Connecting Oven and 2-Phase Induction Hob to One Cable with 3F Fuse: Load Distribution Query

Hello

There is a 5x2.5mm2 cable running from the box and the 3f fuse (3xB16). Later, in the kitchen box, another identical cable is connected to the island via WAGO.
Here in this box I want to leave with one phase for a 3kW electric oven.
The board on the island probably has a maximum capacity of 6kW and requires 2 phases - I will connect the remaining ones.

Is such uneven load distribution acceptable? Sometimes 3kW goes only on L3, sometimes 5kW goes on L1 and L2 and nothing on L3, etc.

One more question about connecting 2f induction, terminals L1 and L2 should have up to N up to 240V, do I connect any phases for induction (those apart from the oven) or do I take L1 - L2 from the fuse according to the markings and would it be good? And L3 will go to this oven.

Such a 3f fuse trips when I overload any phase above 20A, right?

Thanks a lot

The 4x cable itself disqualifies it from being used... The topic of the oven and the hob has been repeated many times... All it takes is a slight mistake in installation and both are on fire. A separate and separate circuit must be connected to the oven. It`s over, period. This saves no money and only causes more risks. What colors of veins do you have in this 4x2.5? It should be separated neutral and protective. There are two left for the phases. What are you going to do about it?

Shadowix wrote:

The 4x cable itself disqualifies it from being used... The topic of the oven and the hob has been repeated many times... All it takes is a slight mistake in installation and both are on fire. A separate and separate circuit must be connected to the oven. It`s over, period. This saves no money and only causes more risks. What colors of veins do you have in this 4x2.5? It should be separated neutral and protective. There are two left for the phases. What are you going to do about it?

But the error, of course 5x2.5! Colors like those on cable? PE, black, blue, gray, pictorial.

I had a separate circuit, but in this place we put the refrigerator, from this place I also connected other sockets and the hood
There was a socket where the oven is supposed to be, along with the countertop sockets for the fridge... also not very good.
So I have an idea to go under the cabinets with one free phase (of course also from the same PE and N can) for the oven and the remaining 2 phases for the hob on the island.

Why should the oven and the hob burn if they are not connected interphase, e.g. L1 and L2 instead of N and L1?

Modification is possible, but forging, painting, etc.... and I`m already fed up with the messed-up kitchen... is it safe to clean the free phase not used by the hob?

krzys-iek wrote:

Modification is possible, but forging, painting, etc.... is it safe to do the cleaning with the free phase not used by the board?

Poland, however, is the kingdom of myths.
Buddy, you are honest because at least you write that you don`t want to anymore.
At least you didn`t use the official excuse of "mycologists" (which according to them is a reason to absolve all blunders) that forging is out of the question.
So do it right, buddy, while you still have the chance.

krzys-iek wrote:

Such a 3f fuse trips when I overload any phase above 20A, right?

It`s hard to understand what you wanted to convey here, but if you connect it to the 5x2.5mm2 cable, the truth is that its protection cannot exceed 16A

Good old electrode. Instead of explaining or pointing to the post where it has already been posted, I get arguments about myths or spelling (moderation)

:-)

Why is switching to the oven from the unused phase a totally bad idea? The electrician will connect it, but I will prepare everything for it. In theory, it is possible to run a separate cable for the oven, but I don`t want to because the cable for the original oven already powers two other sockets (which will be used very, very occasionally) and the hood (300W) and the fridge. Then I would have to drag the cable from the previous place under the oven socket. A job for a few days.

PS
I found https://www.elektroda.pl/rtvforum/topic3176601.html

According to this thread it is possible.

However, these are two separate devices, one of which is connected via a socket, so it requires the presence of an RCD, while the other does not require this device because it is permanently connected. Moreover, we have known for a long time that a four-track RCD protecting single-phase receivers powered from different phases is a category of malpractice.
Moreover, this circuit should be protected with three-pole protection.
Moreover, this solution will effectively prevent the possible future use of a receiver using three phases.

