Sonoff ZBMINI Extreme and T2 switch

Hello Everyone,
I’m a totally noob on smartswitches&co, so sorry if my question is silly.

I’ve seen that the ZBMINI Extreme can work without Neutral wire, which is perfect, since unfortunately in my home there is no neutral wiring.

Now I saw that I can “convert” my dumb light switch with this device.
My question is, can I replace my “dumb” light switch with a T1 or T2 (which requires Neutral), since the ZBMini Extreme should remove this issue?
If yes, how it’s the wiring?
Thanks a lot in advice.


There is information here:
You must also need a SONOFF Zigbee Bridge

On the link you sent me I cannot figure out IF it’s possible to connect a T1 switch.

Apart from that, does someone know how to wire the this old light socket to the ZBMINI Extreme ? (it has three cables, but no neutral wire):

It would be good to confirm which wire is which with a voltage meter, if you don’t feel confident with the current, hire an electrician.

Correct installations should comply with color standards and connection diagrams, but…

Check what your three wires are doing… One will be L (voltage phase). Be careful! when the fuse is on, this wire is live all the time!
The other two may be…

  1. Neutral
  2. Grounding
    Neutral/Ground and L transition to the second switch in the cascade model.

Unless it’s a multi-position switch?

Please remember that neutral N does not always mean ground PE. In old installations some people used N as PE. I saw horror installations where PE was connected to N… Theoretically, this is possible, but it also has its disadvantages.

In a wrongly constructed installation (inverted), a dangerous situation may occur: even though L is disconnected in the wall switch, the lamp/terminal socket is still energized!

If you have three cables, determine which one is for what, it is important!

Hello Morgan,
Thanks for the reply!
I will unmount the switch tomorrow, and check with a phase finder, which cables are carry current when light is off and when light is on, and I will get back to you.

But in the meantime, I have a photo of a light switch which I need help with too (sorry to bother!)
I have 3 light switches that can power on a single lamp.

Cable 1 = carry current only when light is powered on
Cable 2 = carry current only then light is powered on
Cable 3 = always carry current

How should I wire it?
Thank you in advance!

So I’m speculating that 3 is L, now check where 1 and 2 go.

Your installation may be of this type, although there are other possibilities.


You must draw a detailed diagram of this installation. What is connected to what and what the individual wires are responsible for and where each wire has its beginning and end.

First determine where the main AC L and N are. Then determine how the lamp(s) and non-smart switches are connected.

Without this, it may turn out that the selected Sonoff mounting point is wrong, in other words, it must be at the beginning and only from there the rest of the pasta will be added to the lamps and non-smart switches.
Here you have an example of a simple solution, one sonoff and one non-smart switch, one termination point (lighting), main (AC IN)…
Determine where your diagram starts, probably the box in the wall. There must be the first termination point of L and N somewhere…

In this model, the N wire coming from the main goes directly to the final termination point in the lamp.
The L wire from the main enters the sonoff at L-In. L-Out further supplies L with voltage to the lamp.

S1/S2 are for a regular switch.

You, however, need to determine the connection diagram for your installation, it’s hard for me to speculate… Because it is the most important thing to do it correctly. Either it won’t work or you’ll electrocute someone.

I can only guess… You say you don’t have N, N must be in the installation, but you may not have N in the switch boxes, which happens. But N must be at the end of the installation per point.
If you don’t actually have N in the switch boxes, you don’t have to think about it. Focus on L and connections to switches.

If you want, look at the socket on the wall or under the lamp mounting on the ceiling, there should be at least two wires, i.e. L N, correct installations should also have a third PE wire (grounding), but… Electrical installations are a nightmare, depending on the country and year of construction and who did it, situations vary dramatically and you can never assume that something is in accordance with the regulations.

For this reason, sometimes it is better to hire a licensed electrician.

If I have to call an eletrician, is will be too expensive, so I will return the whole thing and gg.

I don’t really know how to find out where the diagram starts.
I successfully mounted 2 sonoff in two rooms were only 2 wires were connected to the light switch.
But for the other 2 which I need… well, if it’s so complicate and I need an electrician, I’ll let it go, and return or throw away the bunch of things.

From how many places does the light turn on? If there are three wires and the switch is single and not double, that means the switch is a deviator switch.
The easiest way to use a deviator switch (double pole switch) is with the Sonoff Basic R4 as long as you have space in the light fixture.
Here is the topic: Using "Magic Switch Mode", the new resource of Sonoff Basic R4, with two 3-way Switches
Now I see you wrote that you have 3 switches, but I don’t see a picture of the third switch. It should have four wires. This switch is called a crossover.

