Cable Cross-Section Calculation for 22 kW, 25m Length & Required Protection Measures

I am asking you to calculate the cable cross-section of 22 kW and the length of 25 meters, and what protection is needed for this?
Thanks in advance.

What at the end of this cable ...

For power: P = 22kW and length l = 25m, cos (phi) = 0.8, Un = 400V:
- current flowing: 39.69A,
- voltage drop: 1.5% - for a cross-section of 4mm? Cu.

Da 4mm? the long-term load capacity is as per tables 40A.
I would suggest a cross-section of at least 6mm? - load reserve. Long-term load capacity (for 6mm? then it will be 51A.

The load capacity of cables is also influenced by the way they are arranged.

Calculations: http://www.prs.pl/page690.html

What is the function of this cable? Power supply for switchgear, motor / equipment?
Is the security supposed to be delayed, immediate? The nature of the device is decisive for this.

It is an OTK - 2000P / E 22.5 kW air supply unit

And please give me which protection is better:
-delayed
-immediate
How many Amps and what difference

Thanks in advance

Differential 30mA / 40A protection S303 B40A

Thank you very much for your help

pajaczek1967 wrote:

It is an air supply unit OTK - 2000P / E 22.5 KW

Quote:

There is a 22.5 kW heater and two 290W fans. Current consumption 35.1A. Practically a resistor.

arekd555 wrote:

Differential 30mA / 40A protection S303 B40A

There is something wrong for me :idea:

Pg = 22.5 kW
Pw = 2x ~ 0.3kW = 0.6kW
P = Pg + Pw >>> 23.1kW

And we have this:
P = 23.1 kW
U = 400V

Long-term load current:
for cos (phi) = 0.9 >>> I = 37.05A ??? -OKAY
for cos (phi) = 0.8 >>> I = 41.68A - Something is wrong! The S303 B40A will continue to energize and power reliability will be degraded.

Depending on the temperature factors (heating of the device) for cos (phi) = 0.9, i.e. for the current I = 37.05A, the protection may activate unnecessarily.

We're balancing here on the verge of loadability, buddy arekd555 that's why I would suggest:
RCD - P304 63A 30mA
Miniature circuit breaker - S303 B63

Who knows what will be connected to this control panel in the future? Any drivers / modules / displays?

As for the security itself, there is one more question:
Is this protection supposed to protect the cable and the control panel or the control panel is already secured and you want to protect the cable?
I am asking because the topic is:

pajaczek1967 wrote:

I am asking you to calculate the cable cross-section of 22kw and the length of 25 meters and what protection is needed for this.

Hello. I agree, you can use the typoshift up, but I took into account the max power. 22.5kW. The S303 B63A and RDC 63A / 30mA protection is also correct, but too high for the resistive load. Say ...

I agree
Theoretically cos? for heaters = 1 but only if we test the heater itself (the "resistor" with the appropriate parameters, of course), because practically all the supplied energy consumed by a given receiver is released in the form of heat.

In reality, however, it is a bit different. Depending on the technological structure of a given device and its advancement, in addition to the heating element, there are also other elements such as various types of controllers (sensors / elements / control elements / relays), executive devices stabilizing the heating process, so that the set value, e.g. max. has not exceeded the set tolerance, and they also consume some energy.
In this case, cos (phi)

We have the cable and the circuit protection ...

What if the short-circuit loop impedance of the switchgear from which the heater will be powered is, for example, 0.02? and there is a short circuit right behind the protections you wrote about?

I would love to hear you answer.

And I have a question for "pseudo electricians" on this topic. Why do you use "differential" as a cure for all evil? This control panel requires only a fused power supply without a "differential".

DTR of the device:
Link

Minimum protection 3x35A delayed - use 40A

MuNiO wrote:

And I have a question for "pseudo electricians" on this topic. Why do you use differentials as a cure for all evil? This control panel requires only a fused power supply without a "differential".

And in the DTR it says:

Quote:

"... The ventilation device must be plugged into a working (grounded) socket, which complies with all electrical safety requirements ..."

geguś wrote:

JohnySpZOO wrote:

I would love to hear you answer.

You have replied to yourself and others in previous posts. For all evil RCD .

I refer my friend to the topic RCD- a panacea for all evil or necessity?

MuNiO wrote:

And I have a question for "pseudo electricians" on this topic. Why do you use "differential" as a cure for all evil? This control panel requires only a fused power supply without a "differential".

DTR of the device:
Link

retrofood wrote:

And in the DTR it says:

Quote:

"... The ventilation device must be plugged into a working (grounded) socket that meets all electrical safety requirements ..."

MuNiO >>> Page no. 4 (top) Apparently my colleague cannot read with understanding. I recommend that you familiarize yourself with the topic given above.

JohnySpZOO wrote:

retrofood wrote:

And in the DTR it says:

Quote:

"... The ventilation device must be plugged into a working (grounded) socket that meets all electrical safety requirements ..."

Page no. 4 (top) Apparently my colleague cannot read with understanding. I recommend that you familiarize yourself with the topic given above.

I don't know if it's for me. They taught me to read, so I quoted what I read.

Added after 35 [seconds]:

geguś wrote:

retrofood wrote:

MuNiO wrote:

And I have a question for "pseudo electricians" on this topic. Why do you use "differential" as a cure for all evil? This control panel requires only a fused power supply without a "differential".

And in the DTR it says:

Quote:

"... The ventilation device must be plugged into a working (grounded) socket that meets all electrical safety requirements ..."

Does this control unit have a cable with a plug installed by the manufacturer? Because I understand that a seventy-two-kilo air handling unit is a portable device. I guessed?

That is the question!!!

(although those 72 kilos are a bit too much ... )

geguś wrote:

retrofood wrote:

I don't know if it's for me.

I am asking in general. Who knows, let him answer. They also taught me to read and taught me to understand the text I was reading. If it is to be connected via a socket / plug, then there is nothing to debate. The rated current of the device is 35A, which disqualifies the 32A socket. The only thing left is a minimum of 63A. As we know, sockets are general-purpose circuits, so the protection of such a circuit is 63A. And the matter is solved.

And if someone comes to think and power this device without a socket and plug, then one can debate.

I just wanted to draw your attention to it, only because Kol. MuNiO referred to the DTR. The spread of the parameters of these heaters is very extensive.

retrofood wrote:

I don't know if it's for me. They taught me to read, so I quoted what I read.

I corrected - see my post above. I also sent a message regarding the improvement of the statement to PW.
The answer concerned the speech of a colleague MuNiO.