ESD Mat and earth binding post - Page 1
Forum section: electronics / beginners

author: Moriambar
author_rank: Unknown
timestamp: August 21, 2020, 12:45:20 pm
content: Hi.I "recently" moved to a new apartment and created a new bench to work on. I thought to do things "properly" (excuse my newb terminology) and also bought an esd mat and earth binding post to ensure "esd-safety".The bench is wooden and it has a metal structure, with rubber feet.That is nice but I actually do not know how to proceed to use the mats/earth binding post. I get that the mats should probably be connected to the post but the post itself should be connected to the chassis of the bench or should I call an electrician and make him bind the ground terminal to the actual ground of my apartment?Is there anything else you think I need?cheers

author: srb1954
author_rank: Super Contributor
timestamp: August 22, 2020, 06:12:06 am
content: Connect the mat connection through to the mains earth via a 1M1W resistor.The resistor provides a path for static charges to leak away but protects against shock if there is a fault in the mains wiring and the earth pin becomes live.

author: Ian.M
author_rank: Super Contributor
timestamp: August 22, 2020, 07:26:04 am
content: Italy, along with many other parts of southern and eastern Europe, has a certain reputation for questionable electrical installation practices, especially in older buildings. If your new apartment is in a relatively new building, built this millennium, odds are the wiring is up to current standards and three pin (or two pin + side ground contacts) sockets should have their protective ground properly connected to Earth ground. If you are in an older building however, grounding may be questionable. For peace of mind, I'd strongly recommend checking all sockets in your workshop area with a three indicator light socket tester, which can usually be found in the electrical isle of any reasonably large DIY store. If any faults are found with the tester, or if you are in an old building, and there is metalwork near your bench that may be grounded (e.g. pipes etc. or architectural metalwork) I strongly recommend consulting a qualified electrician familiar with your local electrical regulations.Shuko style ESD grounding plug adapters are readily available. If you use one, make sure the socket's side spring contacts for ground are in good condition with adequate contact pressure. If not, replace the socket!.If you build your own ESD grounding plug, make sure its Line and Neutral terminals are adequately insulated, and use two 510K resistors in series with the ESD ground connection, so you are still protected if any single fault compromises one of the resistors. 10mm press-studs (the size commonly used for ESD grounding connections) are available from any good canvas work supplier, and most marine chandlers. Add a countersunk machine screw through the middle with a ring terminal, spring washer and nut to use them as a panel mount ESD grounding connector. N.B. Do *not* do that on a metal panel directly connected to supply ground, without insulating washers and sleeve on the bolt to prevent the stud shorting to the panel, as you need that 1Meg series safety resistor to protect you against electrocution if you touch a live terminal while in contact with your ESD ground. In theory, there should also be a 1Meg resistor in the lead from the ESD ground point to your wrist-band, and the wrist band connector should also have a protective resistor, but both are items that are likely to be replaced frequently, and unless you pay a premium for traceable western manufacture, there's always a risk that a dangerous fake (without a safety resistor) will creep in which leaves the 1Meg resistance between your ESD grounding point and supply ground as your last line of defence against electrocution.

author: Moriambar
author_rank: Unknown
timestamp: August 22, 2020, 10:19:26 am
content: Quote from: Ian.M on August 22, 2020, 07:26:04 amThanks.My electrical installation has been completely redone in 2019 by a qualified electrician and meets the latest EU standards (with certification too!).So I guess a schuko-esd adapter will be the choiche. I do not trust myself with mains so it's either that if I can find it, or something similar done by my electrician.thanks a lot