Installation of Class C Surge Arrester Behind Main 20A Fuse in TN-C Standard Apartment Switchboard

Maybe a friend can do that. However, please note that one SPD will be short-circuited. It can be successfully eliminated.

kiss
-DAREK-

Hello!

But it will be needed when it is replaced wlz
In addition, errors shown in the drawing should be marked and inaccuracies in the description explained.
The PEN conductor should be placed on the PE rail.
My colleague's description shows that the receiving installation is still in the form of a two-core one and the colleague only replaced the switchgear.
If so, the use of an RCD is not only unnecessary, but also prohibited and harmful. And reconnection of once separated PE and N conductors is highly inadvisable.

As for the harmfulness, opinions are divided on this issue buddy kkas12.

A friend replaced the switchgear at home, from old fuses to overcurrent circuit breakers, single-phase installation. He used a differential circuit breaker with the N circuit disconnected last and connected first. The owners had a small child who put a nail into the socket on the left side [phase], before the kid was seriously hurt, the RCD reacted, which in the case of TN-C acted as a direct contact protection [current leakage from the phase conductor to earth]. The kid is still alive and well, but he got really scared... it's scary to think what would have happened if it hadn't been for the RCD. The kid would've been baked alive before he dropped a B10.

I know that soon there will be voices that the PEN must not be interrupted, because the phenomena of induction and we deprive the connected devices of protection, this applies to inductive loads, accelerated motors, etc., which after disconnecting the power supply and remaining in motion can act as a generator ... in this case I 100% agree that the application will be harmful, because we will deprive the devices connected to it of any protection. When disconnecting the power supply through the RCD, we disconnect both circuits and nothing has the right to introduce a foreign potential to the housing, because the receiver becomes separated. And the nature of the load in an ordinary house is almost purely resistive.

If the RCD is installed in a TN-C system, the following conditions must be met:
- 200% certainty that this is the final receiving installation and by turning off the power [by interrupting the PEN], we turn off only the premises we use and no other, so as not to deprive someone of protection by breaking the PEN and leaving the power on L.
- RCD with delayed switching off of the N circuit and earlier switching on.

I omit the fact that the installation should already be made as a 3 or 5-wire, because these are the regulations now ...

Hello

Krzysztof (kkas12) as always did not disappoint and noticed mistakes.
Connecting the PEN from the power supply to the RCD and then to the PEN bus is unfortunately a common erroneous practice. Not to mention the old topic of RCD in TNC but you can see that there are those who, like colleague Miwhoo - see some things differently. If the installation is aluminum - it is worth considering replacing the wires with copper ones (3x). By the way - what does 200% certainty mean.

kiss
-DAREK-

200 is more than 100, I don't think I need to explain it :)

The author did not mention a single word about the aluminum installation. Otherwise, I only see a child who experienced a close encounter with a phase, and his life was saved by a differential switch ... that's the whole philosophy ... we can only judge the one who installed the RCD in the TN-C, did it right or wrong. Is it bad that the baby survived?

All receivers had protection class II, so nothing was connected to the housing placed on a non-insulated surface, so the installation functioned properly...

This was one isolated case.

Hello!

"He who interrupts PEN has no sense." my friend Miwhoo . Keep this in mind or change your profession.
Of course, you can't watch the child because the adults have their own activities and the RCD will watch over it. It is not possible to use accessories with working terminal covers because we have an RCD.
A wonderful panacea for stupidity, shortcomings and sloppy work of ignorant electricians without imagination.

Will not a truck cutting a turn and ramming a passenger car driving correctly from the opposite direction give a colleague the idea to drive in the opposite lane when cornering?
And if the phase in (this socket) was on the right side, what conclusions would a colleague draw from this fact?

Well, I didn't really mean such conclusions, but now that they've been made...

It's not about the lack of supervision over the child, or the lack of plugs in the sockets, or even less about trucks cutting corners.
"RCD as a panacea for people's stupidity", in this statement we are probably closest to the truth.

The use of RCDs in the final receiving circuits [when we are sure that the PEN will be disconnected only in our part of the installation and nowhere else] in the TN-C system does not pose a threat, and is an effective means of protection.

When using a circuit breaker with delayed disconnection of the N line and with advanced switching on, it does not deprive the device of protection, because first the phase is disconnected from it, and only after a while the PEN, after which the receiver is separated. It works the other way when switching on - first the PEN track to ensure protection, then the L track.

Without an RCD, a significant current flows through the human body in the case of a direct shock from the phase conductor, which may not trigger the overcurrent circuit breaker until the person's heart stops, say B10, in the case of an RCD, 15-30mA flows through the body, after which the circuit breaker separates the receiver.

It is an indisputable fact that the application becomes troublesome when we have receivers in the 1st protection class, because then the principle of operation of the RCD does not allow for the correct functioning of the installation and unjustified shutdowns occur. It also does not protect against the effects of dangerous voltage on the housing of the 1st class receiver, but it protects against PEN breaks in front of the RCD.

