Safe to Use? Pinless Extension Cord Without Grounding Connected to 3-Pin Receptacle

Is it safe to use a pinless extension cord connected to a pin receptacle?

It does not bother you at all, you will only have electric shock protection in the connected receivers (those that require it).

Are you able to explain why in a way that a layman could understand?

If you connect anything with a plug to such an extension cord just with 2 pins it will be OK. These are these types of plugs:
http://www.manta.home.pl/zkwiecien/rtv/kable/mm81/www/11.jpg

This type of extension cord can be used for all receivers that are made in class 2 insulation and come with cables with flat plugs, so these receivers do not require a protective conductor. is the continuity of the socket protection pin - the power cord, extension cord.

An extension cord plug with pinless sockets usually does not fit into a pin socket - this pin has nowhere to enter.

If the equipment you are using has a grounded plug and there is a phase short to the chassis and this ground is connected where it is needed, the fuse will blow out; if the grounding is not connected (because, for example, you used an extension cord on the way, which has no pins), it will be 230V ~ on the housing. If the installation has a differential fuse, it will then detect that someone has touched the housing and immediately turn off the voltage; however, if there is no such fuse in it, it will end in electric shock.

_jta_ wrote:

If the installation has a differential fuse, it will then detect that someone has touched the housing and immediately turn off the voltage;

It is not very appropriate for a colleague with the signature of a specialist to talk nonsense on the forum. And that's dangerous nonsense. The RCD does not work as a colleague thinks and it was not designed to do so.
Coming back to the topic, each electrical device has a record in the manual to what socket it can be connected. And this is what you should stick to. Be it a socket in the wall, in an extension cord or on the ceiling. Connecting inconsistent with the instructions may cause damage to the equipment, electric shock or other losses for which the manufacturer will not be liable ...

As far as I know, the RCD cuts out the voltage if there is a current flow of a suitable value between the network and the ground. If you think it works differently than I think, then describe how it works.

The RCD will switch off when there is a sufficiently large difference in currents in the L and N cores, if the voltage is on the housing, the current from L will flow to PE and the differential will be blown. Nobody has to touch it.

_jta_ wrote:

An extension cord plug with pinless sockets usually does not fit into a pin socket - this pin has nowhere to enter.

My colleague probably got something wrong with the plugs of the old GOST system, which will not fit into any socket of the current standards with a ground connection, although new Chinese-made extension cords with such a plug are available on sale. Extension cords without a protective connection are manufactured with a CEE 7/17 plug (https://commons.wikimedia.org/wiki/File:CEE_7-17_plug.jpg) which allow for insertion into French and German standard sockets. On the other hand, the aforementioned "flat" plugs, ie CEE 7/16, also called "europlug", are limited to 2.5 A. Thus, more powerful devices require a larger plug (with or without earthing), so you cannot put everything in one bag.

I have not noticed these CEE 7/17 plugs on sale. I do not know what system, but what I see in stores does not go into the socket with a pin.

AdamFilipek - If the housing is not grounded, does not touch something grounded, or is not large enough that the current through its capacity is enough to trip the RCD, the same phase short to the housing will not trip the RCD, but most likely the RCD will trip when someone touches it simultaneously to this enclosure and something grounded. Human body resistance at 230V ~ is small enough for the current flowing enough (and probably with a large margin) to trip the RCD. I hope that the RCD works quickly enough in such a situation that those who touch it hardly feel the current.

I have the impression that Wikipedia is a bit confused - reading what they write there, you can get the impression that the RCD will only limit the differential current to about 20mA - and from what I know, this is a protection trip, and if the current exceeds a certain threshold, it turns off the power and requires manual activation to restore them.

_jta_ - I admit that what you wrote has some sense in my opinion - the only question is whether the current flowing through the electrocuted person to the ground would be enough to trip the RCD.
I misunderstood - that this "detection" would happen if the PE is connected.

And as for the use of an extension cord with pinless sockets - if I lived alone, maybe I would take a risk that I would remember to connect only class II devices to this extension cord.
But when living with a family - why risk it?

