First electronics lab: building my ESD workstation - Page 1
Forum section: electronics / general

author: 3rj4
author_rank: Regular Contributor
timestamp: December 19, 2019, 12:07:32 pm
content: Hi all,I'm a newbie who's looking to get started in the electronics space. With the help of people on this site (as well as Dave's videos), I've started purchasing equipment to set up a home electronics lab. My most recent purchase was the EEVblog BM235 Multimeter.One aspect that I am paranoid about is equipment and human safety. I've started researching how to set up an ESD workstation, which led me to this thread:https://www.eevblog.com/forum/beginners/esd-grounding-question/Shock's post in the aforementioned thread contains some great videos on how to set up an ESD workstation. However, the problem is that, given my inexperience, I'm very hesitant to work with the mains; nor do I don't have access to any metal (such as pipes) that are connected to earth ground, as was suggested in the video series.So how should I go about building my ESD workstation? Must I work with the mains? If so, then how can I do so safely?I'm not even sure if the BM235 is safe to use with the mains in Australia (is it?). I'm thinking of buying one of those outlet testers, since my understanding is that they're a cheap, safe, and mostly-accurate way to ascertain as to whether the mains are at least working properly. Does anyone have any recommendations for good outlet testers in Australia?I've already searched for most of the relevant equipment (ESD matting, wrist straps, ground cords, etc.), but I'm waiting until I have a good idea of how to set up the ESD workstation, so that I know everything that I need, before I place my orders for everything.I would greatly appreciate it if people could please advise me on this.

author: BillB
author_rank: Unknown
timestamp: December 19, 2019, 12:49:25 pm
content: I'm wondering if this question might be best handled in the beginner's section of the forum? Anyway, by "working with mains" do you mean in this case using the ground in the mains outlet?You are going to want your workstation to be grounded to the mains ground, and use proper ESD mats and straps. There is no danger to you using the ground from a properly wired outlet. You could buy an outlet tester to ensure it is wired properly, but you already have that nice new meter you can use as well! (Yes, its safe to use on your mains)There are literally hundreds of tutorials/videos on how to use a DMM and how to measure/test a mains outlet; I suggest searching them out and get comfortable using your meter first.

author: 3rj4
author_rank: Regular Contributor
timestamp: December 19, 2019, 12:59:25 pm
content: Quote from: BillB on December 19, 2019, 12:49:25 pmAhh, you're right; I posted this in the wrong section. I'd appreciate it if a moderator could please move it into the appropriate section.Yes, I'm referring to using the ground in the mains outlet, but I'm also referring to using a multimeter to check that the mains outlet is working correctly (as was done in the aforementioned video).

author: Berni
author_rank: Super Contributor
timestamp: December 19, 2019, 01:01:40 pm
content: No need to be concerned with ESD this much.You can test your electrical socket for earth continuity using a multimeter. Set it to ohms, stick one end into the ground prong and other end to something else grounded (like a radiator or tap) to make sure there is a few ohms on there and things should be fine. If you want to be sure you can also test trip the RCD by connecting a incandescent light bulb between live and neutral. Having working earth in your socket is the most important in terms of safety.But when it comes to ESD yes you should be mindful of it, but its not as scary as some make it sound. If you rub your feet over a nice fuzzy carpet and the touch a circuit board while you feel a painful zap in your finger then yes its possible(but still not garanteed) you blew up something on that board. Otherwise its difficult to damage most chips with static. Yes there are some special parts that really are super sensitive to ESD, but that is usually really specialty stuff like RF chips that work at >10GHz and such. So no, you do not need a ESD mat and ESD bracelet and ESD labcoat and ESD shoes, air humidifier etc... All you have to do is make it a habit of touching something grounded when you sit down at the bench. It can be anythyng, the metal case of a desktop PC, the metal shield on a USB cable, the BNC on your scope... etc This will safety discharge you to earth in the case you did build some static charge on the way to your desk. If its getting hot and you take off your sweater, touch it again to discharge before touching your work. Getting into a habit of this will pretty much prevent ESD damage to your boards.But if you do want to get a bit of a upgrade in terms of ESD the most worth it is the ESD mat. Not only will it provide a good grippy durable heat resistant work surface but its makes sure anything on it is discharged and when you rest your arms on the mat you will discharge yourself, so it makes the discharge habbit more convenient since you often rest your arms on the worksurface anyway. If you don't want to wire the mat up yourself, then you can buy a ready made mains plug that brings out only the earth wire to a banana terminal or something.

