How to connect ESD wristband and mat? - Page 1
Forum section: electronics / beginners

author: capsicum
author_rank: Contributor
timestamp: February 28, 2017, 09:37:58 pm
content: Yes i searched the forum and no this is not about what to use as a ground.(I was at one time a genuine certified mains electrician, I know all about solid grounding.)"To the point!" you say.I am setting up a workbench, ordered a low cost ESD mat and ESD wristband, both came with identical snap on cords that terminate with removable alligator clips(bare banana plug when clips are removed) and they have built in 1Mresistors.What is the typical cord arrangement?Mat to ground and wristband to mat(somehow,there is only one connection point on this mat, a snap-button.)both wristband and mat straight to groundwristband to the workpiece and mat to ground.(but if workpiece is largely dielectric or has poor contact with the mat?)Did I forget to order some missing connector dodads?

author: tpowell1830
author_rank: Frequent Contributor
timestamp: February 28, 2017, 09:53:33 pm
content: The idea with the wristband is to snap to your mat as you walk up to that station to work. When you are done at that station, Unsnap your wristband and walk away. Mat to ground.

author: testian
author_rank: Regular Contributor
timestamp: February 28, 2017, 10:20:20 pm
content: Have a look at this page:http://www.esdjournal.com/techpapr/eosesd/grounds/fsg.htmDepending how you are grounding you mat you cloud use something like that:http://www.ebay.co.uk/itm/Anti-Static-ESD-Earth-Grounding-UK-Plug-Various-Connections-Made-In-GB-/380809944227?var=&hash=item58aa0a9ca3:m:m0STkNTHA25EuZWTJPsLeJgand use it as ground for you mat and wristbandor:https://www.reichelt.com/?LANGUAGE=EN&CTYPE=0&MWSTFREE=0&CCOUNTRY=447&ARTICLE=60370&PROVID=2788&wt_guka=22596854417_79177434017&PROVID=2788&gclid=CjwKEAiA3NTFBRDKheuO6IG43VQSJAA74F77ukjmg92HbEguQeSzoJ12DtcSWMjLlTYIXP4Mk8HB3RoCOSzw_wcB(stackable Earth bonding point )

author: ollihd
author_rank: Regular Contributor
timestamp: February 28, 2017, 11:09:35 pm
content: Quote from: capsicum on February 28, 2017, 09:37:58 pmIn this case you can do two pretty simple things. 1. Make a slitter for the snap-button and connect mat to ground from one end of the split and the wristband to the other. 2. Just get a spare button-snap and insert it to the mat. Many videos on this on youtube. If you go with the 2nd route you can connect the mat to ground from the first button-snap and your wristband to mat via the second one.QuoteYou can do this as well since both the mat and wristband have the 1M resistors built-in. The only problem here would be you would probably need an extra long cord for the wristband? The cord would get tangled up?QuoteI suggest going with the wristband on your wrist. 1. Your body would be discharging any built up static when working on the piece 2. You always remember to put the wristband on if it is sitting on your mat vs. just shift it aside and start working.QuoteMaybe just order an extra button for the mat?The way I setup my ESD mat was with two connection points. First one was for mat to ground and second was for wristband to mat. On the outlet I have a dedicated ESD-plug (http://www.esdshop.eu/pictures/vyrobky/1obr_1226.jpeg). I also connect my ESD-storage and such to that same plug. Plug also has a 1M resistor built-in, so I don't really need to worry if I plug a cheapo chinese strap to the mat.

author: capsicum
author_rank: Contributor
timestamp: February 28, 2017, 11:24:04 pm
content: Here, I finally managed to get some pics of what I am working with.

author: ollihd
author_rank: Regular Contributor
timestamp: February 28, 2017, 11:27:28 pm
content: Mat to ground. Insert conductive material X (wire, etc) between mat and mat ground cord connection, aka. between the snap (the yellow one). Clip on to that wire / material x with wriststrap and you are good to go.

author: capsicum
author_rank: Contributor
timestamp: February 28, 2017, 11:32:48 pm
content: Quote from: ollihd on February 28, 2017, 11:09:35 pmTo clarify my intent: Wristband on wrist with the wristband's cord clipped directly to the electronic component rather than the mat or ground. With the goal to minimize hand to component potential with drainage to ground of secondary concern.

author: capsicum
author_rank: Contributor
timestamp: March 01, 2017, 02:10:38 am
content: Thanks for all the replies.Summery answer:I am missing some connector pieces.The mat is to be soft grounded, the wrist strap is to be soft grounded (not via the mat however, although they can share a bus), the workpiece simply dissipates through the mat in most situations."Hard ground" is a direct low ohm conductive path to earth."Soft ground" is a purposeful and specific high ohm conductive path, generally between 500k and 10M ohms resistive depending on conditions, high enough to limit peak currents while low enough to maintain residual potential under 10v.Found this, looks like what I need, 10mm snap/stud for the mat and two 4mm barrels for my wrist strap and a misc ground.http://staticcontrol.descoindustries.com//SCSCatalog/Grounding-Hardware/Ground-Cords/LPCGC151M/#.WLYmaFfav0oI still need a nice ground-only wall plug for looks and convenience but for now I can just make something workable to get it operational.

author: Ian.M
author_rank: Super Contributor
timestamp: March 01, 2017, 02:38:54 am
content: That will do it - or take a block of Aluminum or brass, drill some 4mm holes for plugs, and tap some holes to screw on 10mm snap studs (IIRC that's the right size) from any canvas shop, and connect it to your hard earth via THREE 470K resistors in series. Three because a single ordinary resistor has too low a voltage rating for safety if Mains is applied across it, and if there is a short across one resistor, that still leaves you safe with two in series.

author: capsicum
author_rank: Contributor
timestamp: March 02, 2017, 08:37:49 pm
content: Quote from: Ian.M on March 01, 2017, 02:38:54 amIn my location ground paths are really only for ground and are not part of the normal power circuit, if crossed directly with the hot conductor it will open the circuit breaker while maintaining ground(the primary purpose), our ground line is intended as a safety for nearly every exposed metal surface in the home or industry and is separate from the neutral conductor all the way to the final ground rod conductor which has rather strict design and quality requirements. In a commercial building if you see any metal conduit or electrical box it is part of a hard ground, as is most plumbing and metal framing, even with 480v and 600v systems. The only way for mains to flow over the ESD resistor is for me to be working with exposed mains on the bench, in which case I will be using a ground fault interrupt protection device so anything over 5mA escaping from the main circuit to any ground path or any other circuit also trips a breaker.Other than that, a few hundred volts is nothing compared to the several thousand that come with a static charge, if mains arc over is of concern to you, you would be much better served by a single resistor in line with a quick blow 5mA 250v fuse.

author: Ian.M
author_rank: Super Contributor
timestamp: March 02, 2017, 09:31:01 pm
content: Never the less, its standard to have safety resistors in all personal ESD prevention equipment, including grounding points. If there is a fault in the grounding conductor, then it can rise to typically half mains voltage even with no other faults present due to the leakage current through the class Y filter caps in parallel of all equipment with SMPSUs connected downstream of the fault.The resistors prevent the use of ESD prevention equipment increasing the risk to you if any of the other protective measures or equipment (that you should be using) fail.