Non-earthed wall sockets vs ESD-safe soldering - Page 1
Forum section: electronics / general

author: sanchaz12
author_rank: Regular Contributor
timestamp: August 16, 2015, 08:54:43 am
content: Hello everyone,As I am a beginner to hobby-grade soldering I want to invest in a good soldering setup. I have almost certainly decided to buy the HAKKO FX-888D, so I will be assured that it will last me a long time.But I just realized that the wall sockets are not grounded by any means (I live in an old house). Until now I just used a €10 "plug-directly-into-the-mains" soldering iron but never encountered any problems related to ESD.The fact is that when I buy the HAKKO, a proper insulated and ESD-safe station, the whole ESD-safe part is just not going to work when not grounded, right?There is a fixed radiator in the room I plan to solder. But I do not want to rely on my own thoughts about grounding until I know what makes a proper grounded connection.Unfortunately it is not an option to re-wire the sockets or something like that, because it is a rented house. The property manager does not want to replace the wiring and sockets to be properly grounded, nor will he let me do that myself.

author: TheElectricChicken
author_rank: Frequent Contributor
timestamp: August 16, 2015, 10:37:46 am
content: Oh the fun of having a landlord.ESD is generally not as much of a problem as people make out. Often you're not working on things that are easily broken and developing an intuitive way of touching things helps a lot. I cannot recall damaging anything from Static discharge (esd) myself, when I reach for any part of a computer I always touch the metal with my hand first, not the chips or edge connectors. Always touching the case first shorts out the static ZAP if there is one, leaving you safe to poke at the item.The other BIG fix is that heater, does it work ? Great if it does. Static electricity hates humidity. You can put an end to static damaged parts in a whole company by installing a humidifier in the building. The higher humidity just makes it harder everywhere in the building for static charges to build up.So if you are going to handle something expensive, and you are not sure, then hang a wet towel over the heater or hang up some wet washing in the room and that will help raise the humidity in the room and make it BETTER at ESD protection that 50 kilometers of curly leashes ever would.

author: nanofrog
author_rank: Super Contributor
timestamp: August 16, 2015, 01:01:09 pm
content: Quote from: TheElectricChicken on August 16, 2015, 10:37:46 amDefinitely some myths here ^.If it still works, there's no problem.High humidity solves ESD (you can still create charges ~ 1.5kV just sitting in your chair in 90% RH for example).If you don't touch it/handle it correctly, no ESD event will occur.There's some other issues with your post, such as touching grounded metal. Yes, it bleeds any charge you may carry at that time, but once you let go, any subsequent charge has nowhere to go other than the electronics you're handling. For it to work continuously, you'd have to hold onto grounded metal at all times. And this can be a safety issue for you due to the fast rate of discharge (1M resistor in the path slows the discharge rate).Finished products and some IC's do contain ESD protection devices/circuits, but simple active devices such as a MOSFET do not, and can be damaged with as little as a 10V discharge (may still work, but it won't last as long and/or may not meet it's specifications due to the damage).I'd recommend givingFundamentals of ESDa read (.pdf; might want to pay close attention to the tables on the first couple of pages if you want to discover just how easy it is to build up a suitable charge to damage or kill devices).You don't have to go nuts to put together a suitable ESD solution. For a hobbyist, a proper ESD mat (2 layer rubber versions can handle molten solder) and wrist strap properly connected will be sufficient. A smaller mat, say the size of a dining table place mat (~60cm x 90cm for example), can cut your costs to some extent. It's on the heavy side, so be prepared on shipping costs.

author: TheElectricChicken
author_rank: Frequent Contributor
timestamp: August 16, 2015, 03:08:14 pm
content: Quote from: nanofrog on August 16, 2015, 01:01:09 pmDo you even bother to google before you respond ?This is literally fourth grade physics, for 9 or 10 year olds. But hey, let's go with some anti-static underpants salesman's spiel instead that you're crown jewels can make 12kV @ 4KVA all day long.http://www.education.com/science-fair/article/temperature-humidity-static-charges-last/You claim I saidQuoteThat I actually said wasQuoteIf something is not DAMAGED, it's not DAMAGED. That is not a myth, it's basic English, what would that be, kindergarten ? I don't know I'm not even going to google anymore, if you don't even bother I can't see why I should do it for you.

author: TheElectricChicken
author_rank: Frequent Contributor
timestamp: August 16, 2015, 03:22:39 pm
content: using a humidifier is why the shuttles exploded.http://oce.jpl.nasa.gov/practices/3008ksc.pdf

author: sanchaz12
author_rank: Regular Contributor
timestamp: August 16, 2015, 03:23:08 pm
content: Well humidity is already a 'problem' here, as the humidity in most rooms is between 70-75% on a daily basis and it gets even worse on rainy days when it doesn't matter when you open the windows. It comes down to my own charge now I understand. Maybe a wrist strap connected to the radiator would do the job. Maybe also ground the board using alligator clips to the same radiator? I'm not sure if that is correct

