nothing magical about the Earth and its hugeness that's really relevant, except for that fact that, for example, people gardening using electric tools are in contact with the Earth with their feet, which is why RCDs are useful. Mains electricity supplies are earth-referenced, and people are walking around on the Earth an awful lot, and therein lies the opportunity for a complete circuit to be formed that includes a human being. This is where Earth becomes a useful concept (because the earth-human interface can become part of acomplete circuit, which is not healthy).Now when it comes to you in your isolated room, none of this is particularly relevant. Your equipment, oscilloscopes, bench multimeter and computer all have the same local ground (where I define "local ground" to mean not necessarily connected to Earth), and if your work mat and you body are connected to the same local ground, then your equipment and you can't have different static potentials, there can be no static voltage between anything, and no static discharge can occur.The key point is: like any other voltage, static charge isrelative. Connecting yourself to Earth could be the worst thing imaginable if your device has 20kV of static charge on it, because now you have 20kV of charge relative to the device, so you can ESD it. If youbothhave 20kV of static charge (with respect to the Earth), then you're both at the same potential and the device is safe from damage. Voltages arealways relative.I concur with German_EE though that running a unEarthed workbench is very dangerous --not at allbecause ofstaticelectricity, but because of the risk ofmains electricityelectrocution since an RCD can't possibly work in your situation, nor can fuses work in the case of line-to-case shorts. Indeed, if your local ground is floating, a line-to-case short in any one device will make all of your devices' cases live, which would be no good if you leaned on the radiator at the same time as probing a circuit!

author: Spekkio
author_rank: Regular Contributor
timestamp: August 09, 2015, 01:06:46 pm
content: Thanks for the answers so farI'll do some more investigation.Just a quick thought, would it do alot better to get a power strip with surge protection and replacable fuse instead of this cheap IKEA crap.But then there are like.. too many options...Premium-Protect-Line Surge ProtectionOffice-Line Surge ProtectionPremium-Line Surge ProtectionPrimera-Tec Surge ProtectionSecure-Tec Surge Protectionhugo! Surge ProtectionSuper-Solid Surge ProtectionEco-Line Surge ProtectionPower Manager Surge ProtectionAdapter Surge ProtectionI also found one power strip with RCD (edit) fromwww.brennenstuhl.com, it seems to be built for outside use on this swedish sitehttp://www.jula.se/catalog/el-och-belysning/elinstallation/kabelforlangare-forgrenare/grenuttag/grenuttag-med-jordfelsbrytare-404033/trying to find the same product onwww.brennenstuhl.com, have not yet found it.

author: rs20
author_rank: Super Contributor
timestamp: August 09, 2015, 01:24:12 pm
content: Different surge protection levels refer to the amount of energy in asurgethat the device can shunt away safely. A surge is an overvoltage event on the mains electricity, which is a different thing to either static electricity, or electrocution prevention.Quote from: Spekkio on August 09, 2015, 01:06:46 pmI don't know what you mean by "RDS"; if you mean RCD (i.e. "jordfelsbrytare"), then that requires a third earth lead to be of any use within an otherwise isolated room. I suppose it might theoretically protect you from touching live and the radiator simultaneously, but it is no substitute for proper earthing.

author: Spekkio
author_rank: Regular Contributor
timestamp: August 09, 2015, 02:33:02 pm
content: Quote from: rs20 on August 09, 2015, 01:24:12 pmYes, I understand.I thought surge protection in the power strip might be an extra added protection to have anyway.I'm reading a about RCD online now.It is detects a change in the sum of live+neutral, so that if it is too large, an automatic switch will open to shut down the power.I'm reading that most RCD's will detect a 30mA current.From what I understand, the signal on live are out of phase of neutral, so the sum of the two is zero in a normal case?I was thinking of connecting the ground from my power strip to the radiator, like I described in my first post.That was my first intention.Or thought that it was the good thing to do.But what If I used an RCD, to connect it's ground connection to the radiator, I thought that maybe could help in either case, if the radiator is or is not connected to mains earth.I've been looking around in the house, some of the sockets around the house does have ground connections, others don't.For example in the kitchen there are ground connections in the outlets.Oh... these old early 20th century houses *sigh* :/So If the radiator pipes are connected to mains earth, I have no idea...I think I'll contact the landlord first, he might know. I don't want to do anything stupid hereAnd also go back to what German_EE said first, to contact an electricianMight be the best idea for meI just hope that my current installation is not too dangerous, or that it actually has some functionality and is not completely useless.There is no risk that I will touch a radiator and my desktop at the same time anyway.Quote from: rs20 on August 09, 2015, 01:24:12 pmYes, of-course, just a typo. Fixed it.