_jta_ wrote:

If the housing is not grounded, is not touching something grounded, or is not large enough that the current through its capacity is sufficient to trip the RCD, the same phase shorting to the housing will not trip the RCD, but most likely the RCD will trip if someone touches the RCD at the same time. this case and something grounded. Human body resistance at 230V ~ is small enough for the current flowing enough (and probably with a large margin) to trip the RCD. I hope that the RCD works quickly enough in such a situation that those who touch it hardly feel the current.

Stop writing these stupid things because someone else will believe you and follow your "advice".
You are an electronics engineer, stay with it. Electricity is governed by different rules.
Now, before explaining what you asked back for syphilis, please answer my questions.
1) what if a person who suffers an electric shock of 30 mA while the RCD is triggered stands on a high ladder and falls as a result of the shock? And believe that you can really feel these milliseconds of electricity.
2) What if the RCD fails? And it is quite an emergency apparatus.
3) What if the sum of the resistance along the path of the shock current (including the damaged body) takes a value such that the current is 20mA? It is a current that in certain cases will not allow for self-release, and at the same time can be lethal. RCD will not turn off because it's not 30mA ...
I suppose I have indicated at least three reasons why a two-wire extension cord cannot be used with a device in protection class 1. Even as there is an RCD in the installation.

If the current flowing through the affected person to the ground is small, it does not cause muscle contraction, but only slightly unpleasant sensations and a reflex withdrawal of the hand. If a larger muscle contraction occurs, the current increases at the same time (the contraction causes more pressure), and the RCD switches off.

Unfortunately, there is a possible situation that the RCD will not protect: you connect two devices, each has a breakdown to the housing from one of the wires from the plug, but one from the phase, the other from the neutral - someone touches both housings at the same time, and the RCD "sees" it as normal load.

In addition, someone may be more sensitive to current (eg, has a pacemaker), and may be seriously harmed by the flow of a current that the RCD will not respond to.

You didn't answer the questions. And you keep going.
So I translate and explain. First, let's take the TN-CS installation on the wallpaper. Of course, I assume a properly made installation and conscious connection of devices. The differential current will close in the L-breakdown-PE circuit. We are interested in what voltage will appear on the housing of the device. For simple calculations, let's take RPE as 0.5 ohms. This is a real value, of course, the one seen by the RCD. So let's calculate the maximum voltage on the case. 30mA x 0.5 ohms. As soon as 0.015V appears, the RCD will disconnect the power within a few milliseconds. Do you understand the difference between 0.015 and 230?
We go further. In the same installation, the RCD fails. 230V appears on the housing, we count, 230 / 0.5. current flows over 200A. Why so many and not 460? Idea. But also download the B16 characteristics and see when the power is disconnected. It is this B, selected depending on the IPZ of the circuit, that constitutes the basic electric shock protection. RCD is an additional protection. About TT and the cascade will be in the next lesson ... ?

You've made a mistake: the mains voltage will not appear on the grounded housing, even if there is a short circuit to the phase. Can you guess what you missed?

Agree that it is better to have both the case grounding, and the RCD. However, I believe that in the absence of grounding, the RCD is not useless.

Besides, there are still many TN-C installations in Poland without RCDs, and they pose the greatest threat to users.

_jta_ wrote:

Besides, there are still many TN-C installations in Poland without RCDs, and they pose the greatest threat to users.

It is not the type of installation that is the problem.
The problem is that they are neglected without periodic maintenance. In principle, there is electricity, it is ok. How many such flowers are there, tiles, wallpapers and burned Alu underneath.

And the fact that there are many installations made of aluminum wires without proper connection is also a problem. What's worse, they were often made irreparable (well, you can repair them by breaking the walls to lay new wires). There is also a lot of TN-C from which there is nowhere to get grounding.

A separate issue is the quality of new installations - I once went to the hospital, because the fitter did not tighten the screw on the connection of the earthing wire and the equipment casing was live (not a breakdown, but leakage, summed up from many devices), I saw the equipment burned as a result of a faulty connection in the installation (phase connected to the earthing pin!), someone struck someone from the new installation in front of me (and before the commissioning, I reminded the management that we already had a faulty installation, that I would check it - assured that it would be well checked) ... professionals, since they often do this (most of the installations that I have watched), what after frequent inspections, how do they miss such fluff? Probably, if it was me who did the review, I would catch them, but if someone does it often, they probably fall into a routine, connect the instrument and do not look at the indications, but only write that it is okay. I do not know, maybe you need devices that, when they detect that something is wrong, require the alarm to be cleared, and not with a single button? Or they write in non-erasable memory that there was an alarm and when?