The RCD is for supplementary protection and in a sense it protects against human stupidity. The condition is, as I wrote earlier, the use of a P312 type circuit breaker, where the phase track is disconnected first and the PEN as the second [last], and vice versa when switching on ...

If the phase was on the right side, it would probably end up in fear.
P.S. Anticipating the facts, the provisions in the standard 60364-4-41 know.

Let's get back to the topic, because it wasn't about RCD ...

Hello!

My friend Miwhoo first you make a (nonsense) lecture about the role of the RCD in a place where it has no right to be used and then you regret that

Quote:

Let's get back to the topic, because it wasn't about RCD ...

It's not fair.

Knowledge of PN HD 60364-4-41 does not apply here, except for one remark in which it prohibits the use of RCDs in the TN-C system.
To understand this issue, it will be more useful to know PBUE, which never allowed (except for special cases not applicable in residential installations) to interrupt the protective-neutral conductor today called PEN. Of course in justified cases this track had to be interrupted last and switched on first. (Does your colleague uncritically use four-circuit switches today, always and everywhere?)
However, it was rightly assumed that each such connection is a potential failure causing a lack of continuity and thus full voltage on the housing of receivers made in the first protection class.
Do not write only that currents flowed through this wire, because such reasoning sooner or later will lead to a discussion that modern RCDs also interrupt the protective conductor, on which a voltage "dragged" from the outside may also appear.

A device in protection class II does not pose a threat, regardless of the arrangement of the installation that supplies it. A correctly connected class II receiver does not pose such a threat today. This is clear when we compare where the RCD must be used and where it is just an expensive and sometimes even annoying gadget.
Today, RCDs must be used in bathroom circuits, in all socket circuits and probably in tight spaces with surfaces limited by conductive walls.
Why?
Well, because the point here (apart from stationary receivers in bathrooms) is to prevent electric shock in the event of damage to the insulation of such a (portable) receiver. In other words, we accept the injury but do not allow the injury.
And let it stay that way.

Old installations should be liquidated and not resuscitated, dear custodian of the Vistula electrics open-air museum.

What will the RCD give in the final lighting circuits, where a luminaire with protection class II can be used? Do these circuits today, regardless of the protection class of the luminaires, have to be equipped with a residual current device?
No, they don't have to.

Quote:

... PEN disconnection will only be in our part of the installation and nowhere else] in the TN-C system does not pose a threat, and is an effective means of protection.

Not true, because in this case the risk is high, because there may be a situation when a voltage appears on the receiver in the 1st protection class and will be maintained for a long time until the circuit is closed by the human body.

Such nonsense suggestions and, inevitably, the resulting discussions make the brains of young adepts not fully familiar with the principles of electric shock protection. Acting in good faith, they introduce a threat that was not there.
So don't help them idiot by saying no electric shock protection without a residual current device.

Buddy Miwhoo
I know that 200 > 100, I was just asking what 200% certainty means. But I can see from my colleague's statements that I will not wait for an answer.

As for the RCD in TN-C. This topic has been covered up and down on various forums. So I propose to end it, because the discussion will be fruitless anyway.

kiss
-DAREK-

You are right Col. Darom, one could write a long time on this topic, because the topic is extensive. It's not about us hanging dogs on each other and insulting each other, my friend kkas12, because I'm no curator, although some installations are actually suitable for a museum. In my statements, I try not to offend other forum users and I would like the epithets not to be used in relation to me either...

From your and my answer, one could draw arguments against and draw such arguments for a long time.
I'm not going to convert anyone to my views, because this is not a holy war, so I propose a peaceful ceasefire, because we probably won't get along anyway.

The author (smith01) wrote:

Quote:

The installation is in the apartment in the TN-C standard, i.e. 2 wires, I made this diagram, I have the installation divided into N and PE, through a differential switch as in the diagram

And:

Quote:

the installation in my apartment is copper, 2-wire,

Quote:

I just renovated myself

If your friend has a Certificate of Qualification, they should cancel it for you! If not, I advise you to read a bit more about where you should - and where you must not install residual current devices. Once you write about the PE cable, another time about the 2-core receiving installation, and another time about the TN-C installation. Not to mention you can't see the difference between network and install. I don't think you understand the issue. It is dangerous...

Ps. Possible supporters of rcd in TN-C I refer to the search engine or professional literature.