author: Spekkio
author_rank: Regular Contributor
timestamp: August 09, 2015, 02:49:44 pm
content: btw, just something popped into my mind. I measured the VAC between the radiator and my desktop ESD mat.And it is 73 VAC, not a good connection there maybe.Directly from my floating ground pin on the power strip to the radiator is 113 VACAh, I don't know what that means right now. That is half of 220VAC, I am getting tired, maybe it is normal and means nothing.

author: lapm
author_rank: Frequent Contributor
timestamp: August 10, 2015, 12:35:55 am
content: I will recommend talking to qualified electrician about this. Might help insurance issues later if you manage to brake something expensive you cant fix...

author: Spekkio
author_rank: Regular Contributor
timestamp: August 10, 2015, 06:27:50 pm
content: Maybe I am going a little bit to far surrounding my ESD desktop mat when mixing in residual current devices etc..I asked at work, and they said that just having my ESD mat connected to the power strip with my equipment and computer is just perfectly OK with ungrounded power outlets. There is not much to worry about. It works like it should. I just don't want it to be useless.But I am just that kind of person , if I don't understand something well enough, it is going to bug me and I can't get it out of my mind, and I might go a little bit too far in my analysis surrounding it all. Because I also want things to be perfect.I bought a cheap RCD today that I am going to take apart and take a look inside, I am a bit curious about that. Since I know practically nothing about that. And that is fun. I love learning new things.There is really no worry that I will touch my radiator while sitting at my workbench. It is far away. And in any other case, the wiring in my house is like this everywhere, there are no grounded outlets (except in the kitchen). There is no RCD from what I know, I can't find such a device anywhere. I expected it to be near my fusebox maybe, need to ask my landlord about that... But people say, that ungrounded poweroutlets and no RCD's is a common reason old houses like this burn down, bad and old electrical wiring. Putting in ground in all my poweroutlets in this old house is just too much work. So the problem is in every power outlet here. My TV and my stereo and everywhere else.Skickat från min GT-I9305N via Tapatalk

author: German_EE
author_rank: Super Contributor
timestamp: August 10, 2015, 07:42:59 pm
content: OK, let me have another go.If you plug in a power strip to an ungrounded outlet the earth connections on the power strip will not be connected to anything. If you then connect your anti-static mat to the power strip this will also not be earthed.An RCD works by comparing the currents in the live and neutral lines. If you connect a load (such as a light bulb) to the mains supply then equal currents will flow through live and neutral and everything is safe. Assume now that you have a fault and the live connection contacts the GROUNDED FRAME of your lamp. More current will flow through the live lead than the neutral and the RCD will trip, cutting off the supply. Some RCD devices also measure the current in the ground lead but in any event an RCD needs a three pole connection (live, neutral, earth) to correctly function.If you are working on a device on your ungrounded workbench and the chassis is live then YOU will provide a path to ground if you touch the equipment. This could just provide a slight tingle if you are wearing rubber soled shoes or, if the current is higher, it may be enough to kill you.Please speak to an electrician.

author: rs20
author_rank: Super Contributor
timestamp: August 11, 2015, 10:21:04 am
content: Quote from: datumplane on August 11, 2015, 09:28:40 amCitation needed -- as I suggested in my earlier message; if the wriststrap is connect to the mat, and the oscilloscope, and the power supply, and all the components in antistatic bags sitting on the antistatic mat, etc, etc -- how can a significant static voltage differencebetweenany of those items be sustained? And if none of those things can be at a high voltage with respect to each other, how can an ESD event occur? What's so magical and special about the Earth?

