Sonoff DualR3 2gang 2way wiring

[PZL0013]

Hi

Looking for some advice to what's hopefully a silly question.

I'm trying to install a Sonoff DualR3 to a 2gang 2way switch setup. Appreciate that Sonoff provides standard wiring as below:

Screenshot 2023-02-01 214311.png (66.83 KiB) Viewed 4336 times

However the actual 2gang 2way wiring is (likely) per below (and in any event not with just LIN to COM in the standard Sonoff wiring):

Screenshot 2023-02-01 214803.png (613.17 KiB) Viewed 4336 times

As such, I wired the DualR3 as below:

Screenshot 2023-02-01 214829.png (860.33 KiB) Viewed 4336 times

When this wiring is run, there's a smell of something burning in the DualR3 and I can see some sparks on the circuit board.

What could be going on?

[TD-er]

I think the Sonoff wiring you posted isn't correct.

See this one:


It looks like what you attempt to do is feed L2_in and power your lamp from L1_out
Thus then you're probably trying to draw current through the switch input or maybe causing sparks between L1_in and L2_in.
In the image I link, you can see the L1_in and L2_in are both connected

[PZL0013]

I got the image from https://sonoff.tech/product/diy-smart-switches/dualr3/

That said, Sonoff also mentioned in their instruction video (https://sonoff.tech/product-review/tuto ... nal-video/) that the two 2 LIN ports on the DualR3 are connected and one and the same. (I've also seen a demonstration of various videos on Youtube testing the DualR3 by plugging the LIN wire to either LIN port, so these seems to make sense). As such I think the two diagrams should be equivalent.

[TD-er]

If they are indeed connected internally, then that shouldn't matter.

I would open the Sonoff and see where it may look damaged.
Also, is it possible you swapped neutral and L?
I know it shouldn't matter, from a Sonoff point of view, but I also know some devices do act differently when Live and Neutral are swapped.

For example those 433 MHz CoCo devices had the low-voltage part of the board directly wired to the Neutral line.
Thus if you extended the antenna to get a better reception, it really mattered whether you swapped them.

[PZL0013]

Checked it a few times now, definitely didn't swap neutral and L

So another route I've taken is trying to trace the wiring to confirm how the switches are wired. The result of whether the light is on/off and current following at each terminal for each switch is as below:

Screenshot 2023-02-02 213504.png (627.59 KiB) Viewed 4277 times

Not sure if that's helpful but grateful for any insights

[TD-er]

Did you have a look inside the Sonoff to see where the smell/noise came from?

[PZL0013]

it's this bit here:

Screenshot 2023-02-03 084434.png (1.06 MiB) Viewed 4254 times

i have no idea what it means.

the DualR3 still works though (can connect to Wifi and operate switches through the app)

[PZL0013]

Got a consult and a glaring problem turns out the neutral wire I thought plugged in actually turns out to the neutral wire for another light

So I guess 2 possible ways forward, either:

1) get DualR3 to work without the neutral; or
2) try and pull the neutral to the switch

Ideas for 1)?

[Ath]

1) get DualR3 to work without the neutral; or

Ideas for 1)?

If you can find a Sonoff manual explaining how to use that unit without Neutral you're fine, but I assume 2) is the only solution (don't recall seeing any Sonoff units working without neutral)

[TD-er]

Got a consult and a glaring problem turns out the neutral wire I thought plugged in actually turns out to the neutral wire for another light
[...]

And when this was on another phase, you essentially fed 400V into the Sonoff.


I know some CoCo 433 MHz switches were said to be able to work without a neutral wire.
Those use way less power compared to an ESP, not even counting the current needed for operating a relais.
And still, those would not always work well as the 'leak-current' needed was highly depending on the type of consumer connected.
For example old fashioned tungsten light would work fine, but LEDs would either start flickering or glow very faintly, or both.

So nope, you won't be able to power the ESP without the neutral.

[PZL0013]

sigh, thanks for looking all

[PZL0013]

Got a consult and a glaring problem turns out the neutral wire I thought plugged in actually turns out to the neutral wire for another light
[...]

And when this was on another phase, you essentially fed 400V into the Sonoff.


I know some CoCo 433 MHz switches were said to be able to work without a neutral wire.
Those use way less power compared to an ESP, not even counting the current needed for operating a relais.
And still, those would not always work well as the 'leak-current' needed was highly depending on the type of consumer connected.
For example old fashioned tungsten light would work fine, but LEDs would either start flickering or glow very faintly, or both.

So nope, you won't be able to power the ESP without the neutral.

actually in that case i'm surprised the DualR3 is still working and hasn't blown up!

[TD-er]

Without knowing the exact schematics of the Sonoff, I think the switch input looks something like this:

SW --- 100k resistor ---- GPIO --- 1k resistor ---- GND

With probably some capacitor and some zener diode (or TVS) over the 1k resistor too.
However, with 230V you need at least 1 mm distance between the pads of the 100k resistor and more with 400V.
Given the size of the parts on your photo, I assume there were some sparks jumping over this resistor directly to the GND

I assume the internal GPIO pin of the ESP chip will no longer work reliable, as the components connected to it are no longer OK.

[bidrohini]

Did you check this vid? Was it of any help?
https://www.youtube.com/watch?app=desktop&v=CC_3vviE0YM

[PZL0013]

Thanks for the tip.

Yes have seen this before, it looks like the standard wiring. Unfortunately my problem is I actually don't have access to the neutral wire...