Fuse, Characteristic L: Understanding 20A Automatic Home Fuses and Safe Purchasing Options

Hello
I have to buy a 20A home fuse, automatic but the only characteristics I found were L what exactly does it mean? Can I buy one without fear or look for some other?
Regards

I add that :
L - securing wires and cables.
Markings concerned fuses.
Regards ŁP

The PN-74 / E-93002 standard introduced three types of characteristics of circuit-breakers marked with the letters L, U and K.

L and U were designed to protect installation cables and receivers connected to it against short-circuits and overloads. The U characteristic was used when higher currents could occur in the installation when switching receivers (motors, etc.)
K were designed to protect motors against the effects of overloads and against short-circuits, taking into account starting currents.

The PN-90 / E-93002 standard introduced the characteristics of B, C and D. However, there was a problem with the proper replacement of L, U and K switches with B, C and D switches. trigger work areas.

From the time-current characteristics, we can read the multiplication factor needed to check the effectiveness of the SWZ.
K factor for the characteristic:
L is 5.25
U is 12
K is 10
B is 5
C is 10
D is 20

I do not have money to replace it with a newer one, so for now, such a fuse is enough for me
It is supposed to be a kitchen security, with a newer Amica refrigerator, a gas stove with an electric oven, and a microwave with a grill. 20A should be enough? Should I take 25A, of course I take into account that I will have to replace the cables with thicker ones.
Regards

arti13 wrote:

Quote:

I do not have money to replace with newer ones, so for now, such a fuse is enough for me

Quote:

20A should be enough? Should I take 25A, of course I take into account that I will have to replace the cables with thicker ones.

You cannot currently afford to change the security from automatic screwdriver to redundant installation switches ("eski"), and you have "money" to clean the walls and replace the wires :?:

Quote:

Can I buy one without fear or look for some other?

If it is a general purpose socket protection then you should look for another- smaller!
The L characteristic of this security is approximately B (treated as such).

No no, you didn't understand me. I know that you have to break the walls, etc., but I will not do it for now. I told Mom that a separate installation would be needed for the stove, but she heard from a friend that replacing the fuse would be enough and impossible to translate. So can I get a 20A fuse or bigger?

Show mom what she writes on the plug or socket - and she writes 16A / 250V. On the socket from the inside.
So 16A protection (if the wires used have a cross-section of 2.5 Cu).

20A protection with single-phase power supply makes it possible to connect receivers with a total power of approx. 4600W.
However, the question remains whether this protection is properly selected for your installation.

A small correction to what was written in the column remix_I

Quote:

From the time-current characteristics, we can read the multiplication factor needed to check the effectiveness of the SWZ.
K factor for the characteristic:
L is 5.25

For the author, this is not important information, but
Redundant circuit breaker in accordance with PN / E-93002 (switching off the circuit breaker in time t

Hello,
I refresh the topic because I have a similar problem. In an apartment in a block of flats, in the event of a short circuit, apart from the overcurrent switch in the box (B16 for socket and B10 for lighting circuits), the L25 fuse on the cage pops out.
Somewhere on the forum, one of his fellow users wrote that the L and B characteristics are comparable. Therefore, I have doubts whether the solution used in my apartment does not conflict with the principle of security selectivity. Could someone please dispel my doubts?

Besides, more practically: what can I do to run less to the main fuse on the cage in the event of a short circuit? In the box in the apartment I have a residual current circuit breaker and then circuit breakers for individual circuits. Does inserting the 25A main switch there just before the anti-shock lamp make sense and comply with the art? Please reply.

You are sure that the permissible current of that cage was 25A
I had the same thing, but someone put 20A on my cage.
Regards

arti13 wrote:

You are sure that the permissible current of that cage was 25A

In this box, all of them have 25A, but most of them are typical fuse-links in ceramic housings and there are probably two Urmets, such as mine (L25A). So I'm sure!

Hello!

The multiplicities are more than comparable. They are almost identical.
So forget about selectivity.

Quote:

Does it make sense to insert the 25A main switch there just before the shock lamp ...

It doesn't make any sense. After all, the one in the corridor must remain so.

The solution is to use a selective overcurrent circuit breaker.

kkas12 wrote:

The solution is to use a selective overcurrent circuit breaker.

But the selective switch, one that is devilishly expensive, and two that I would have to install it on the staircase (if I understand the principle of operation correctly), where there is only room for screwdrivers on the board. Are selective screwdrivers?

The idea that I threw up in the previous post, with the installation of an additional fuse in front of the anti-electric shock, would just provide selectivity within the apartment. The L25A fuse on the cage would of course remain, but it would never pop out in the event of a short circuit (or overload) because the main switch added to the box would have popped out earlier. The only question is whether there are 25A circuit breakers with characteristics that enable faster shutdown in short-circuit than the B characteristics?

Hello!

Quote:

The idea that I threw up in the previous post, with the installation of an additional fuse in front of the anti-electric shock, would just provide selectivity within the apartment. The L25A fuse on the cage would of course remain, but it would never pop out in the event of a short circuit (or overload) because the main switch added to the box would have popped out earlier.

It is a misconception, because the value of the fault loop impedance will cause all circuit breakers to trip at practically the same time.

Quote:

The only question is whether there are 25A circuit breakers with characteristics that enable faster shutdown in short-circuit than the B characteristics?

Another wrong idea. You are to delay the activation of the pre-meter protection and not accelerate the activation of the overload switches installed in the switchgear.

Quote:

But the selective switch, one that is devilishly expensive, and two that I would have to install it on the staircase (if I understand the principle of operation correctly), where there is only room for screwdrivers on the board. Are selective screwdrivers?

The price is the price and you can't beat that.
Use a fuse, but you have to take into account that if it blows, you will have to break the seal.
You must pay for it.

kkas12 wrote:

Use a fuse

This is a pretty good sounding idea! At least until the renovation is completed, short circuits will not happen later
Because as I understand correctly, this fuse will not work in the event of a short circuit in the circuits protected by switches B16 and B10, but only in the event of a line overload with a current exceeding 25A. That's right?

gem58 wrote:

Because as I understand correctly, this fuse will not work in the event of a short circuit in the circuits protected by switches B16 and B10, but only in the event of a line overload with a current exceeding 25A. That's right?

If you buy a delayed one, it is unlikely to work, because the tripping time of overcurrent circuit breakers is much faster (of course with a sufficiently high short-circuit current), therefore only the circuit with a short circuit will be disconnected.

Thank you very much for your helpful answers and best regards