Several Sonoff dual R3s in the house that are used in lighting flashing when activating the electric water heater

I don’t know how to speak English, I’m using Google Translate, so there may be errors in what I want to write, but I hope you understand…

I have never had any problems installing these devices. So in a new house I am unhappy with the result. The lights flash quickly while I use the electric water heater. I’ve tried everything I could think of to solve it, I increased the thickness of the electrical cables and it didn’t solve it. I changed the RST electrical phase of the appliances to another that is not the same as the one that turns on the heater, which didn’t help either. I replaced the Sonoffs with the ones in my current house, it’s still the same. I don’t know what else to do, can you help me?

Devices used in automation, SONOFF DUAL R3.

Invite an electrician with measuring instruments. A professional inspection is needed. Remote advice on a forum? Not a good idea.

Here in Brazil, especially in my city, it is still difficult to find the use of these automation devices. There are no professionals who work with this, I am a professional and a Civil Engineer and I have the necessary equipment, I have extensive knowledge with electrical and electronics… However, I have not yet been able to identify any problems… I have already tried, as I mentioned, There are several ways to get rid of the flashes, but without success, and any help is welcome, but if it doesn’t help, please don’t get in the way.

I guess your wires are in the same channel… It is enough for flashing. Put something like it between N and L just before your lamp.

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As you have traced the problem to the water heater operation and are looking for mains borne noise or voltage spikes have you considered the possibility of a faulty thermostat? My father worked for GPO tracing radio interference for 25 years in domestic situations and faulty thermostats were a big problem. I also worked for British Telecom as an engineer. I think it’s preferable to find the fault condition rather than just suppress it if possible.
One point to consider if using capacitors across 220v or 240v supply is that the peak voltage is rms voltage x 1.414 volts. The capacitor must be able to withstand peak voltage of the supply.(For 240v operation a capacitor of 440v rating is commonly chosen)


I don’t know if I was clear but the electric heater I meant is a shower (electric shower)… Here in Brazil we use an electric shower to take a shower, there is no thermostat, it doesn’t work like a conventional heater that stores hot water in a boiler, the electric shower is for instant use (it heats the water after activating the valve)… But I don’t understand that this is the cause of the problem because in 6 other houses where I installed the equipment works normally, the voltage spike never caused any failure (here 99% of homes use instant electric showers). Could using the capacitor help in this case? Another thing that I thought might be interfering is that the house is located right next to the city’s power station, with high voltage cables (16kV) running about 15 meters from the house, if this is the cause, should I try use a rectifier filter or whatever, I have no idea.

We still don’t know what kind of home automation devices you have and how this relates to the eWeLink forum. Maybe you can find a moment and give a hint? For now, we only know that you have a flow-through, inline water heater.

I don’t know if when editing the text to translate I ended up accidentally deleting it, I apologize, there’s no way to help with my problem if you have no idea what I’m using… But then, in my homes I use the Sonoff dual R3, I’ve always liked the devices and that’s why I always chose it for projects. I always install the devices close to the lamps (to facilitate maintenance if necessary).

The fact that I am a civil engineer and have some test equipment, does not change the fact that here where I live, it is rare for someone who has good knowledge or who can help with these devices, so I thought of joining the forums where thousands of other users can have an idea. and help me.

I consulted an electrician who I know about your problem. His opinion is that starting the heater causes a momentary drop in the power supply, and this in turn affects the relay in your Sonoff Ddual R3. Especially if the power supply to your house is via an overhead line, and you live at a distance from the distribution point.
Based on a sparse description, it is impossible to pinpoint how to remedy this. The electrician says that the use of some kind of stabiliser in the lighting circuit will prevent flares. There is no certainty, but if you have the possibility, it is worth a try.

Your video, is it not showing the shower turned on and then the shower room light flashes? That seems quite relevant. As you have other lights controlled by dual R3 devices, are they flashing also? Assuming that the R3 has logs, is this recorded? I prefer a moving coil meter when looking for voltage fluctuations.
I have ordered a dual R3 device from Amazon to try and see if loading the voltage supply on our country overhead wires theory can be proved.

Olá. Podes escrever em português? Não se percebe muito bem o problema na tradução da Google

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Sim, claro. Pode ser a variedade portuguesa ou prefere a brasileira?

É igual ou me dá igual :blush: A língua é a mesma.

Eu apostaria na sugestão de Aleksey Kuimov colocando o condensador (capacitor). É o que se faz quando há "ruídos na linha.
(I would bet on Aleksey Kuimov’s suggestion by placing the condenser (capacitor). This is what you do when there is “noise” on the line.)