Did you install MINI or T1/T2?

These non-smart switches are all three exactly the same and have three wires each?

You don’t have to get discouraged right away. :slight_smile:
I just don’t want to advise something that will burn your device or electrocute you…

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We can play guessing games, that’s why I wanted him to check the facts. :slight_smile:

I’m guessing that his installation in this part of the house is probably in this style… or not, because I’m not a clairvoyant. :slight_smile:

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Yes that should be the current scheme, but it will be difficult for him to do all three with the ZBMINI Extreme

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I doubt this particular model is the right one for the job. Especially if another smart wall switch is to be connected to it. It doesn’t make much sense…

If the reason for using this MINI is the lack of N, but at the same time our friend wants to connect T2 to this MINI, it will not work magically. This MINI can run without N, T2 must have N. Using this MINI will not magically make T2 not need N.

In such a situation, probably not Sonoff…

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I agree with that, but how about the Sonoff Basic R4. This model really impressed me as long as it really always works!

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Requires N-In I guess?

Both phase and neutral are required, but as shown in the photo, the relay must be installed in the light fixture.

I see a chance to get out of this situation if the OP is just willing to change the operating model a bit and spend $…

We take this mini and put it in the last box with the wall switch.

  1. Remove all three wall switches.
  2. Identify the L wire in the first box, the one closest to the main one
  3. Make a bridge/connect L with the next wire that goes to box 2
  4. In box 2, connect the incoming L to the wire going to box 3.
  5. In box 3, connect the L coming from box2 to the MINI L-In.
  6. In box 3, connect the wire going to the lamp as L to MINI L-Out.
  7. Secure unused wire ends in an appropriate manner.
  8. Buy three MOSE ZigBee Wireless Switch
  9. Attach to the wall.
  10. Perform the automation in some environment where pressing buttons can perform an ON/OFF action for the MINI.

It sounds complicated, but it isn’t! This way you can control the lamp from three points and control the lamp with interruptions L using the MINI

From an operational point of view, you would have the same thing as you have now, only instead of physical switches, you switch to ZigBee entirely, and in terms of wires, you are only interested in L continuity, the rest of the wires are not needed on such a model.
Of course, you should carefully consider a wall switch so that it can be easily paired with sonoff/ewelink.
Requirements: battery, zigbee or RF433, compatible with an ecosystem that supports it and sonoff.

Necessary purchases:
3 zigbee battery wall switches
2 wire connectors
4 insulated wire termination


In other words… we extend the entire L from main to mini L-In as one continuous line.
We are getting rid of wired wall switches.
We are moving to wireless and battery powered wall switches.

The End


Second thought…

You can also use zigbee wire-powered wall switches that don’t require N. Mose also has those…
The difference in the diagram will then be small…

You can use any ZigBee wall switches in this installation model, provided that they are officially prepared to work without N.

Something like that…

Can Sonoff T2 do something like this… the documentation doesn’t mention anything about N, you would need to verify whether T2 is able to work properly without N, then it could be used.

Instead of a 1-1 pass-through connector, you will use something like this. You divide the L coming into the box into two L. One goes to the wall switch without N, the other goes to box2 as before, etc…

To sum up, we don’t want to control the light via L in a wall switches, we do it via zigbee.
L at the wall switches is only used to power the device.
MINI is responsible for light control via L.

Another option is not to use the MINI at all. Just connect L in box3 directly to the third wall switch.

In this model, the first two switches control the light only via zigbee. The third one can do it physically via L1 control.

Of course, you need to have some kind of ZigBee hub/bridge and something to automate these behaviors.

From the automation perspective it will look something like this…
The first two switches send actions to the system, which tells switch #3 to turn on the light.
This model is a master and two slaves.

And I think that this solution, if you don’t want a battery-powered wall switch, will be the best solution for you.

In any case, you have options to choose from on how to resolve your situation. :slight_smile:

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You gave a very detailed explanation, I hope the person understands. But I would do it with the Sonoff Basic R4 because the same switches can be used.

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This is also an option worth considering by the OP. :slight_smile:

There are several options to decide what suits him best. That’s why I wanted to know his electrical installation topology from the very beginning, otherwise I can only throw ideas on the wall and see what sticks.

It would probably be possible to present something more, but we are already completely leaving the scope of Sonoff… So there is probably no point in taking these discussions this far. :slight_smile:

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