Of course, you will do what you want, but why did you create this topic?
Is it to get the right solution or to get applause for your idea?

krzys-iek wrote:

Why should the oven and the hob burn if they are not connected interphase, e.g. L1 and L2 instead of N and L1?

And it may catch fire due to a weak N connection from the 5x2.5 wire powering five and the board.

The electrician suggested an RCD for each phase for the entire house, but he bought it in an expensive wholesaler, so I took it without the distribution (he didn`t say it was a malpractice). He said something about the failure of one of the phases and it would be better to have a separate RCD for such a case. Well, if I bought it cheaper myself, I would have a separate RCD at the same price, but I don`t.

This is what it looks like:



I read that the left and right are usually separate devices, so they seem to come from separate phases ( here`s what the board looks like from the inside )

The oven and the hob do not have a cable with a plug, they are permanently connected!

What I don`t want is to burn anything with this connection or damage the discs. If a 3-pole fuse pops out due to a short circuit in the oven and disconnects the hob, it is not a problem for me.

Looking at my switchboard, can you already see the error caused by the 3f RCD?

Is the correct solution just to redo the cabinet?

I came to ask whether using the third, free phase would damage something... and whether I can take any two phases under the board or does it have to be L1 and L2, e.g. looking at what comes out of the LS 3F fuse.

Added after 12 [minutes]:

Shadowix wrote:

krzys-iek wrote:

Why should the oven and the hob burn if they are not connected interphase, e.g. L1 and L2 instead of N and L1?

And it may catch fire due to a weak N connection from the 5x2.5 wire powering five and the board.

I drew the connection and in fact, if the box broke off due to the force N from the switchboard side, L3 would reach L1/L2 in the hob through the oven and there would be interphase 400 - smoke and a problem.

But the same would happen there if there was no oven and the hob itself? L1 and L2 without N connected - will 400 flow through two circuits of the board (see its diagram above)?

If there is an interruption in the N track in a four-track circuit breaker, the devices powered by the circuits that this switch protects will be damaged. And there have been such cases.
Besides, the layman`s theory about the lack of protection without the use of RCDs, as I see, has been applied.

krzys-iek wrote:

I read on the disc that usually the left and right are actually separate devices

Another layman`s fairy tale.
A three-phase motor connected in a star also consists of three single-phase devices?
It is one device, no matter how it is built. It`s not up to the user to decide about this.

That is:

You recommend modifying the switchboard so that instead of 3f RCDs, at least for devices (the second one is for lighting) 3x separate 1f RCDs. I will remove the fuses from the phase indicator and it will fit (the phase indicator will get some small ones on the cable). I don`t understand if the electrician is also a layman and it looks like in the photo or if it`s just me :P

Until the switchboard is modified, is it possible to connect the oven and hob on one circuit (my original question)?

Should I use WAGO or a clamp with high-power screws (black Bakelite ones).

I don`t recommend anything to you because you still don`t understand anything because your main theme is a stove and an oven on one circuit.
A permanently connected board does not require an RCD. An oven with a plug already requires this device.
How will you reconcile this?

Well, if it is permissible and the only risk is the N coming loose, I would take the risk - according to other threads (I linked) it is ok, but I understand that it is not recommended.

As I wrote earlier, I have equipment without plugs. "The oven and the hob do not have a cable with a plug, they are permanently connected!"

My RCD is for all common sockets (the second one is for lighting).
I also asked for information whether it is better to have the RCD converted into separate 1F RCDs per phase by an electrician due to the described possibility of N loss and major damage.

krzys-iek wrote:

My RCD is for all common sockets (the second one is for lighting).

Are you familiar with the content of standard 4-41? Probably not.
So you won`t do any favors with RCDs in socket circuits. This apparatus must be there, but probably not a four-track one.
RCD lighting circuits are not required, except for bathroom lighting. In this room, all circuits supplying power to the receivers placed in it must be protected by an RCD switch. This is where sheet 7-701 comes into play.
Therefore, any receiver that is permanently connected, i.e. without a socket or plug, does not require additional protection with an RCD.
Unless it was placed in the bathroom.