author: German_EE
author_rank: Super Contributor
timestamp: August 11, 2015, 10:35:49 am
content: Mains earth to central heating radiator, 0,3 ohmsMains earth to kitchen water pipe, 0,2 ohmsApartment RCD last tested January 3 2015Workbench RCD tested this morning.I don't know where the central heating pipes are grounded as this is a 'whole house' system that supplies 32 apartments but our incoming water and mains electricity enter our apartment at the same point with a pipe ground strap about 7cm long. There are ground straps before and after the water meter (just in case the meter contains plastic parts) and it's obvious that the electricians here are not messing around as our apartment supply is three-phase 60A per phase.

author: Spekkio
author_rank: Regular Contributor
timestamp: August 11, 2015, 11:06:30 am
content: I don't build PC's often. But I hear questions sometimes on how to connect your wriststrap when assembling PC components.-"Just connect the wristrap to the PC chassis"Is the only thing I've heard. Wouldn't that also be just a floating wireless wriststrap I am starting to understand a little bit more in the line of what rs20 is saying. The entire desktop might be floating with some charge, the place where I have defined as ground, the ground connections might have a large charge on it, like an offset voltage. So I have this reference on my workbench. But the danger could be if the radiator might have a much lower potential compared ro my floating ground in my powerstrip and also in my esd mat and equipment. That could lead to a catastrophic result if I would touch the radiator while touching my desktop (Did I get that right now)But as long as I am working isolated on my desktop. My esd mat works the way it is intented. It is not until some somerhing with a much higher or lower charge walks in and ruin things.I would like to get things in good order, maybe I've already said it. But I mean. Would it even be better to just disconnect the esd mat. *meh* it is just pointless now..or.. not.. I would love to have a good and safe workplace at home.I know it is probably outside of the esd discussion that I would want to get a better understanding of. But. I just bought a cheap RCD that I am going to tear apart and look whats inside.Skickat från min GT-I9305N via Tapatalk

author: Zeyneb
author_rank: Regular Contributor
timestamp: August 11, 2015, 06:13:36 pm
content: Hi,Yes I do recommend connecting all of your equipment to protective earth. I don't take any responsibility for what you should do to get that. But basically you need to search for the green-yellow wire behind other outlets or ceiling boxes (I'm not familiar with the actual term). From there you need to run all the three electrical wires (brown - live, blue - neutral and green-yellow - protective earth) with the proper diameter to the location where that old socket was. And replace that with a socket that has protective earth. Do all of this in a way according to your national electrical standards. As you're familiar with electronics please just use the components for regular AC mains electrical work.I really hope for you your landlord is willing to corporate. If you might think he/she is just interested in your rent. Then I would personally just implement it myself without his/her knowledge.Good luck!Zeyneb

author: Spekkio
author_rank: Regular Contributor
timestamp: August 11, 2015, 09:49:43 pm
content: Quote from: Zeyneb on August 11, 2015, 06:13:36 pmHmm, yes I know that green-yellow is ground. But this is a very old house. Probably built in the early 20th century. I don't know much about proper rules about grounding wall sockets back in 1900-1940.Most.. well almost every old house I've seen in my life doesn't have ground pins in the wall outlets. My fathers house was built in 1975, no ground pins in those wall outlets either.I have not checked every outlet in the house. But the ones that I have checked only has live and neutral wires, except in the kitchen. Obviously. It would be strange if there would be a loose ground cable inside that is not used.I have checked behind the outlets in the kitchen. And they have a green-yellow cable. And and ground pins on the outlets. But only in the kitchen. The explanation might be that this kitchen is quite new compared to the house itself. The kitchen on the top floor here was built in here when they decided to make the top floor on this old house an apartment that I currently rent.I think installing proper grounding everywhere in this house is quite alot of work.I mean, if my esd mat is so dangerous? What about every single powerstrip that lays around here. Some of them right under the radiators.So, what can I do in my current situation... from what I understand so far. My desktop ESD protection isn't really useless, it still works the way it should?Btw. The RCD thing that I bought. When I connected it to one of the outlets in the kitchen. It didn't work....? Shouldn't it open if if the wall outlet was properly grounded?I haven't dissasemled it yet, it had some strange three sided screws.Skickat från min GT-I9305N via Tapatalk

