Electromagnetic pollution: how to protect yourself with a multi-meter?

un multimètre et moi - photo - comic

Using a small and simple voltmeter (multi-meter), you can measure the effect of electromagnetic pollution of your living space on your body. Electrical wiring, TV, fridge, lamps, computers,Wi-Fi, electromagnetic devices of any kind: they emit an EM field that disrupt your body functions.

How are we affected?

Muscles, brain, nervous system, heart: our vital functions are triggered by electrical signals. The effects of a chronic electrical disruptions are not shown yet, but many suspect that they are a source of pathologies at all levels: autoimmune diseases, Parkinson’s disease, multiple sclerosis, etc.

electrocardiogram - drawing
An electrocardiogram, as the name suggests, measures the electrical impulses of the heart.

Electromagnetic pollution, how does it work?

Let’s make it simple: any alternating current ( AC ) – or alternating tension – generate electromagnetic fields. When we think of EM fields, we think about them. Mobile, Wifi, DECT: it’s always the same principle: an alternating tension generated in an antenna emits an electromagnetic field. What varies is the frequency of oscillation, and therefore the wavelength. Also, the stronger the power, the further the wave will spread.

broadcast and reception with antennas - drawing

But there is one big culprit that we tend to forget: the electricity that provides our homes! It is also an alternating tension (230V and 50Hz in Europe, 120V and 60Hz in the United States). We know that very high voltage lines aren’t safe for health, but that’s also true for the cables that power each room we live in, as well as each electronic device. According to the laws of physics, this alternating tension radiates an electromagnetic field in right were we live.

The next step is simple: any conductive element inside an electromagnetic field undergoes an associated AC current and tension. That’s how receiver antennas work. As we are mostly made of water, we are good conductors, and we make no exception: an alternating tension is generated all over our body!

emission and reception electricity and body - drawing

Measuring electromagnetic pollution for cheap

Buy a multi-meter

To measure this tension, you must equip yourself with a multimeter. It can be found in all DIY stores, or on amazon. It isn’t very expensive: between 10 and 20 euros/dollars.

If you’re lazy, that looks like a good and cheap one:

What exactly are we measuring? The AC voltage induced in our body by the electromagnetic fields. To do this, it’s necessary to put the multi-meter in “alternating tension” position, connect one side to the ground (which serves as the reference) and the other to yourself (catch it with the fingers or to touch your body).

A tailor-made extension

You must also build an extension because it should not carry any current – which would falsify the measures! I have removed the tips of a plug so that it only has the earth, to which all the wires are connected.

bespoke male plug with that earth
It looks like a robot head!

Or an independent earth wire – no voltage around

Another option might be a cable connected to an earth cable:

  • a single earth cable
  • a metal rod plugged in your garden
  • a water pipe or tap, usually connected to the earth
Pipes connected to the ground.

At home, I can see that the pipes are properly grounded. So I can connect to this wire or any pipe of the flat.

Then, we go on an adventure… at home!

Then, we connect this extension to the most reliable earth source, and measure each corner of each room. “2 volts here, 0.5 volts there, 6 volts in this corner!” Surprises guaranteed! You will see your environment with a brand new eye.

ready plugs and cables, the body tension is often high
Around plugs and cables, the body tension is often high: 3,4V

Then try to disconnect the electrical objects (extensions, power strips, lamps..) and electronic (computers, television, internet box…), and observe the influence they have on the tension of the body.

If I touch a cable with the foot, the voltage climbs to 6.9V!
If I touch a cable with the foot, the voltage climbs up to 6.9V!

And if you walk barefoot, does the tension increase or decrease? In some places, walking barefoot is beneficial… in others, it could be harmful. Know it, and know where!

To go even further: switch off the circuit breaker and disconnect some rooms completely. What is the new voltage in your body? The difference is usually very surprising! Ever since I discovered this, I’ve been switching off the circuit breaker to see how it can affect my fatigue and my health in general. And my sleep!

300 mV: I was able to measure.
0.3V: a not-so-ideal value but very satisfying comparing to what’s I’ve measured so far.

Pay a special attention to the bedroom: electromagnetic fields may strongly disrupt sleep and prevent you from effectively recovering at night. The consequences of poor sleep are known, and they are dramatic.

A quite impressive experience: measure the tension of your body, then touch someone else. It should then increase. Crazy, isn’t it? By doing this, you increase the size of the antenna and therefore the induced electric current.

The importance of the earth

Any device that isn’t earthed radiates strongly. If your devices are well designed and grounded, they shouldn’t radiate. Earthing prevents electromagnetic radiation.

