About grounding and emi 2

Ganitta28 · February 20, 2025, 9:24pm

I can’t finish my post on grounding and emi waves (if an administrator can contact me, so I will continue my post here. As asked here is how I filtered the EMI, using ferrites, they simply clip near the connector you want to isolate.

Here at the outlet of my power supply.
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I did the same for air assist etc. By the way I switched to a high quality OFC copper shielded USB cable quality.
I received my new 4A power supply, which completely removed my worries about stopping in the middle of work. In fact when I engraved at 70% of power all the work stopped without reason, suddenly problem solved BUT
There is still a GOAL…
I focused on the original power supply, which being undersized, I discovered a major concern and DANGEROUS!
here is the socket for the new 4A power supply.

Standard socket with a well-sized three-conductor cable, 1 phase, a neutral and an earth.
Let’s compare to the original shot!

One side seems normal, three holes supposed to be 1 phase, a neutral and an earth, BUT it is vicious and dangerous as desired,
Look at the other side, the power outlet, a phase, a neutral and OOPS no earth!
What would happen if there was a problem, overheating, electrocution, fire?
I am lucky my home is equipped with a differential circuit breaker (mandatory in France, but especially old homes are very often without one), which would prevent me from electrocution or a fire, before I could feel anything, I tested with a nail driven into the socket (don’t do that at home or anywhere else!!!) I am still alive because the differential cut the electricity in 1/1000th of a second.
In short, all this to say that the machines are often sold for savings, with power supplies specially sized in amperage, unfiltered, not EMI shielded, and without grounding! To good readers.

MikeyH · February 20, 2025, 9:34pm

Not enough information to make a safety determination. Not all devices must be grounded. Neither of my laser power supplies (USA) came with a ground wire. The risk of starting a fire with the laser head is much greater than starting one with the power supply.

Ganitta28 · February 20, 2025, 9:43pm

We do not have the same electrical standards, here we are in 220v and, beyond a certain electrical power, a 3-pole conductor is MANDATORY, as is the use of a differential circuit breaker.
Read my post carefully, the passage with the photos of the original socket which half copies a 3-pole socket (just and one plug and not two) and the socket of a quality power supply with poles at each end. With a 2-pole socket that could be disconnected in the event of a problem. There is not even the bare minimum to protect you from electrocution (grounding).

MikeyH · February 20, 2025, 9:58pm

Electronics Technician since 1968
Journeyman Electrician since 1982
Amateur Radio, Extra Class License

I did read it carefully. I am also aware my 120v can kill you just as fast as your 220v.

Terminology is different, but devices are the same. The real question is whether or not that device is approved for sale in your country. Made In China means it may not be, but as the consumer, you have to protect yourself. If you do not feel safe, send it back and get an acceptable replacement.

Ganitta28 · February 20, 2025, 10:06pm

90% of machines or almost 95% of their components do not come from Mars, but from China,

MikeyH · February 20, 2025, 10:10pm

Yes, but do they meet electrical standards mandated by your country?

Ganitta28 · February 20, 2025, 10:12pm

the goal is to warn people and make relevant observations to improve the machines with simple updates, the pleasure of engraving but also the safety of users. I am an informed person due to my technical background. And I’m not kidding about Chinese equipment, it is omnipresent in all areas, even in rockets and satellites, as in processors and other cutting-edge uses of technological advances, and what everything that comes from China has not invaded all the countries of the world, technical or electrical standards respected or not?

soniclab · February 20, 2025, 10:13pm

Likely the standard is to the receptacle and not to the actual device. Where exactly are you located ? You are correct with most EU plugs have to have the safety insulation on the plug terminals. Most china plugs will not have compliant cords… even worse when you open the power supply and find there is not adequate mains separation / isolation. No ground is usually not a safety concern as much as actual mains isolation.

If you are concerned I would simply replace the power supply with something compliant to your local electrical code.

Ganitta28 · February 21, 2025, 7:14am

Hello, I am in France and I have already replaced my power supply with a real power supply with 3 real poles on the socket, my machine chassis is grounded for safety against EMI waves.which has reduced machine shutdowns to almost 100%, partly by switching the power supply to 4A and partly by EMI shielding. I still have to check when I have time what is happening with the dlc32 motherboard!
Mains current level my house is earthed thanks to an earthing rod but also thanks to the 30mA differential circuit breaker (standards required in France, and I’m lucky, they are applied at my house).
Sincerely

jkwilborn · February 21, 2025, 1:09pm

All of this doesn’t ensure safety. Only if you get across a hot pin and earth ground will the gfi be able to detect it.

If you get across the mains, you’re just another load for the 240V system.

I’m interested in how a differentiated gfi works, I know how differentiated lines operate, but can’t seem to grasp how this work without extra connections of some sort for the other half of the differentiation.

I know how dangerous mains are, in the USA about 80% of the electrocutions are due to household mains. Even at 120V.

Worked over 30 years in industrial cnc and computers, in all that time, I have found only one case I could track down to efi issue. This was caused by a high power radar unit about 30 miles away.

Usb data lines are differentiated and should alleviate any efi introduced into the system. However, there seems to be some really cheap usb cords out there.

I have a heater that is mains powered and it has no ground, so to speak. The whole heater is in a plastic case, so, in theory, there is no way to come in contact with the mains.

EU has much better protections (in software and hardware) than we do in the USA.