The device used as the main switch in your board is also a serious threat and had no right to be there.
Do you know why?

Shadowix wrote:

-A may catch fire due to a poor N connection from the 5x2.5 wire powering five and the board.

Don`t scare people - the forum is not for scaring people.
It certainly won`t catch fire for this reason.

Shadowix wrote:

due to poor N connection

Then you have to do it right.
That`s why it must be done by a professional - with experience.

krzys-iek wrote:

I drew the connection and in fact, if the box broke due to force N from the switchboard side, through the oven L3 will reach L1/L2 in the hob and there will be an interphase 400

The same applies to every WLZ 3f - including the one from the meter to the apartment.

It`s the same with RCD 3f. It has to be done right.
That`s how many people have RCD 3f for the entire installation and nothing gets damaged. Because they have it done well.

CYRUS2 wrote:

That`s how many people have RCD 3f for the entire installation and nothing gets damaged. Because they have it done well.

Because they do not apply one N and one PE to two separate circuits, i.e. they do not violate the provisions of §183 point 2 of the regulation of the Minister of Infrastructure on the technical conditions to be met by buildings and their location. Using one N wire for more than one circuit tends to end badly.

retrofood wrote:

Because they don`t use one N and one PE for two separate circuits

This is not from one phase.
These are not circuits, these are WLZ 3f.
There is no ban on the use of WLZ 3f in the regulations.

CYRUS2 wrote:

retrofood wrote:

Because they don`t use one N and one PE for two separate circuits

This is not from one phase.

Exactly. Different phases, different location of receivers one N cable (from the switchgear) and one PE cable.

PS. Different receivers from different phases, in different locations, is this one circuit for you?

retrofood wrote:

PS. Different receivers from different phases, in different locations, is this one circuit for you?

One three-phase circuit. The circuit starts with protection.
Likewise, one single-phase circuit does not have to end with one socket.

I may not support this solution 100%, but if the connections of neutral and protective conductors are secure, the risk will be the same as in the case of interruption of N on WLZ.

Induction cookers also usually require N. Nobody worries about breaking this wire anymore.

michu-michu wrote:

I may not support this solution 100%...

So I am against or even for it.

kkas12 wrote:

So I am against or even for it.

Let me put it this way. If doing otherwise would cause any problems, I would allow this solution.
If possible, I would designate a separate circuit for the oven.

Buddy, I`m afraid you`re not here to allow.
You can do whatever you want on your own or on your account because you are responsible for it and you sign it.
I wouldn`t do something like that, either for myself or for a client, regardless of the imaginary problems, because there are no problems, just laziness.
We are either electricians or "mycologists".

kkas12 wrote:

I wouldn`t do something like that for myself or for a client.

You write on the topic - not in general.
In this case, the client does it to himself - not to the client. Because I don`t want to break down the walls.
If he does it well, it will work well for him.

michu-michu wrote:

Induction cookers also usually require N. Nobody worries about breaking this wire anymore.

You wrote very well.
It`s the cooker itself, it may get damaged.
And none of my colleagues care.

michu-michu wrote:

Induction cookers also usually require N. Nobody worries about breaking this wire anymore.

Don`t screw up hungry pieces. What do you think is the point of insisting on running a separate cable (in accordance with the law) for each receiver? In your opinion, if both devices (both the stove and the cooker) are on fire, it will be better? Interesting reasoning for someone trying to pretend to be an electrician.

CYRUS2 wrote:

If he does it well, it will work well for him.

It cannot be done "right" in this way, because it will never be "right", but in a bungling way, with an additional risk. And don`t add any ideology here, because crap will always be trash, even if you wrap it in gold-plated paper and put ten inscriptions saying it is a miracle - honey.

I`m closing the topic, enough of this whining. As usual, tiles win over common sense, but hey, that`s how people make their beds, that`s how they will be.