Outlets without earth

It is dangerous to connect cords or outlets designed for the earth in outlets that don’t have one. It is quite logical (if you have followed my explanations…):

Plug an extension into a groundless outlet: the alternating current emits a magnetic field. This then impacts the earth wire. Since it isn’t connected to anything, an alternating current is created in this earth wire.

Extension cable connected without ground: 99V instead of zero!
Cable connected to a socket without ground: 99V instead of zero! Danger!

If you then connect to a device that is 99 volts instead, it’ll then radiate strongly…

Earthless devices

Earthless devices may emit strongly.  If you touch them, a strong tension may run inside you!

I discovered that when I plugged my computer on a power cord plugged into an outlet with no earth: it released a voltage of 70 volts! And when I use my computer, I touch it constantly… I let you imagine my terror when discovering that! This voltage of 70 volts ran through me when I touched it! Connected to the earth, everything is fine: it’s now at zero volt and doesn’t radiate any significant electromagnetic field.

Here’s an example with my girlfriend’s sewing machine, whose power cable has no earth. The metal parts are showing a tension of 15.8 volts and therefore radiates a magnetic field. If I connect this metal to the earth, it doesn’t radiate anymore and the tension in my body decreases by 70%!

Sewing machine not grounded: 15.8V in the chassis, and 3.5V in my body.
Sewing machine not earthed: 15.8V in the frame, and 3.5V in my body.
If I connect the frame of the sewing machine to the ground: 0V in the chassis, and 1V in my body.
If I connect the frame of the sewing machine to the earth: 0V in the frame, and 1V in my body.

Connecting a device to the ground

If the frame is easily accessible (like the previous sewing machine), then you can connect it to the ground. It can be quite simple: make sure that a cable connected to the earth is in contact with the metal (and therefore conductive) frame.

sewing machine connected to the ground

It adds wires and it’s ugly (unless you bring an artistic touch), but you must choose between comfort and health / safety.

Switched off devices

And that’s not all! If I turn off the sewing machine, there remains 2.7 volts in the frame, while only 0.4 volts if I disconnect it. Turning off or unplugging a device isn’t the same thing! Think about doing the test.

Beware of bad grounding

To make measurements, it isn’t really necessary that the quality of the earth is pure. What matters is to get an order of magnitude: knowing what is potentially dangerous and what is safer. But how do we know if we can trust a earthed outlet?

If the measured induced tension in your body is stable (around a few volts max), it sounds good. If the earth isn’t good, the voltage is unstable, it fluctuates a lot and the values ​​make no sense.

danger - comic

Warning: some people plug themselves directly to the ground (“grounding”). Do not do this unless you are sure of what you’re doing: the electromagnetic pollution must be low and the earth has to be of quality (without interference caused by the electric wiring of the building).

Then you can measure the other earth outlets from the one you know is good: pull an extension cord and measure the AC voltage between the two outlets. We often get surprises!

A limitation: high frequencies

The multi-meter is very effective for measuring pollution from electrical installations and electronic devices. On the other hand, it doesn’t measure very well the EM fields with higher frequencies: my telephone had no effect on the measured tension of my body. That doesn’t mean it doesn’t radiate: it’s purpose is to emit (and receive). Likewise, the impact of the Wi-Fi or DECT phones isn’t flagrant. Do not conclude that they are harmless!

An indicator: if the alternating tension frequency of your body is 50Hz, it’s purely electrical pollution. If it’s more (100 or 200Hz), then it’s a mix of electrical and other pollutions (such as wifi).

Grounding, a measurable phenomenon

Grounding is a movement that encourages walking in nature with bare feet. I won’t discuss grounding methods indoors here, which may involve risks.

Put on your flip flops and get onto some lawn. Plant a metal object (like a tent peg) in the ground: it’ll be the earth. Yes, in case you didn’t know, a ground cable is a cable connected to the ground, as simple as that. Measure the tension between the metal object and you. Then redo the experience with bare feet on the grass… this should surprise you!

grounding: zero body voltage

If it doesn’t work, there may be several reasons:

  • there is no electromagnetic pollution and your body is nearly zero volts
  • the soil isn’t conductive (too dry, too sandy…)
  • you haven’t been nice to people lately

We are too often disconnected from the ground and this certainly impacts our health. But I’m not going to go further on grounding, which is a big topic to cover.


This discovery was for me very impressive, and very scary. I had seen some videos on Youtube of people with voltmeters, but seeing this for yourself, in you own home, that’s something else!! I felt like a kid wanting to measure everything with my new toy!

I now consider this approach as essential to limit the impact of electromagnetic pollution and help the body it’s proper electrical behavior, in order to get back to health.

I hope you already have ordered a multi-meter or that you are ready to go to the nearest DIY store. Take some measures and tell me in the comments what has surprised you the most!

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