Thanks for posting

Ganitta28 · February 21, 2025, 1:42pm

A differential circuit breaker works like a measuring device. It compares the intensity between the Neutral and the Phase of your electrical installation. To put it simply, it constantly monitors the current entering and leaving your home.

As its name suggests, the differential circuit breaker automatically cuts the current in the event that you have a difference between the two conductors of the circuit.

If the currents entering and leaving your home are different, this means that there is a leak, as you might imagine on a water pipe. With electric current, it is the same, but it is very dangerous to have a loss of current. As a safety measure, the circuit breaker trips.

What is a leakage current?

It is important here to define the leakage current. It only appears in the event of a fault. In most cases, it is a fault in the insulation of one of your devices (washing machine and dryer in most cases).

The risk is to end up with a current flowing through the casing of the appliance. If you touch it, it is electrocution, or worse. This is where the differential circuit breaker comes in, it will cut the current as soon as it appears to protect you.

For a leakage current to be established and therefore detected, you must have a good quality earth conductor connected to the sockets to be measured. This is why it is important to have your installation checked when you move in. In the case of a new installation, a certification body must come and carry out a check to authorize the power supply.
I can guarantee that you do not become a burden on the sector, I have already put a nail in the 220v socket (my electrical installation is new, checked 2 times and up to standard), the circuit breaker acts before the metal touches the conductor of the socket, in fact it acts when the electric arc occurs, o’ should not be very far from the speed of light (theoretical speed of electrons in a perfect conductor, plus the latency time of the electronics.
if I cut a live cable with pliers, same thing. If a device starts to overheat to a certain extent, or catch fire, the circuit breaker will do its job perfectly, after which the device can continue to burn, but it will no longer be for emi in industry it is much simpler, higher standards, superior material and many limiting factors come into play, e.g. a building in metal like many industrial sites, plays the role of Faraday cage. (emi, elf, etc)
In my home, a simple refrigerator can disrupt many devices, especially TVs and hi-fi systems, although much progress has been made. EMI waves can be detected with ec a simple radio station, it is the parasites as for vehicles. In fact there are electromagnetic waves everywhere of all frequencies.Remember the old TVs, what we called snow (black image with moving white dots) are only the visualization of emi waves, vestiges of the big bang.
In IT, believe me it’s even worse, hence the gold-plated conductors, shielded cables, etc., as for quality hi-fi! vAs t This is a subject I am going on and on about (sorry) but I prefer to give understandable details in order to avoid critical emails from those who do not want to or have not understood!
Afterwards I can also be wrong and admit my wrongs and errors! xd
Sincerely, a beginner engraver but old-timer in cnc and harcare computing

Ganitta28 · February 21, 2025, 2:02pm

Et

parsec · February 21, 2025, 2:50pm

I agree with almost everything, but to add / clarify, the earth leakage circuit breaker (and perhaps the GFCI?) act even if the leak is between neutral and earth. A 10ma earth leakage circuit breaker even protects against fires because it “almost” trips before the arc happens, for example where a mouse has made a nest (flammable material) and chewed through a wire.
Some very important points that are missed in Portugal:

There are many water heaters installed without their circuit protected by a 30ma earth leakage circuit breaker.
Many people don’t test the earth leakage circuit breaker every month.
There are earth leakage circuit breaker on sale from various well-known brands that don’t work (the test button works but they don’t act on a leak in the circuit) and installers don’t test the circuit, resulting in FALSE protection.

Ganitta28 · February 21, 2025, 3:33pm

not to advertise, but I only use Legrand. But be careful, unfortunately there are copies, mine cost €130…it seems expensive but in fact not if we look at the services provided

soniclab · February 21, 2025, 7:38pm

I believe the author is referring to an RCD. Residual-current device - Wikipedia

parsec · February 21, 2025, 7:41pm

I believe they have a similar function…

Pete.IRL · February 21, 2025, 7:47pm

I see what I think is a 0.5mm wire guage on the photo of your power supply cord which as far as I have read is the lower end of CE guage.
My question regarding this is. Does a smaller guage wire generate more heat, and therfore give off more interference…and of what kind.

I have located a company that sells plated USB cable conectors that use gold and nickel for good clean data stream and speed.

I also did some very interesting reading since your last post on this subject and found conflicting opinions. I can only assume it is related to individual, environmental and set-up situations.

Ganitta28 · February 21, 2025, 8:49pm

Good evening and thank you for reading
This is a very, very complex subject that can go as far as the quantum level!
To answer your question simply, you should never use wires with a lower section, risk of fire! Current folds in a thinner cable create, in addition to EMI waves, significant heating through a combination of effects such as Jouls, Foucault, Laplace, Lorenz,… it is very complex,
A conductor section is adapted to a certain voltage and has a cert in number of amperes, i. it is obligatory to respect these standards of section of wires.
The high voltage cables of the electricity pylons are very thick, there is a reason for that! Conversely f Passing a low voltage through a large cable results in a huge loss of current, the electrons are slowed down or even completely converted into heat, which is itself dissipated in the conductor and therefore not necessarily observable with the hands.

and the mandatory standard in France with the cable section in mm².

soniclab · February 21, 2025, 9:21pm

Yes, they have exactly the same operation.

You can see the current transformer around both legs. Since they are opposing in phase they will cancel each other out and no current will be induced in the transformer ring. Only under imbalance or short circuit will the phases be imbalanced and a current will be measured over the current trasnsformer.

Ganitta28 · February 21, 2025, 10:13pm

exactly, but nowadays we use more of an electronic comparator system.