hlk-pm01 wall switch only neutral

I would like to put a hlk-pm01 under a wall switch but I have only live not neutral.
How plug hlk-pm01 ?

Thank you

What is a hlk-pm01?
Why do you need to put it under a wall switch?

Tom.... :slight_smile:

oh sorry I have forgot the link.
hlk-pm01 is a transfomers 220v to 5v

I have make a pcb for turn on/off the light


I would like to put a hlk-pm01 under a wall switch but I have only live not neutral.

Do not mount anything like that behind a wall switch, inside the wall.

Put it in an insulated box, with fuse and proper leads and plug.
But do not connect it directly to the back of an outlet inside a wall.

It is not safe, I presume you are not an electrician.

Power supplies require ventilation and produce heat.

Tom.... :slight_smile:

Of course :slight_smile:
it's mount in this

but my question is how use the transformers without neutral

You connect the AC leads to Hot and Neutral, leave Gnd unconnected.
In the US that would be Black (hot) and White (neutral), Gnd is Green or bare copper wire.

I don't know what that corresponds to where you are.

Yes but in France, You have not neutral under switch
Example :

I would like put under the wall switch my PCB with the transfo

Guess you are out of luck then if all you have access to is the Hot lead.

You need hot and neutral... You need a voltage difference to get current/power.

...You will get a voltage across the switch when the switch is off (that's how a lighted switch works). But, you loose power when the switch is turned on. And, the voltage depends on the load resistance and the resistance of whatever you've connected across the switch. i.e. With a power supply like that, you might get 10% of the voltage across the light and 90% across the power supply and the light may glow dimly or flicker, etc. when the switch is off.

hlk-pm01 is a transfomers 220v to 5v

Thanks for the link, but that's a power supply, not a transformer. A transformer is a simple AC-to-AC component. A power supply has more components and usually puts-out DC.

So it’s not possible behind my wall switch ?

I would like use my PCB like this

You might have to relocate your project to a ceiling box, where you can grab a hot wire from the switch and a neutral from the light. That would work if this were wireless, and it has the added benefit of being turned off with the flip of the wallswitch.

I'm sorry but a wall cavity is not a power supply case, no matter what wall fitting you use.

Your installation will not be type/regulation approved, does your insurance company know you are doing this?

Tom.... :o

Ok, so for example I see this Dimmer and we can put in wall cavity. I don't understand why my installation will not be approved


That dimmer is designed and I presume approved for wall mounting.
It is designed to go in series with a power wire and does not need a separate Active and Neutral.

Your power supply needs Active and Neutral and is not approved to be fitted in a wall cavity.

Tom... :slight_smile:

Why is not appoved ?

Why is not appoved ?

Because nobody applied for a certificate of approval, I guess.
I would look into the MySensors framework to built a battery driven switch and put the main circuit somewhere else, where you have phase and neutral. Possibly even into the lamp itself.

You can show certificate is approval

“Meet UL, CE requirements”](Ultra-compact power module HLK-PM01)

For what? Mounting it in the wall? Powering children's toys? Or using it in a product that adds stuff like current fuse, thermal fuse, varistor, appropriate cable terminals ...?
It is very obvious that this is not an end user product, so I suspect the latter. Already the fact that you are facing bare pins gives that away.
Hint: There are projects around that use this particular part for an in-wall supply. They do the stuff mentioned above. If your insurance cares, is a different thing.

Mounting it in the wall and add fuse, thermal fuse, varistor

Those dimmers are designed to replace an existing switch to operate the lights remotely. I have installed a few here in the UK. You will need to supply a Line and Neutral to the unit and then the switch line goes to the lights. You can run a T&E from a light fitting to supply the neutral. Do NOT use the earth in place of the neutral to provide a voltage difference