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I'm building my new lab and I'm not sure where to ground since I live in the Netherlands; we only have hot and neutral available, I don't see a third a hole.

I understand I should get an ESD mat and wrist strap that includes the 1Mohm resistor. And ground these 2 with a common-point ground as shown here http://documents.desco.com/pdf/tb-2000.pdf

The ESD mat should also include a 1Mohm resistor in order to soft-ground it as well, but I'm a bit confused as to why wouldn't the non-conductive top surface be considered a soft-ground for the bottom-conductive layer.

However, my question is about how should I ground the the common-point ground. Should I unscrew the third hole on my wall socket a bit and tie it there? I'm a bit lost how to continue, all the tutorials I see on the internet always include a dummy plug with ground connection to a hot-neutral-ground wall socket, which I don't have.

Wall outlet

Any help is appreciated!

EDIT:

I've got 3 cables in the inside of the receptacle I showed above: Removed outlet outer plastic

Is the top right cable (kinda grey-ish) the ground that I need? If so, then can I just replace with the other outlets containing a ground prong?

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    \$\begingroup\$ Go look in your power distribution point (Dutch: "meterkast"), chances are that there is wire connected to the (copper) pipes of the water and gas. This wire should connect to a grounding pin into the earth below the house. If this is the case then your waterpipes and very likely the heating pipes (Central heating: CV) are grounded as well. You can use that as an ESD ground but you MUST use a 1 Mohm series resistor to make this safe. With the 1 Mohm, ESD can "escape" but no harmful current can flow when something touches the mains live. \$\endgroup\$ Sep 7, 2020 at 12:31
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    \$\begingroup\$ "I live in the Netherlands; we only have hot and neutral available" That's not true. Your receptacle (wandcontactdoos) doesn't have a ground, but most (if not all) houses do. Take a look at your kitchen, do you have deeper receptacles there? If the kitchen is build/renovated in the past couple of decades, you should. And the ground is at the sides or at top and bottom. Does your distribution point (meterkast) have an 'aardlekschakelaar'? \$\endgroup\$
    – Mast
    Sep 7, 2020 at 12:41
  • \$\begingroup\$ @Mast, yes I do have the receptacle with the ground on top and bottom on the kitchen. I also have the aardlekschakelaar. At the moment I also have a surge protector which has the top and bottom GNDs as well, but it's connected to the hot-neutral receptacle (I don't have the other kind in my lab room). Can I then replace this receptacle by the one with grounded sides? If so, how can I then ground the ESD math into it? \$\endgroup\$
    – ErnestoG
    Sep 7, 2020 at 20:57
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    \$\begingroup\$ You can only reliably replace the receptacle with a ground-available one of there is a ground connection available in the mounting box in the wall. Leaving it disconnected internally wouldn't do you any good and would be a code violation. I wouldn't bet it's available, so there's some work involved if you want to go that route. \$\endgroup\$
    – Mast
    Sep 8, 2020 at 5:03
  • \$\begingroup\$ @Mast, check my edit. Do you think having those 3 cables (Assuming the third one on the top-right is GND) are good to go into a new receptacle containing the GND prongs? \$\endgroup\$
    – ErnestoG
    Sep 17, 2020 at 9:21

4 Answers 4

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You can't. All you can do is follow Tom's advice of the equipotential.

I'd highly recommend to pull a ground wire trough the pipes to somewhere it is available. (eg: bathroom, kitchen) And replace it for one of these: enter image description here

This is a bit of work, I know. But worth it! Since aside from ESD there are other problems of not having a earthed lab. Such as leakage currents in smps (all your gear) but most important is personal protection.

While your at it, check if you have an RCD in your distribution panel (meterkast). You'll recognize it by a breaker switch that has a test button. Press it, see if it works.


The worst advice given is to connect ground of your lab to the copper pipes of the heating system. This may work for you, and this used to be a normal thing, until plastic piping became available.
Besides plastic piping, the plumber won't expect pipes being used for ground and could get shocked when he cuts a pipe.

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    \$\begingroup\$ shocked by what? \$\endgroup\$
    – glglgl
    Sep 7, 2020 at 8:12
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    \$\begingroup\$ Please note, that if you change one outlet, you have to change all outlets in the same space. Because in the Netherlands, it is not allowed to have grounded and groundless outlets in the same space. \$\endgroup\$ Sep 7, 2020 at 9:55
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    \$\begingroup\$ @Jeroen3, the rule is still, if you adapt a section, you have to adapt the entire section. \$\endgroup\$ Sep 7, 2020 at 11:13
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    \$\begingroup\$ I don't know NL rules, but a general principle is that you shouldn't make things worse than they were before. Having some but not all class 1 equipment in a room grounded is arguably more dangerous than having none of it grounded. \$\endgroup\$ Sep 7, 2020 at 13:12
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    \$\begingroup\$ @PeterGreen The rules are very vague. They say you should update the installation to the latest standard if you make big changes. What is considered a "big change" is up for debate. If you say you must apply the latest standard you also probably have to change the height of the sockets and the color of the wiring. (ground is mandatory since 1996) \$\endgroup\$
    – Jeroen3
    Sep 7, 2020 at 13:52
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You don't actually need to bond your ESD mat to earth. People do, but there is really no need.