Hello friend smith01

If the installation in the apartment is made by a colleague as a 3-wire system (L, N, PE wires), then the drawing will be:


If there is TN-C in the apartment, then of course there will be no RCD.
Anyway, I've already gone crazy - after all, my friend has this third wire or not.

kiss
-DAREK-

smith01 wrote:

Oh shit, I'm a bit confused (joke) so, the installation in my apartment is copper, 2-wire, I just renovated it previously, I had 3 old fuses, I made a new board, I installed a differential switch, all connections of the light socket I gave separate fuses, there was a problem with creating a PE bus so as to make 3 wires, i.e. PE rail, I made a topic on the forum here's the link:

https://www.elektroda.pl/rtvforum/topic1136041.html

as it was explained at the end of the thread, I made a rail, I made a PE rail, so I am asking for someone to explain to me how to make an overheat limiter, I mean to protect the equipment in the apartment and I have a bit of it, plus now I am making a connection to a fairly large air conditioner.

You've been doing this for a long time. It was in 2008.
It's not cheaper to call a professional.

To all the malcontents who insisted that in the case described by the author, the differential circuit cannot be used, I will ask a question - have they heard about the TN-CS installation?
And why can't a differential be used in the described installation? After all, the PEN cable has been separated into PE and N and as long as they are not connected behind the differential, the installation will work without any problems. And it makes sense to install surge arresters before the differential only between L and PEN.

I greet everyone

janek

jiwaniuk wrote:

To all the malcontents who insisted that in the case described by the author, the differential circuit cannot be used, I will ask a question - have they heard about the TN-CS installation?
And why can't a differential be used in the described installation? After all, the PEN cable has been separated into PE and N and as long as they are not connected behind the differential, the installation will work without any problems. And it makes sense to install surge arresters before the differential only between L and PEN.

I greet everyone

janek

I advise you to read all posts carefully.

Especially for Kol. Jiwaniek.
Quote from the first post:

Quote:

Recently I made a whole new switchboard I have installed a differential circuit breaker, 30mA, The installation is in the apartment in the TN-C standard, i.e. 2 wires , I made such a diagram, my installations are divided into N and PE, through a differential switch

So the author modernized the switchgear - separating the neutral conductor into N and PE - but the remaining part (receiving) of the installation remained according to the old TN system standards with zeroing in the main role. In your opinion, is making a distribution in a modernized switchgear without a sufficient analysis of the receiving installation (circuits) in terms of the presence of zeroing (the author writes about the receiving installation in the TN-C standard) is the only criterion for installing a residual current device?

Quote:

have they heard about the installation of TN-CS?

A very strange question. Especially if, in the described case of alleged TN-CS, there are old 2-wire circuits on the side of the receiving installation, where the electric shock protection is implemented by "zeroing". It is not enough to modernize the switchgear to assign the characteristics of the TN-CS system to the entire installation.

Hello!

The basic and very important question is in what system does the receiving installation work, i.e. behind the switchgear (in which the PEN division was made)?

Kol. kkas12, after all, the author clearly wrote: he made a separation - but the old 2-wire circuits in the TN-C system remained, so zeroing. I think he knew what he was writing...

Hello!

He just wrote what he did.
He divided PEN into PE and N.
PE starts and ends on the busbar in the switchgear.
The neutral wire "went" into the installation.
So we have L and N phase.
So there is no question of a TN-C system.
It is also not TT because there PE (it doesn't matter that only in the switching station) is not created as a result of PEN division).
In addition, the N conductor in each system is a working conductor. Therefore, it cannot be connected to accessible conductive parts, and once separated from PE, it cannot be connected again, which will happen when it is connected to the housing of the receiver earthed by foundation.
.

He only wrote what he did, and did not write what he did not do - and did not remove the bridges in the sockets. That's for sure. Anyway, he won't admit it now...
You probably don't think that the author has all devices in protection class II and such an installation (without the PE cable) has the right to exist in a residential installation.

This whole guessing is unnecessary from the very beginning - the author does not understand any of it anyway and a careful observer will notice that the questioner lacks the knowledge to do it right. I advise you to read the topic carefully.

Hello!

Of course, I do not think that all the receivers that the author has are made in protection class II and I do not think that he removed the bridges in the sockets and/or replaced them with non-protective ones.
If this were the case, we would be dealing with a TN-S system, but (note) without the protective conductor.
And so we have a hybrid, i.e. a corpse (two wires) resuscitated by force through the use of a residual current device, which in addition cannot even be named.

It's just strange that there are people who support such a solution.
I wonder if they would sign it if they made it or if they found it during the installation measurements?

Quote:

It's just strange that there are people who support such a solution.
I wonder if they would sign it if they made it or if they found it during the installation measurements?

I have always been against such solutions . Will they sign? I do not think that if someone performs measurements reliably and knows what they are doing, they will not sign it, because even that is difficult to name, let alone consider correct and safe. At the end of this stormy discussion, my colleague's favorite sentence:
"The more you know, the less you can..."

After getting acquainted with the given topic, I came to the conclusion that my friend smith01 is probably looking for some naive Internet volunteer teacher who will devote knowledge and time - about three, five, or maybe more years, depending on mental resistance, but I don't think he will find one - unless of the same level of knowledge of electrical engineering as himself.

Please do not overdo it and hire a competent electrician.