author: helius
author_rank: Super Contributor
timestamp: August 11, 2015, 10:55:31 pm
content: What type of earthing system is used in your area?https://en.wikipedia.org/wiki/Earthing_systemIf you are in an area using the IT-system, RCD does not work. This is because ground fault current cannot trigger the device.

author: rfeecs
author_rank: Frequent Contributor
timestamp: August 11, 2015, 11:44:35 pm
content: Quote from: helius on August 11, 2015, 10:55:31 pmThis doesn't sound right. The RCD (In US we call it GFCI) doesn't detect ground current. It doesn't need a ground connection to work. It is triggered by an imbalance in current between hot and neutral. The idea is that if the hot and neutral currents are not equal and opposite, current must be flowing somewhere else (like through you to ground).In fact, in the US if you have an old house with no ground connection to the outlet, one acceptable method of replacing a two pronged outlet with a three pronged outlet is using a GFCI outlet.

author: helius
author_rank: Super Contributor
timestamp: August 11, 2015, 11:52:38 pm
content: Remember Kirchhoff's circuit laws. For current is flowing "through you to ground", it must be flowing back somewhere else in the circuit from ground to the supply. In the IT-system, that is not possible since the supply is isolated from earth. RCD never triggers because there is no way for the power in the line to become "unbalanced".

author: rfeecs
author_rank: Frequent Contributor
timestamp: August 12, 2015, 12:42:15 am
content: Ahh. I see what you are saying. So in the IT system the supply is isolated from ground. So in that case the RCD serves no purpose. Got it.(edit)Looking back on this thread, three previous posts have said that an RCD will not work without a local ground connection. So to clarify, in a TN system, where the neutral is grounded at the supply, which is the most common situation I think, an RCD will still work even if it is not connected to ground.

author: VK5RC
author_rank: Unknown
timestamp: August 12, 2015, 02:24:05 am
content: The RCD self test (used to see if it is working) usually requires a connected earth line to soak some current away from active or neutral in a fully floating power supply environment.

author: NoItAint
author_rank: Contributor
timestamp: August 12, 2015, 02:39:27 am
content: Around here you can buy copper bonded steel grounding rods. 8ft long.Since it's not used for electrical power ground you only need a light duty wire to it.You call 811 before you drive it home.Don't forget the ESD resistor.

author: rfeecs
author_rank: Frequent Contributor
timestamp: August 12, 2015, 03:03:49 am
content: Quote from: VK5RC on August 12, 2015, 02:24:05 amIt may depend on the unit, but I have some in my house without a connected earth line and the self test still works. As I understand it, the self test button bypasses some current around the sense transformer and this creates an imbalance that trips it.

author: schopi68
author_rank: Regular Contributor
timestamp: August 12, 2015, 10:22:23 am
content: On this site you'll find a lot of information giving ideas about the requirements.http://www.esdjournal.com/techpapr/eosesd/static/sgscw.htmhttp://www.esdjournal.com/techpapr/eosesd/grounds/fsg.htm

author: Spekkio
author_rank: Regular Contributor
timestamp: August 13, 2015, 11:54:23 am
content: Quote from: Zeyneb on August 11, 2015, 06:13:36 pmlol, you don't have to worry about that