The idea is not really to earth yourself, but rather to create an equipotential region. You want to keep yourself, your mat, and any components at the same voltage - whether that be earth potential or the potential of your ESD mat.

  1. Set up an ESD mat on your desk (basically just unroll it). This is your equipotential level. Connecting it to earth is optional.
  2. Bond yourself with a wrist-strap to your ESD mat. You are now at the same potential as your mat.
  3. Place any components or circuitry (still in its ESD protective wrapper) on your mat (or pick it up). The ESD wrapper/packaging is now at your equipotential level.
  4. You can now unwrap and handle the parts as there is no potential difference between you and the parts.
  5. When not handling, place components on the ESD mat. They remain at the same potential as you and the mat are bonded together.
  6. If you want to place the components somewhere not on your ESD mat, place them back in ESD protective packaging, allowing them to be safely moved to a different potential.

For things like soldering irons, ESD safe irons will usually have an equipotential bond point (marked with a circle inside a triangle, see below). Connect this bond point to your ESD mat, and the iron is now safely at the same potential as your mat and components.

(If the iron happens to be earthed through its socket as well, your mat is now earthed, but if not, it doesn't matter).

For things like test equipment, these usually have a functional earth stud (marked with an earth symbol, see below). Connect this to your ESD mat, and your test equipment is now safely bonded to the same potential.


If you feel you must earth your mat and don't have an earthed socket around, you can instead use something like a copper pipe if you have one (e.g. radiator or water feed) if these are bonded to earth.


Equipotential Symbol: circle inside a triangle

(Functional/Chassis) Earth Symbol: ⏚

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    \$\begingroup\$ Yeah. The main reason you Earth your ESD setup that anything left to sit around for a long enough period of time will leak away accumulated charge and approach earth. So earthing your ESD setup just means that it will probably already be at or close to the same potential as an object you just picked up somewhere nearby without needing to take extra steps to equalize the charge. \$\endgroup\$
    – DKNguyen
    Sep 6, 2020 at 21:24
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    \$\begingroup\$ WIthout earthing your setup, if you keep happening to continue to place charged objects onto the ESD setup, the charge will equalize to the ESD setup building up charge since it has nowhere to drain and raise it above the surroundings and nearby objects which makes it able to charge objects that come into contact with the ESD setup to bring them to the same potential. But this is not that big an issue with dissipative surfaces. It's more of an issue with conductive surfaces where the charge equalization can happen rapidly and that is what causes damage. \$\endgroup\$
    – DKNguyen
    Sep 6, 2020 at 21:29
  • \$\begingroup\$ How good is the connection between the ESD mat and the alligator clip to your ESD bracelet? (I'm speaking of the rubbery blue mats, in case there are more than one type.) If it's clipped to the edge, is there a very low-resistance connection between the metal of the bracelet and some random point on the mat? Could you, for example, run a small light bulb from a battery through that connection? \$\endgroup\$
    – Keavon
    Sep 8, 2020 at 11:49
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    \$\begingroup\$ @Keavon The dissipative layer of the mat is high enough resistance that a regular multimeter with regular probes will read overload when measuring resistance. It won't short out circuits except for extremely high impedance, leakage current sensitive circuits (the kind where moisture, residues, and finger oils also mess up). ESD bracelets also have a 1MOhm resistor built in for protecting the user from faults. The term "dissipative" is defined as between 1MOhm and 10GOhm. Conductive is less than 1MOhm \$\endgroup\$
    – DKNguyen
    Sep 8, 2020 at 15:33
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I also live in the Netherlands and these contacts are indeed quite common. However, I assume somewhere in your house you also have the ground version (see picture below), which includes ground.

enter image description here

I'm not a technician, neither a professional electronics guy, however, I suggest you connect your ESD mat to a version like above. Another reason to do this, is that you want your soldering iron, possible oscilloscope and other gear to be also properly grounded (and on the same ground).

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Mats and wrist straps are not the only measures you could take to prevent ESD. In fact, they are only effective if people keep using them at all times. They won't help you in many cases, e.g. when a colleague comes to your desk and points to the connector you ought to use and ZAP! The connector is dead despite you wearing the strap and having the mat on your desk. You may still need them for compliance in some cases.

There are ESD sprays (to be applied on the tables / chairs e.g. by your cleaning personnel) which keep static electricity under control and require no effort from the staff once they are applied. Anti-ESD floor carpets are available too, as well as anti-ESD shoes.

If you have to use mats/straps and need a ground reference, look for wide conductive structures in your building which are exposed, and try connecting the ground point to those Iron heating pipes are a popular option. This is better than just connecting the strap with the mat, as the equipotential zone you'd create in this way will be limited to the desk and your body (and only when you're wearing the strap). Connecting to building-wide structures is an attempt to extend this protection to other people in the building, though this attempt can make things better or worse, depending on the construction of the building. You should check if it helps before deciding to used it in daily work.

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