ESD Mat and wrist strap grounding - Ground hole not available in my country

Question

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.

Any help is appreciated!

EDIT:

I've got 3 cables in the inside of the receptacle I showed above:

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?

Answer 1

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:

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.

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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.

Answer 2

You don't actually need to bond your ESD mat to earth. People do, but there is really no need.

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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.

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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.

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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.

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Equipotential Symbol:

(Functional/Chassis) Earth Symbol:

Answer 3

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.

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).

Answer 4

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.