_jta_ wrote:

I do not know what system, but what I see in stores does not go into the socket with a pin.

You should find out who is the importer of this crap and report to the Office of Competition and Consumer Protection, where the CE marked product with a plug that is not used in the EU came from. GOST plugs in Poland were forgotten with the fall of communism, and even in the times of the Polish People's Republic, plugs in accordance with CEE 7/17 were produced in Poland. In addition, GOST plugs have pins with a diameter of 4 mm and a load capacity of 6 A.

@_jta_ I believe that it is wrong to do the installation, e.g. add a socket and finish it, believing that everything will be fine. Only after carrying out the measurements (IPZ) it turns out that something was wrong. So far, from my practice, I can count such cases as "eggs", but what I have recently encountered can be classified as a "miracle" - a miracle that for some 30 years the house did not burn down and that it did not kill anyone. It is a pity to write about it, because I argue really professionally that you cannot see what the bunglers were here.

Where there were the accidents I wrote about, each time it was about a completely new installation, including security features.

You should find out who is the importer of this crap and report it to the Office of Competition and Consumer Protection

If you think so, report it. Product: Ps-360 / 1.5m; producer: "JONEX" Adam Jonczyk, NIP 673-104-78-58; Carrefour sold it. Has the CE marking; 10A / 250V ~; OMY 2x1.0mm2 cable (oh, something thin, for 10A). The next time I visit Carrefour, I will see if there are extension cords with CEE 7/17 plug (# 10). The pins look thicker than those of the old 6A plugs.

_jta_ wrote:

However, I believe that in the absence of grounding, the RCD is not useless.

How would the circuit close for "differential" current and RCD trip in the absence of grounding?

I used to think like you, too, but it doesn't make sense for logic.

How would the circuit close for "differential" current and RCD trip in the absence of grounding?

So if someone touches the phase while standing on the ground and current flows through it, this will be the differential current that the RCD will detect. And thanks to this, that someone will be exposed to the flow of current for a tiny fraction of a second, instead of waiting for someone else to figure it out and turn the power off manually.

The difference in exposure time will be of great importance when it comes to harmfulness - once the fitter showed me that when he touches the casing with his hand, then first with the back of his hand - because if there was tension, the muscle contraction would move the hand away from the casing, instead of catching it.

_jta_ wrote:

So if someone touches the phase while standing on the ground and current flows through it, this will be the differential current that the RCD will detect. And thanks to this, that someone will be exposed to the flow of current for a small fraction of a second

Maybe standing on bare ground, barefoot, or in wet shoes or in a damp bathroom. Or by touching L and a grounded water pipe at the same time. In each of these cases, however, there is a differential current flow to "ground". Otherwise, such as a dry floor or a carpet in an apartment, the current of 30mA is unlikely to flow. I understand the flow of current through all capacities (the neon lamp in the tester is burning on this principle) but there is too high impedance to trip the RCD. Anyway, maybe I shouldn't write this, but I once did a test by touching the top of my hand to the phase conductor in the apartment, with the other hand in my pocket for safety, and apart from a slight tingling sensation in my hand, there were no other sensations, the RCD did not work either. Maybe because these were not the conditions for a life-threatening electric shock, so it is right that the RCD did not work. In my opinion, however, the PE conductor should be and should be properly connected to provide protection together with the RCD.

When you stand on a vinyl flooring, the electricity is barely enough to glow a neon lamp - but such electricity does not pose a risk of electric shock.

The worst case is that if they connect L to one socket and N in the other, the user will connect devices to both with the housing connected to the earth pin, and then with one hand touch one of them and the other touch the other. And for such a situation, the RCD will not help.

But in terms of voltage it could be worse: two sockets, both have an L on the ground pin but different phases. Perhaps this situation destroyed the equipment that should be able to withstand 250V ~ - but the interfacial voltage was much greater.

Coming back to the plug from # 10: I was in Carrefour (Galeria Mokotów), I looked at extension cords without earthing pins, and none of them had such a plug - they all had plugs that do not go into the earthing pin sockets.