author: Spekkio
author_rank: Regular Contributor
timestamp: August 13, 2015, 12:52:58 pm
content: *sigh* I feel that I can't do anything really, it is way too much work is this old house.I'd have to tear down walls and rewire the entire electrical system in the entire house to get properly grounded outlets.I rent this place, I don't think my landlord is interested in installing proper grounding just for my little home lab.The house is just too old. And sometimes I get the feeling from my landlord that he'd rather tear it down if he can't get anyone to rent it.I've heard that the electrical bill for this house it pretty big. And the heating is not very efficient.In the kitchen however, there are grounded outlets.I've checked that they are connected to the sink, wall outlet gound -> sink.But I don't know if they're connected to anywhere else in the house, an RCD or any system like that.I don't think I've got much use of using that ground. I suspect it is only localized to the kitchen sink and maybe other kitchen things.Or maybe that is the best ground connection I have in this house.I'll just have to go with just having my local floating ground like it is now in my power strip, I don't know if there is anything I can do to make it better.The mat is connected via 1MOhm to the power strip with all my equipment, which you can see in the picture from my first post.Which would mean that all of my equipment have the same ground point. So my ESD mat would work as intended, that is what I have learnt so far.I thought the idea of a good grounding point, for example a stake into earth, was good so that the ESD mat could slowly discharge any static charges.In my current situation, my floating ground is localized only in my power strip.I thought that this ground point could have a charge on it,like an "offset voltage", so it wouldn't discharge static electrical charges sometimes as good as a real grounded system would (and with real, I mean a stake into ground).From people I've been talking to at my job, and other people I have asked. They say my installation is just good enough, no problem with that set-up at all.And there is "nothing magical about ground", there is no need to drive some long stake into ground/earth to get a better ground point?Did I get that right?Is it even worth the effort? Could it even cause more harm than good? Except for destroying my neighbours flower gardenI live on the second floor I guess connecting to the drain pipes in the roof and made sure they're connected to ground.But that would also make a very nice conductor for lightning directly into my expensive equipment, nah. sounds like a bad idea right?I don't really know what is meant by "some chassis can get live", the only way I can think of that happeningis if I was messing around with something while it was plugged into the wall outlet?Which I never ever would do in any case. I have total respect for mains voltage and large capacitors from TV's etc..How can anything get live, without me doing something?Or you mean if I was measuring on, let's say my broken PC Power supply.And for some reason connecting ground probe from example my bench multimeter to a live wire and my positive probe to ground.Hmm, yeah..Thanks for all the information so far.

author: Spekkio
author_rank: Regular Contributor
timestamp: August 13, 2015, 12:57:18 pm
content: I'm still curious to see what is inside my little cheap RCD thing I bought, I need to open it by force with my Dremel I think.

author: helius
author_rank: Super Contributor
timestamp: August 13, 2015, 01:37:35 pm
content: three-winding transformer wired to a latching relay

author: jlmoon
author_rank: Unknown
timestamp: August 13, 2015, 01:41:06 pm
content: Quote from: Spekkio on August 11, 2015, 11:06:30 amDepends on what you're doing with the PC. Installing PC cards , memory and other items. Think about it this way, if your ground strap is tied to the pc chassis, is the PC ground via plugged into what ground level? what is the potential of the surface the memory strip, pc card? Think of the potential difference between true ground (Earth) , you and what the cards or devices are sitting at. This is where the damage can occur. PE is only assumed unless you have run various test and such.

author: Spekkio
author_rank: Regular Contributor
timestamp: August 13, 2015, 01:51:29 pm
content: Quote from: helius on August 13, 2015, 01:37:35 pmI'll look into this.I've been thinking that there must be something that I can do locally at my workbench to make it a safe workbench for electronics tinkering.