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Ok. Vou descrever tudo o que até agora sei sobre meu problema. A casa está situada a cerca de 500 metros da estação de fornecimento de energia da cidade (descartando a hipótese de problema na distribuição da energia), porém tenho dúvidas que a rede aérea de alta tensão que passa muito próximo a casa possa estar causando algum ruído. A casa possui 23 aparelhos Sonoff dual R3 e 2 Sonoff mini R2. Os aparelhos funcionam tranquilamente enquanto não é ligado o chuveiro elétrico. Quando é acionado o chuveiro, são 4 locais que acabam piscando, porém com mais intensidade é o lustre da sala de estar e a luz do lavabo (restroom, toilet), sendo que são de aparelhos diferentes e são de outro quadro de comando (disjuntores). A casa possui 2 pavimentos, cada pavimento possui um disjuntor individual para tomadas, chuveiros, iluminação e ar condicionado. Para quem entende de corrente elétrica, tem dois chuveiros em funcionamento um utiliza a rede L1 e L2 (220v), outro utiliza a rede L2 e L3 (220v), a iluminação está na rede L3 (ao qual o chuveiro é menos utilizado) e neutro (127v) , porém no uso de qualquer um dos chuveiros ele pisca. A rede da casa toda foi ampliada com cabos de 25mm² o que consegue suportar com tranquilidade 89a (amperes). O chuveiro possui 7500 watts o que dá aproximadamente 35a, mesmo com outros aparelhos ligados não acredito que passe de 60a em uso ao mesmo tempo. Já tentei trocar a rede L1, L2 e L3 para iluminação e a que menos interfere é a L3,
já troquei os aparelhos Sonoff dual R3 por outro de outra casa que não da problema e não adiantou. Em todas as outras casas o sistema é basicamente o mesmo (chuveiro elétrico e aparelhos Sonoff Dual R3) mas nenhuma tem este problema de piscar. Quando ocorre os Flashes é como se estivesse pressionando o botão e o LOG do aparelho registra Ligado e Desligado no mesmo instante. Não sei mais o que fazer, vou tentar um Capacitor como mencionou txe2defender e aleksey.kuimov. Desde já agradeço a todos que estão se esforçando para tentar me ajudar. Vou tentar gravar um video mostrando o chuveiro ligado e os flashes, portanto o vídeo pode ser longo pois as vezes demora um pouquinho para começar.

Este LOG é do ambiente Lavabo (restroom, toilet) que está posicionado no andar térreo e ligado na rede Linha L3. Já os 2 chuveiros estão localizados no segundo andar da residência e estavam ligados ao mesmo tempo, utilizando a linha L1+L2 e L2+L3 porém de outro quadro de disjuntores. Acontece mesmo utilizando somente 1 chuveiro (L1+L2) com menos frequência, mas acontece.

The explanation may be surprisingly simple. Perhaps the activation of this particular heater triggers a pulse induced in the switch circuit, which is interpreted by R3 logic as a change? Investigate this possibility.

I am puzzled why your neutral is at 127v? I’ve only ever seen neutral at 0v and bonded to earth. The phase being 220v (or 240v UK and Ireland) measured to earth 0v,

Noise on cables can be heard using an LM386 audio amp and telephone pickup coil. (Switches operating cleanly, microwave noise. ZBmini has a high pitched tone and mains hum when idle, when operated changes to mains hum only. No hum or tone is radiated down the switch leads.

I’m waiting for my dual R3 to arrive, the road was blocked today and we had no postal delivery.
I will test that out when it arrives.

In Brazil there is no standard voltage. Most federative units use 127 V electricity, but some other states are on 220 V. Some homes have both 127 V and 220 V power supplies for their lighting.
BTW, in the UK and Ireland you have 230 V, as it is in most European countries. In 2003, the voltage used throughout the continent of Europe was set at 230V and 50 Hz. Before this, it was officially 220V in Europe and 240V in the UK.

That’s interesting about 127v, it looked to me from the way it was written that neutral was floating above 0v.
As I understand things in uk and Ireland in the 1950s there was a mixture of voltages throughout England. Around the 60s it was standardised @ 240v. During EU membership it was harmonised to be compatible with Europe and it ranged between 240v -15% and 240v +5%.

It stayed at 240v nothing changed but everything had to be capable of working between those limits throughout the EU.

Here in Ireland I measure from 235 to 245.