Over 10 years ago I bought an extension cord in a well-known shop "for dorks". I remember that I overpaid, and only later realized that I had bought an extension cord without grounding. Returning to the topic, you can clearly see the plug suitable for the sockets with a pin, 2x1 mm? cable. It's hard to define the producer, probably Chinese food anyway.
Another proof that the quality of consumer goods has fallen sharply.

_jta_ wrote:

It's almost the worst if they connect L. to one grounding pin socket.

Well, for such stupidity, it won't help. The only hope is that only devices in the second protection class will be supplied from such a socket and that no one will touch the grounding pin. Therefore, periodic measurements of the installation are a legitimate requirement.

As for an extension cord from a hypermarket, equipped with a plug that does not go into the socket with a pin, could you upload a photo of it? Because it is quite strange, currently every plug produced should fit into a socket with a pin. The times of "full" plugins are long over. I even recently wanted to buy such an original "antique" plug for my old tube radio and I have not found it anywhere except at antiquities auctions.
However, when I was looking for an extension cord without grounding, all of them were equipped with plugs as in the link from post # 10

Here is a picture of the plug of this extension cord:

Because it is quite strange, currently every plug produced should fit into a socket with a pin.

According to information from BANANvanDYK on 06 Aug 2018 22:40, the manufacturer states that the standards do not allow an extension cord without grounding, with ordinary sockets for round plugs, matching a grounded socket (such as in # 25). On the other hand, I have seen (and even have) a splitter that fits into a socket with grounding, and has sockets for flat plugs - apparently the assumption is that devices with such plugs can be used where sockets have grounding pins (without a splitter, they can also be connected ).

That is, devices that do not have a grounding or are insulated well enough to be safely used in all conditions, must have round plugs without a hole for the grounding pin; also extension cords and multi-plugs should not allow connection of such equipment to a grounded outlet.

By the decision of BBJ SEP, the extension cord from post # 25 does not meet the requirements of IEC 60884-1 (and the Polish version of PN-IEC 60884-1: 2006). The reason is the use of a class II plug with a class 0 extension cord.
Current. "Standard-compliant" extension cords can be equipped with class 0 plugs (preventing insertion into a class I socket - with a protective pin) and a class 0 extension cord (enabling the connection of class 0, I, II device plugs).
To quote the content of the opinion:

Quote:

(extension cord from post # 25) poses the greatest potential risk to the user. This is because it makes it impossible to use additional protection in class I devices (in the form of protective earthing), even when powered through an extension cord from an appropriate fixed plug socket with a protective pin.

Quote:

(an extension cord with a class 0 plug) poses a slightly lower risk to the user, preventing the connection of such an extension cord to fixed plug sockets with a protective pin. Nevertheless, it ensures safe use of the appliances, as with the previous extension cord design, only with regard to Class II appliances

Quote:

(...) would be to allow the use of extension cords (...) with warnings attached to them that the extension cords provide an appropriate level of safety for the use of devices only in the case of:
- powering them from socket outlets without a protective pin only in the case of using devices of class II

And here we come back to the topic, because such class 0 extension cords will constantly raise questions whether class I devices can be connected to them. How would the manufacturer publish a warning? Probably on the packaging that will go to the trash.
Master level question: what does a socket for connecting class II devices (except flat plugs) look like? Unfortunately, I cannot access the above standards for free.
In addition, there is a stalemate with the standards presented. They do not provide for the use of class 0 plugs. For many years, class 0 devices have been withdrawn from use in many countries, and the sale of new ones has been banned.
There is an aspect of the old building standards that required safety pin sockets only in the kitchen and bathroom. In other rooms it was believed that there would be no risk of electric shock. In practice, we take a class 0 extension cord connected to a socket without additional protection in the form of an RCD, we put, for example, a tinplate computer (class I) next to a radiator (grounded CO with steel pipes) and we have a potential risk of electric shock.
So the question is, why are class 0 sockets still produced when they are phased out?

Quote:

However, I have seen (and even have) a splitter that fits with grounded sockets, and has sockets for flat plugs

Flat plugs are class II. The splitter can be inserted into a socket with a pin, but you cannot connect class I devices (requiring grounding) - everything is fine.

BANANvanDYK wrote:

Master level question: what does a socket for connecting class II devices look like?

It is like in the picture above, the higher power receivers have a round shape.