author: Spekkio
author_rank: Regular Contributor
timestamp: August 13, 2015, 02:29:00 pm
content: Quote from: jlmoon on August 13, 2015, 01:41:06 pmWell, yeah. HmmI think I understand potential differences well enough, I have a bachelors degree in electronics engineering anyway. Altough that doesn't always mean anything, lolMaybe I'm the worst electronics engineer ever.Sometimes I feel so stupid that I can't get a good understanding of the most simple stuff....But, where was I.Charges are invisible, so you never really know at what potential you are at if you have a wrist strap connected to a chassis that is not connected to anything else.And if the floor you're standing at doesn't dissipate your static charge.I have always had in mind, or had the understanding that a good connection to earth/ground (physical rod stuck into the earth) then you could safely say that my potential, or static charge has dissipated and is close to zero.If you have your components and things you're working on at an ESD mat, an isolated upper surface that dissipates static charges to the conductive plane underneath and then through a 1MOhm resistor down to ground. And a wrist strap with an 1MOhm resistor would slowly dissipate your static charge down to ground if it was either positive or negative. Working with PC components on such a workbench would be much better, from my point of view.But if there is no real connection to earth/ground (rod into earth) on your ESD mat and wrist band, like I have now with my isolated local ground point in my power strip, how can I be sure static charges are being dissipated? They're not, right?Maybe it doesn't matter. If the ESD mat, my wrist band and my PC chassis (for example) all are connected to the same ground point. It doesn't matter if it has a 20kV charge on it. There is no way, I can touch something that would cause a discharge into some sensitive circuit because they all have the same charge.Until I move away from of my workbench and touch something else that is not connected to my isolated workbench grounding.But I would like to have the best set-up I possibly can, in this bad situation I'm currently in.

author: jlmoon
author_rank: Unknown
timestamp: August 13, 2015, 03:12:57 pm
content: Maybe it doesn't matter. If the ESD mat, my wrist band and my PC chassis (for example) all are connected to the same ground point. It doesn't matter if it has a 20kV charge on it. There is no way, I can touch something that would cause a discharge into some sensitive circuit because they all have the same charge.Until I move away from of my workbench and touch something else that is not connected to my isolated workbench grounding.But I would like to have the best set-up I possibly can, in this bad situation I'm currently in.I agree but.... that 20kV charge will have the desire to neutralize one way or another. Which means it could bleed through those parts you picked up off that ESD mat sitting at 20kV while you forgot to put that wrist strap on.Just as a matter of approaching correctness, I would suggest to simply drive a copper clad 8 - 10' rod near as you can to that workbench and run a #6 wire to your common bench ground point. Calling this your common PE ground node. Be sure to use CAD welded lugs if you can and ensure the power ground system is common to this as well. The best solution would be to find or install that ground rod at the base of power entrance and tie back to that point with that #6 copper wire if you can.

author: Spekkio
author_rank: Regular Contributor
timestamp: August 13, 2015, 07:36:42 pm
content: I don't know if this has anything to do with my ESD setupBut I just tore one of these RCDs apart just to see what is inside, and it seems to be a very interesting device to analyzehttp://spekkio.blogspot.se/2015/08/tearing-apart-residual-current-device.htmlI was expecting some connections to the ground pins, but there is none? Or there is something hidden inside that plastic between live and neutral that I cannot see.The thing didn't work in my kitchen. The relay was open.But when I put it in my non grounded outlet I could hear the relays clicking inside atleast.

author: rs20
author_rank: Super Contributor
timestamp: August 14, 2015, 09:43:29 am
content: Quote from: Spekkio on August 13, 2015, 07:36:42 pmThe RCD circuitry doesn't need the ground pins, it measures animbalancebetween the live and neutral. After all, fault current may go through the earth wire or through a human being, it's a fault either way. The imbalance is tested for by passing both live and neutral through a current transformer; under normal operation, they will cancel out perfectly. Seethis link, number 6 is the current transformer, and you can see the thick live and neutral wires passing through it.

author: McBryce
author_rank: Super Contributor
timestamp: August 14, 2015, 10:06:16 am
content: If you have central heating in your house you just need to take the Earth from the nearest radiator to your workbench. It will have to be earthed.McBryce.

