Does anybody know a wifi switch with wet contacts

Hi folks,

To start with: a happy new year for all of you :champagne: :clinking_glasses:

Tried to install my first Shelly 1 yesterday into my electricity closet, but the wiring diagram was a bit different as I had expected:


When you start wiring this device, the 2 black dots will need to become Wago connectors. Which I don't really like, because I find it quite messy and more difficult afterwards to figure out how it works. Others may think different about this, but that is my personal opinion...

Seems that the I-O pins are called a dry contact. Didn't do my homework good enough when I bought this device.

In fact I assume I need a WIFI controlled wet contactact switch (preferrable DIN-rail), to simplify my wiring to something like this:


Does anybody know such devices that can do this? I have been looking e.g. at Shelly but I don't "think" they offer anything like that. But I can be mistaken!


I have some of these. They are (primarily) aimed at light fittings where there is live + neutral and the switch wire in the ceiling rose. In other words, they are ideal for single device items (like a light fixture)

What is your application? Are you expecting to "cut" the power at source (e.g. at -or- just outside of your consumer unit (DB / distribution board))?

Regarding dry/wet. Apart from these Shelly 1 being single pole, as you have continuous power at the point of installation, you can wire this (shelly 1) to be both powered and to switch the output. But if you do need double pole switching, the 2PM has 2 contacts: Shelly Plus 2PM | Shelly Store UK | Smart Home Automation

Hey Steve,
Very simple application. I have some outdoor wall outlets where I have plugged in christmas lights. I would like to power on/off all these wall outlets via Node-RED, to (de)activate the lights remotely. So indeed yes like you say, cut off the power.

Yes indeed, but I had planned to buy afterwards a din-rail for the Shelly 1 switches at amazon:

Then I dont understand your issue with the Shelly 1. You can certainly wire them to "cut power" - the only "issue" is they are single pole. But this is no different to how many lights are switched on/off (in that the neutral is constant but the live is switched)

Yes you are right that it is single pole, and perhaps I should use double pole.

Yes indeed I can wire it to cut of power, as explained in the diagram of my first post. The problem is that I need to install a couple of wago connectors:


As said above, for a lot of folks this doesn't matter. But I think it is quite messy compared to the other circuits in my electricity closet. With a wet-contact switch this isn't necessary. Then the cabling is much more straightforward, and easier to understand. But that is all personal taste...

You would need a device with 2 dry contacts to do what you wish (cut live and neutral). some sonoff devices do that (can be flashed with tasmota).
I would just put a double pole contactor on your din rail and use the shelly 1 to break the live to the contactor, using its dry contact.


for silent switching, I think you can also find DP versions.

No Wago's will be abused in the making of this circuit.

FWIW The dry contact allows for isolation between the driver signal and the device. i.e. you could switch a 230V ac load with 24V dc.

As your outlets are outdoors, you might want to switch both Live and Neutral (I would). For that application, or switching higher currents, personally, I would put in a Contactor, or use a 2 Pole switch depending upon room and load. This would prevent any Neutral-Earth faults especially should there be water ingress.

(E1CID beat me to it!)

To poke my nose in here, you say that you have plugged your lights into a socket. If the socket is a standard socket outlet the relay / contactor - whatever - must be rated at the same current handling capacity as the MCB that the circuit is connected to, which in the UK would probably be 32A.

One reason for this is because you may only have lights plugged in at the moment, but in the summer you may have something a lot more powerful connected.

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Hi @E1cid,
that would indeed be a workaround. But so weird that you would need to combine two devices to accomplish this. Had expected that at least once manufacturer would build a single device that would offer this kind of functionality...

Yes indeed. I did buy the Shelly 1 without doing my homework well. Normally I discuss here on Discourse first before I buy something, but had a lack of time...

Whell the wall outlets are installed just below the roof, where the christmas lights are installed. So they are installed there solely for that purpose.

But I must admit that few weeks ago I plugged another device into such an outlet, because I quickly wanted to do something at that location. So yes you are right. Need to take that into account...

If you want to mount it on a DIN rail, take a look at the Shelly Pro line.
For instance Shelly Pro 1
With this, you can connect via LAN, Wifi or Bluetooth.

This look nice but not cheap -

But it does do 4 outputs !!
But not "wet" contacts :disappointed_relieved:

Cant you simply pack it all away in a din rail enclosure?

Or if you know someone with a 3D printer: Printables

This might do most of what you want, including DIN rail mounting, I think.

In general, the Sonoff range does not offer dry contacts, while the Shelly does. Dry contacts are considered an advantage in terms of flexibility, but I understand your preference.

@jw_te_r, @smcgann99,
Yes indeed the Shelly pro devices are looking very decent when you want a din-rail solution like me. But like you also have seen, they also have dry contacts. So unfortunately then I still would need to connect wires with wago connectors...

that is indeed a very useful case. Never seen it during my searches. Will keep it in the back of my head.

Yes indeed I see that the Sonoff relays have wet contacts. Here is another one, which can also be din-rail mounted.

Now going to ask a stupid question: I see all over the place people installing Tasmoto firmware on their Sonoff devices. Is that really necessary. Just want to turn the switch on or off from Node-RED via wifi. Can I just do that with such a Tasmoto relay?

If you want to use off-the-shelf products without using wago connectors you could combine some kind of interfacerelais with a Shelly pro. I have done a similar thing in the past, but I must say I like @Steve-Mcl 's solution. Its relatively elegant and a lot cheaper, if you have access to a 3D printer.

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You can control the Sonoff switches with un-modified software from NR using this node, but I think you have to run through an account on their server. There may be a way to set up a local server, but I haven't looked into it.

I mentioned the four-channel unit because you were interested in switching both the neutral and the load.

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This doesn't have power monitoring, not sure if you needed it ?

I have used a few of these around the house, flashing is easy enough and then no cloud needed plus you do get full control of your devices. I often modify them to do extra things using the spare GPIOs

Q. How many circuits do you want to switch in total ?

@drmibell 's SONOFF 4CH R3 seems like a good option for you needs

Ah un unflashed device needs cloud access. Good that you mention it. Since my body develops high allergic reactions to that. Must be an abnormality somewhere in my DNA :wink:


You only need one wago, because the neutral coming from the outdoor socket stays connected where it already is (at the N-rail) and you just use another blue wire to connect the shelly's N to that N-rail too.

Only for the Shelly-L and Shelly-I connections you might need a wago to split the one wire coming from the circuit breaker into two.

If you use a shelly 2.5 you don't need any wago at all because it has only L and no I connection (so it can be called a "wet contact" [actually even two of them, so you can switch 2 sockets independently with only one shelly]).

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