Using a relay on a switched live model ceiling fan

[bobby2021]

Hello,

I am planning to add a wifi switch to the ceiling fan in the bathroom so that it's a bit smarter.

The switch in question is a Shelly 1 Relay. The ceiling fan is a switched fan that operates when the light is on, and then starts it's own timer countdown once the light is off. The light is being replaced with a Hue unit, so the power will always be on - this would cause the fan to run all the time, hence wanting to add the relay. We are also planning to tie the relay to humidity sensors.

The goal is to have the fan running whenever the relay is on, and off as soon as the relay is off.

If it were a plain 'always on' fan, I know how I would connect this:

But obviously this doesn't work for this model because its looking for the switched current in order to start.

So, what is the best way to do this? Connect it as above and to the existing switched wire? (This will always be on) Or is there a better way?

Thanks in advance.

 

[flameport]

Connect L & SL together on the fan, it will then run when power is applied and stop when not.

Other than the next to useless humidity sensor, how do you intend to control the fan?

 

[bobby2021]

Thanks!

So like this?

To answer your question and elaborate a bit:

There is a Zigbee humidity sensor in the bathroom and motion sensor, this feeds into Home Assistant, this controls the Shelly the relay can be controlled by any connected device: Google Home, Zigbee wall switch, phones, NodeRED etc.

The reason it has to be this way is because the Hue light requires the power to always be on. Without re-wiring, this would leave the fan on. The fan only has a timer, so using this approach it now has a humidistat and the lights can illuminate automatically on motion, and turn off if we forget. We have found the humidity sensor to be quite reliable in letting us know if the bathroom will get mouldy but up until now the sensor has just sent a push notification to our phones to open a window. Now it can activate the fan too. It’s more for clearing the fog after a hot shower, not making sure the room is bone dry.

 

[bobby2021]

Thanks that's worked a treat