author: Spekkio
author_rank: Regular Contributor
timestamp: August 15, 2015, 01:05:07 pm
content: Quote from: McBryce on August 14, 2015, 10:06:16 amThat was what I was thinking of doing in the first place. I suppose, if I do that, it should not be a direct connection from my power strip ground pins to the radiator?I need to put some large resistor in-between? Like 1MOhm, maybe even 10MOhm?But there there has been comments here making it sound like it is a bad idea. Like, I should first make sure the radiator is connected to mains earth...but there is no mains earth/ground wiring in this house... except in the kitchen. And I need to get the thumb out and ask my landlord how things are set up in this old house... Where is mains earth wiring really located here in this house. I don't want to drag a cable out to my kitchen sink.Maybe I could check if the kitchen sink is connected to my radiator pipes? I just need a long cable.Some say, a large mass of copper (or other good conductor material) would do just fine as a decent ground point.It sounds like an easy and good solution, if it really works as intended. Not only in theory I mean, but actually works very well in reality.It's not the first time I hear about that. I think my understanding of this comes from my basic knowledge in physics that I might have read it in a physics book or got taught in school.Wiring something out of the window down to ground from the second floor where I live just feels awkward.I don't want to build a nice lightning rod connected into my expensive equipment.I can measure from my floating ground in my power strip to the radiator a 113VAC, what that does that mean really?Reminds me alot of when I got floating Vcc pins on circuit boards, and I measure 1.65V on them with reference to ground (or what is supposed to be ground).When they're supposed to be 3.3V, but the connection is broken somewhere, it is an open circuit.I don't have a very good understanding of what that means, why it gets that way. Why half the voltage?Also, a little bit outside of the ESD question, but. For safety of not getting electrocuted, can I actually have good use of an RCD unit in my wall outlets for my workbench equipment, or will it only cause problems?I installed power strips with surge protection (Also not really ESD related), but then read in the manual that they're useless in ungrounded wall outlets.But are they useless if I have an RCD before it?I wish I just had more time and motivation to work on these things and thoughts and stupid ideas I got a little bit more.Maybe I could have gotten things in good order already now.But I've got so much to do surrounding my bad health situation also. And having problems both physically and mentally.which you can read about here if you want.https://www.eevblog.com/forum/chat/hello-from-a-sad-and-sick-engineer/Anyway, I've gotten some really good information from everyone here! I thank you so much!I really like the EEVBLOG forum.I just need to sort all of this information out, because all of it feels a little bit tangled up in my head right nowAnd also, I am not certain at all about my radiators here, they're connected down in the basement to some heating device and pump I assume.They're old, some pipes are rusty. Some radiators leak out water. The system needs to get a refill with water every winter. The radiators was bone-dry one winter.What I know about my radiators in this house is they are heated by water, and are earth heated (geothermal energy),or jordvärme in swedish.I translated that herehttp://sv.bab.la/lexikon/svensk-engelsk/jordv%C3%A4rmeMaybe it would be a good idea to have an ESD mat also on the floor, but they were so expensive. I can't afford one at the moment.Now I only got this plastic mat from IKEA so that my chair won't wear out the nice wooden floor underneath.I'm afraid this plastic mat might actually build up some charges when I'm moving around on it :|

author: Spekkio
author_rank: Regular Contributor
timestamp: August 15, 2015, 02:00:45 pm
content: Quote from: rs20 on August 14, 2015, 09:43:29 amI might start another thread on this later, because I find this RCD to be very interesting.It would be fun to experiment with, though I have respect for mains voltage.Maybe it is possible to simulate with smaller voltages, for example take a sine wave from an function generator.I would need two signals, one that would simulate the live, and the other the neutral. they would need to be shifted in phase 90 degrees (or is it 180 degrees?).Would I be able to do something practical with that, or is it just too weak?

author: Spekkio
author_rank: Regular Contributor
timestamp: August 17, 2015, 08:18:34 am
content: I've talked to the landlord. The radiators are NOT connected to mains earth he said. But the tubes are definetly going down into ground. Ground heated water, there are loops of tubes going all around the farm field outside. And connected to some pump device in the basement. Some white box that looks like a fridge. Dont know what it really does. But I assume it is for the water.I'll still check if there is a connection from the sink to the radiator anyway.And there is no RCD in this house he said.(Feeling very tired and unmotivated today.)But he thought that it was no danger in using the radiators as ground. I might buy one of those large crocodile clips you use for your car batteries to get a good contact on the radiator. I might need to grind a little bit on the surface to get a good contact on the copper.Just an idea of a safety system:What if I get an RCD for my outlet. I found one a little bit more expensive with 4 outlets that felt like quality, but really made for outdoor use. Connect ground to the radiator from my RCD ground connection. And connect my surge protected power strips to this RCD. All equipment would all have the same common ground connected to the radiator system, and my ESD mat too ofcourse, not forgetting the 1MOhm resistors.I can feel safe in many situations? Not only from zapping my IC's.But also protected from unwanted voltage spikes.And also feel safe from any chassis getting live.. right?Or am I getting everything wrong here, or am I just being crazy?Skickat från min GT-I9305N via Tapatalk

