I am having a serious issue with my mechanical ventilation system.

I have replaced the old one and bought a new one from the same brand and with the connection (dammm Perilex!).

I thought that the device will work right away but not... thats where the problem started.

I have tried almost all the combinations on perilex plug (while keeping earth and neutral in place all the time) but couldn’t found a working(!) solution with my 3 way switch.

Finally I connected all the wires as mentioned on product manual to the plug. enter image description here

The ventilator is not working on neither or the speeds dictated by the 3 way switch. I have then tried to measure the voltage on different switch positions.

Here is what I found ... enter image description here

I was expecting some 0v in respective positions... i.e. 0V for L2, If we select Speed 1 (S1), or 0V for L1 If we select Speed 2 (S2)... but neither of them goes 0v as I always have some voltage on each.

May be thats the reason... may be switch is broken or I am missing a very fundamental point which might be all about how that is being setup in the electric box.

This is current connections of the plug (I couldn't take the fuse down as It cuts the lights .. at least for now. .. )

In summary I have one blue, one green, two black and one brown wires. I have tired make them all visible for everyone with arrows in colours.

enter image description here

enter image description here

Finally this is how my main electric box looks like. Number 8 is the fuse of that plug (as well as almost all the light sources, plugs in the kitchen and some more out power outlets).

I was expecting a bit different fuse (combined one or so...) as I believe (not sure anything anymore though) that is 3 phase

enter image description here

What do you think ?

The ventilation system is working ... it is not broken .. as the dealer checked it again ..

by the these are the inputs on the board. enter image description here and the supplied schematics from the manual.

enter image description here

And this is the current connection of the 3 way switch as well as the connection diagram from the manufacturer

enter image description here

enter image description here

I am more or less a handy guy and would like to fix this by my own but that kind of output is unique in Netherlands (where I moved), I have no experience on these and I am really exhausted.

Any help will be appreciated !

thank you

UPDATE : I started to see very strange behaviour... or I am getting mad. I have plugged the fan to the same outlet and observed that the fan starts to run .. increases the speed for 3-4 sec.. and stops .. then starts and stops. goes on and on .. ...

If I check the voltages (the switch is on highest setting) L1 is 232V stable, L2 is not stable and around 150s.. and L3 is 230 but gets lower and lower by the speed increases until 160V s where the fan stops. When the fan stops, It jumps to 220v-230v and gradually decreases as an opposite of the fan speed.

It is almost mid night in here.. may be something behaves different on the grid compare to day hours when I don't get 220-230v even for a moment. ...

Something weird is going on..

  • A picture of your actual wiring showing both the wires in the plug and to the receptacle would be beneficial. Feel free to edit your post to include it.
    – FreeMan
    Nov 2, 2021 at 15:31
  • 1
    Sure.. just did that! hope it helps
    – atoprak
    Nov 2, 2021 at 16:01
  • Are the voltage measurements done with the ventilator plugged in? If so, unplug it and measure at the socket alone.
    – TooTea
    Nov 3, 2021 at 15:12
  • @TooTea I did both... the one with ventilator plugin is down in the comments below. Just unplugged and checked again Speed1 : L1>135 L2>145 L3>200 Speed2 : L1>180 L2>230 L3>207 Speed3 : L1>230 L2>180 L3>204 are the current readings.
    – atoprak
    Nov 3, 2021 at 15:31

1 Answer 1


Don't be fooled by Perilex, this isn't 3-phase.

Unlike the 'Muricans, who seem to require a dozen or two of different plugs, one for each conceivable purpose, Dutch engineers have come up with the one plug to rule them all, the Perilex. Wisely realizing that there's plenty of situations that call for a mains-voltage grounded plug with more than two working contacts, they have found several different ways to wire a Perilex receptacle/plug:

  • As a three-phase socket for motors (one neutral + all three phases), protected by a 3-phase breaker (krachtgroep)

  • As a socket for two single-phase circuits for cooktopsw (two neutrals + two phase conductors), protected by a dual breaker (that fornuisgroep you have at the top left of your breaker panel). These two circuits can be fed from the same phase or from two different phases depending on the way your house is wired. The point is that the cooktop doesn't need to care.

  • As a single-phase socket for central ventilation (one neutral + one phase + two control wires for selecting the speed), protected by an ordinary single breaker.

If you look at the wiring diagram in your question, there's a single "L" (phase) wire entering from the bottom, connected to the "L3" contact which supplies power to the ventilation system. "L1" and "L2" are just control signals telling the ventilation system on what speed to run.

Now, the confusing voltages you measured are due to the L1/L2 contacts being left disconnected (floating) when not in use. Your multimeter is likely just picking up stray voltage induced onto the floating wires. (Or flowing back from the ventilation system if you measured this with it connected.)

There's one 230 V entry in each L1 and L2 column, which shows that your speed selector switch is working properly (apart from the fact that it looks like the "L" and "M" speeds are swapped).

The trouble is likely in the connection of the L3 contact. That's supposed to provide 230 V to power the system, but it doesn't seem to be doing that. You'll need to investigate a bit to figure out what is going on here. If you have a contact voltage tester (one that has a small light in it that lights up when you touch a live wire), try that on L3. There might be a loose connection somewhere or some other issue.

  • This is correct. Low and Medium speeds are not achieved by delivering lower voltages. They are achieved by signaling on different wires. Your best bet is to read the manual and wiring diagrams that came with your new unit and follow the instructions carefully. If it doesn't work, modify your question so that it shows those instructions and diagrams, how you interpreted them to wire your installation, and what works or doesn't work accordingly.
    – jay613
    Nov 3, 2021 at 12:53
  • I don't have the same respect as you do for the engineers who designed to use extra high voltage wires for signaling. If they did it on the existing wires that would be way cool. But if they demand extra wires to be run, why not separate the signalling and use low voltage wires and switches? In fact a lot of these units have that ALSO.
    – jay613
    Nov 3, 2021 at 12:58
  • @TooTea thanks for the clarifications and details. you are right about non 230V measurements as they are always floating. If they are 230V and they are rock solid. I did some additional measurements but not from the plug but from the input of the ventilation system. (added the image on the original post) The numbers are changed this time. Now what I am seeing is L1 L2 L3 S1 106 110 150 S2 155 230 155 S3 230 155 155 Yes, I don't see 230 on L3 (brown in my case) at any time. What would be the reason for this ? Is switching the cable can change this or it is not healthy at all?
    – atoprak
    Nov 3, 2021 at 13:43
  • There are four relevant wires in your last photo. White, Black, Brown, Blue. One of them is Live. In the switch that one should be open, or connected to ONE of the others. You haven't given us enough info to know which wire is L, L2, L3. If I guess that brown is L and blue is N, then the switch must either connect brown to black or white, or leave it open. The wires must be connected to the switch so that the switch does that. It's not obvious how to get that right ... the four connections look similar and symmetric. Use the instructions, measure continuity not voltage.
    – jay613
    Nov 3, 2021 at 14:07
  • Remember this isn't just a Perilex socket. There is a switch attached to it, that shorts together certain terminals. The orientation of that switch with respect to the colors of the four wires, matters. We can't guess this.
    – jay613
    Nov 3, 2021 at 14:13

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