3 phase elements

Hi. I have the 3200W heating elements in my setup today, but need to upgrade. Im looking to buy the 3 phase 5500W heating elements. But I see that this comes as a 5 wire setup. From my electrician I have been told that I can upgrade my fuses to 3 phase 16A that will give me 16A x 230V x 1,73 = 6366 W. However this will only be 4 wires 3 phase since I dont have space for more than 4 wires.

So the question is if there is any way for me to use the 3 phase heating elements with 4 wires or if there is any way to transform 4 wire to 5 wire?

Thanks for any response.

Where do you live? And what kind of power do you have coming out of the wall?

In most places in Europe, 3-phase is 230V between each phase and neutral and 380V between phases.
The elements are used in a star configuration, so each resistor is between a phase and neutral.


Some places do have a 400V phase to phase voltage, but no neutral. In that case neutral can be left floating, because when the currents from the 3 resistors are balanced, the current through neutral is zero.
The floating midpoint is like a virtual β€˜zero’ and the resistors still get 230V each.

If your phase-to-phase voltage is 230V, which is the case in some places in Norway for example, only then you can use a delta configuration.

The calculation made by your electrician is not correct. A 3-phase connection has 16A for each phase and can supply 230V * 16A * 3 = 11040W in total.

Where do you not have the space for 5 wires?

Thanks for the quick reply.
Im actually located in Norway.
I tried to google, and it seems to me that the calculations using √3 is correct. But I am not an expert. But maybe this is not that important, since I only need 5500W elements.

How do you calculate 3-phase wattage?
AC three phase amps to watts calculation formula

  1. P(W) = √3 Γ— PF Γ— I(A) Γ— VL-L(V) So watts are equal to square root of 3 times power factor PF times amps times volts:
  2. watt = √3 Γ— PF Γ— amp Γ— volt. or.
  3. W = √3 Γ— PF Γ— A Γ— V. Example. …
  4. P = √3 Γ— 0.8 Γ— 3A Γ— 110V = 457W. Watts calculation with line to neutral voltage.

So the 3 phases will be connected without the netutral in delta configuration?
I have 16mm electrical flexible pipes and will not be able to fit more than 4x2,5mm2 wires in this.
Is it possible to add a picture how to use 4 wires for the 5 connections of the 3 phase elements?

Hello fellow-norwegian!

This is how I did it! 230v 3 phase 5,5kw

In most of Europe, we have 400V phase-to-phase and 230V phase-to-neutral.

To calculate the total power based on the phase-to-neutral voltage:
230V * 16A * 3 = 11040W
To calculate the total power based on the phase-to-phase voltage:
400V / sqrt(3) * 16A * 3 = 11085W

Note that 230V = 400V / sqrt(3), with a small rounding error.

Where you live, 230V is the phase-to-phase voltage. The phase to neutral voltage (if you have a neutral) is 230V / sqrt(3) = 133V. So for the total power based on the phase-to-phase, you are using formula 2.

Because your phase-to-phase voltage, also called line voltage, is lower, you should connect the elements in delta as shown by @Oltid_youtube. Note that the yellow-green wire is connected to the screw in the flange and not to the middle row.

Sweet. Thanks million both to @Elco and @Oltid_youtube for your valuable input. This is what I needed.


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