author: McBryce
author_rank: Super Contributor
timestamp: August 17, 2015, 08:55:36 am
content: You can buy a proper piping Earth connection in any decent hardware store for pennies. They look like this:http://smg.photobucket.com/user/lewy8/media/P4130383.jpg.htmlThis will give you a much better connection than the crocodile clip.McBryce.

author: Spekkio
author_rank: Regular Contributor
timestamp: August 17, 2015, 03:29:21 pm
content: Quote from: McBryce on August 17, 2015, 08:55:36 amOk, that looks good.But the pipes are painted white, I need to remove that first. It's not really my house, I rent it as an apartment.But the part that is not painted, the valve.I thought I could get a large crocodile clip with a very tight grip and sharp teeth to put on there. And it is also easier to find in stores around here.

author: apis
author_rank: Super Contributor
timestamp: August 17, 2015, 03:44:08 pm
content: According to regulation if any contact in a room is to be earthed, all of them has to be, and only a certified electrician is allowed to do the installation.In theory you should be able to ground to the radiator, but mixing grounded and ungrounded equipment is a bad idea so you need to make sure any ungrounded and grounded equipment is sufficiently far away apart that you can't touch them at the same time. (And if you do it, measure to make sure there isn't any excessive current going to the radiator etc, old buildings can have really wonky electrical wiring.)You should only have a resistor between yourself and ground and the esd mat and ground (it's for your own protection, i.e. to prevent large currents from passing through your body to earth if you touch something at high voltage potential). The rest of the equipment should have a very low resistance connection to ground or it won't work (the current must be large enough for the fuse to blow in case of a fault).As rs20 says though, I don't think it's necessary to ground everything properly. What's important from a ESD perspective is that your equipment, the esd-mat, the components and yourself are all at the same relative zero volt potential. So if you are all hooked up to the same ground wire, even if that is not connected to the buildings earth connection/radiator, you would still prevent any esd discharges damaging your components. So, a wire and resistor from your mat/wriststrap to the same ground connector as your test equipment should be enough and you don't have to jury rig something illegal.

author: Spekkio
author_rank: Regular Contributor
timestamp: August 17, 2015, 08:06:18 pm
content: Quote from: apis on August 17, 2015, 03:44:08 pmThank you, that feels good to hear

author: Spekkio
author_rank: Regular Contributor
timestamp: September 10, 2015, 09:19:16 pm
content: I just noticed. I had my hand on my computer chassis. And then I touched the radiator. Getting small electrical discharges. Doesn't kill me. But they are strong enough to notice very clearly.As we already know. The ground connection on my powerstrip and and everything is floating. Theres no ground pin in my wall outlet.What does this say about my radiator. It the radiator properly grounded?I have built a small device with three bc547:ns in like a darlington pair except three. A diode that lights up when all transistors are open.It lights up when I hold it close to wires. It also lights when I touch the base on the last transistor ofcourse. I've isolated it so I don't touch it.But it lights up when I hold it close to my radiator. I thought if everything was peoperly grounded It would really detect any static charges around the radiators.I am confused.I found another strange phenomena with this simple device I will write a new thread about.Skickat från min GT-I9305N via Tapatalk

author: DimitriP
author_rank: Super Contributor
timestamp: September 11, 2015, 05:03:02 am
content: Quote from: German_EE on August 09, 2015, 11:38:29 am^^^^What he saidOn a good note:QuoteConsidering you are surrounded by wood, esd mat or not you are better off than in carpeted /metal/ plastic environments out there.And before you forget .... 3,1,2