author: TheElectricChicken
author_rank: Frequent Contributor
timestamp: August 16, 2015, 03:31:54 pm
content: If I can recommend leaving the radiator alone, connect your strap to the desk. Then don't touch things on the desk until you wear the strap. If the radiator is metal and metal pipes, then who knows what actual voltage it will bring into the room, earth potentials vary a lot, pipes often carry currents. It's just you and what you want to work on that you ground. So if the desk has no metal then a conductive mat or a bare wire across the desk with a layer of foil over that and then a mat over the top would be ok to connect to.However what I did is you think about how you give someone a ZAP and then you don't do that to the sensitive parts of the circuit, you only do it first to the metal cases and everywhere except the pins of an IC first. Then after you zap someone you can't do it again. Think of the computer as a person. You zap the person on their ear so they hear and feel it best, you aim for a sensitive part. On the computer you aim for a not sensitive part with your hand first, then you are good to touch it anywhere. Think that way, and like me, you won't damage anything.

author: TheElectricChicken
author_rank: Frequent Contributor
timestamp: August 16, 2015, 03:38:45 pm
content: Oh, and on those days when it has been raining and the window is open, Don't worry about the anti-static measures AT ALL. I would be happy to buy you replacement stuff on Ebay and send it straight to you to replace anything you can damage on a day like that using static. When it rains, humidity is like almost 100% everywhere there are open windows.

author: sanchaz12
author_rank: Regular Contributor
timestamp: August 16, 2015, 07:13:15 pm
content: Quote from: TheElectricChicken on August 16, 2015, 03:38:45 pmTo be honest that would be ideal to prevent static discharge, but I have to find a good compromise here. Some devices I have literally started rusting due to high relative humidity values and not enough ventilation. For example, in one of my older back-up/hobby pc's I found several rusty spots, even around the cpu (screws, some SMD resistors). For what I can tell, this was not the case before the high RH became a problem in this house (about 1-1,5 year ago). Have not had any malfunctioning devices yet, but it shows the consequences of having high RH in a house with bad ventilation.At my jobsite on the other hand it is a completely different story. New building, central ventilation system. We repair smartphones/tablets/laptops etc. and the RH never reaches above like 40%. No one apart from me seems to care about ESD, I've seen several smartphones 'magically' stop working after repair, and they all wonder why and get upset about it. I tell them about ESD, but they just do not care...

author: TheElectricChicken
author_rank: Frequent Contributor
timestamp: August 17, 2015, 06:21:23 am
content: Quote from: sanchaz12 on August 16, 2015, 07:13:15 pmYes, that's why I mention a humidifier, while the techies are arguing endlessly over who is to blame for destroying everything like people on a forum, one person can quietly and discreetly eliminate most of the ESD damaged items with just one quiet action.Maybe there is spray silicon or something suitable to stop corrosion ?

author: sanchaz12
author_rank: Regular Contributor
timestamp: August 20, 2015, 07:11:45 pm
content: Quote from: TheElectricChicken on August 17, 2015, 06:21:23 amWell every repair bench is in a separated room, I don't think they will invest in 8 humidifiers and if they do they would surely be forgotten to fill up.The rust in one of those computers may have already existed before all the humidity problems in our house, and may have gotten (much) worse depending on the increased RH. I can't really tell but my main computer doesn't get used that often either and there are no signs of rust in that one. It might as well has just been coincidence.Ontopic: I've just came up with an idea to create a grounding point (correct me if i'm wrong, just using my imagination...).Just a very simple solution; Earthing pin outside in the soil, run a wire to the room I'm working in and somehow connect it to a power strip.

author: TheElectricChicken
author_rank: Frequent Contributor
timestamp: August 20, 2015, 07:27:16 pm
content: Quote from: sanchaz12 on August 20, 2015, 07:11:45 pmNot so much, you are trying to connect the soldering irons, and your fingers to the item that is sensitive, which you'll solder. You're trying to short out the spark before it happens. That's the point of the whole thing. To short out the spark. So it's between the desk, so that the item is connected, or even the item itself, your hand and the soldering iron. No need to connect the outside earth really, though it shouldn't built up a BIG difference, it can build up something. So think hands and soldering iron and the item that they'll static spark to, the item itself. Short out those things.

author: sanchaz12
author_rank: Regular Contributor
timestamp: August 20, 2015, 07:38:29 pm
content: Quote from: TheElectricChicken on August 20, 2015, 07:27:16 pmThanks for the clear info. I always thought the whole point of ESD safety was about connecting everything to a grounding point, and then make sure the grounding point is connected to at what I call 'ground level'. I assumed it would possibly work the way you just explained, but something in me would say it had to be at 'ground level' to be effective. Also it wouldn't make much sense when not using a wrist strap for example, even when everything is connected to a earthed mains outlet. When you build up a charge and touch the pins of an IC for example the static electricity can destroy it no matter if the board itself and other tools are at ground level or not.That's just my summary of everything, so if it isn't correct feel free to criticize.

author: TheElectricChicken
author_rank: Frequent Contributor
timestamp: August 20, 2015, 07:45:38 pm
content: no, you're spot on and I'm glad I could help. I think just understanding it has always been the secret for me. Just touching first, the parts of the item where it won't hurt it. Touching the metal case, or, for computer cards I handle them by the metal strip that forms part of the case and you can see from outside the computer.