author: 3rj4
author_rank: Regular Contributor
timestamp: December 19, 2019, 01:17:05 pm
content: Quote from: Berni on December 19, 2019, 01:01:40 pmThis is what I'm primarily concerned about. Is my multimeter appropriate for sticking into the mains? Even if it is, should I even be doing such a thing as an inexperienced person? Another problem is that I don't have a tap or a radiator nearby; in fact, I'm not even on the ground floor, so finding something grounded to put the other prong to is a problem.

author: Berni
author_rank: Super Contributor
timestamp: December 19, 2019, 01:40:20 pm
content: Don't worry the BM235 is a pretty well built meter so it should be perfectly safe for mains use. Yeah i would tend to recommend to not touch mains if you don't know what you are doing, but just testing the earth prong is safe since a correctly wired earth prong is always safe to touch. That's the very point of earthing, its a potential that is safe for people to touch so electrical appliances connect earth to any exposed metal that could come in contact with a person. This is also why having working earth connection is important for safety.If you don't have anything earthed close by then you can simply plug an extension cord into the socket you want to test and run the cord to something else earthed to do your earth resistance test there. You should measure under about 20 Ohm and and less than a few V AC between the earth prong and the other earthed object.If you find something that does not look right then contact an licensed electrician to come test your sockets for you and fix any issues. You could just get him to test it for you in the first place but that might be a bit expensive for just taking a look at a few sockets and leaving. So its worth having a quick test yourself and call him up only if you find a problem that needs fixing. Given that you are in Australia you will need a proper electrician to actually legally fix anything mains related anyway.

author: jogri
author_rank: Frequent Contributor
timestamp: December 19, 2019, 01:59:28 pm
content: You can probe a mains outlet with your multimeter, just make sure that you have your probes plugged into the volt jack. The BM235 is rated for 300V @CAT4, that means you can use it to probe outlets up to 300V RMS (australia has a mains voltage of 230V RMS [for single phase outlets]). The CAT4 part means that you can use it to probe outlets that are outdoor (and a bunch of other stuff). If you look at the included probes, it says "rated 1kV 10A", so they are also up to the task.So, your meter can handle it BUT: If you don't feel safe working with high voltage, don't do it. If you haven't worked with electronics before i'd recommend you start at 5-12V (that's enough to power your own circuits) and get used to handling your multimeter before you put it anywhere near a 230V line.

author: Black Phoenix
author_rank: Super Contributor
timestamp: December 19, 2019, 02:15:36 pm
content: Quote from: jogri on December 19, 2019, 01:59:28 pmLet me add this:So being CAT IV it's safe to use on CAT II environments.From this document, a good read:https://content.fluke.com/promotions/promo-dmm/0518-dmm-campaign/dmm/fluke_dmm-chfr/files/safetyguidelines.pdf

author: 3rj4
author_rank: Regular Contributor
timestamp: December 19, 2019, 02:29:24 pm
content: Quote from: Berni on December 19, 2019, 01:40:20 pmQuote from: jogri on December 19, 2019, 01:59:28 pmQuote from: Black Phoenix on December 19, 2019, 02:15:36 pmThank you all for the information; I appreciate it.My next question relates to where we attach the loop in Australian socket-outlets. In thishttps://youtu.be/Z-GVxM9O6jA?t=383video, we can clearly see that the US socket-outlets have a screw for this purpose, but as can be seen herehttps://upload.wikimedia.org/wikipedia/commons/thumb/b/b1/Australian_Socket-Outlet%2C_Auto_Switched.jpg/1280px-Australian_Socket-Outlet%2C_Auto_Switched.jpg, there doesn't appear to be such a thing for the Australian socket-outlets. For the Australian version, I'm presuming that we're supposed to use a "grounding plug"https://www.mektronics.com.au/static-control/grounding-points-cords-plugs/clipsal-grounding-plug.html?

author: Berni
author_rank: Super Contributor
timestamp: December 19, 2019, 05:51:42 pm
content: Yeah US are one of the rare places that have metal faceplates on outlets, because its exposed means it has to be grounded, so the screw ends up grounded too.For most other places in the world that use non conductive outlet faceplates you just use a mains plug and take the earth wire. You could use any power cord for that, but buying that grounding plug you showed is the best option, it only allows connection to earth so there is no way to mess it up.