Starting an extractor from more than one source

[richie4236]

We have a power shower in our family bathroom which is triggered and powered from the lighting circuit (switched and permanent live).

My problem is that our bathroom has a large east-facing window, which means there's no reason to turn the light on in the morning during spring/summer/autumn, and so the fan doesn't run. It's easy enough to flip the light on and off again, but I have two teenage children......so obviously that's a lot of effort and they don't bother, and the room gets really damp.

Is there a simple way I can trigger the fan from multiple sources? The shower is wired to an isolator in the airing cupboard, and then directly back to the CU in the garage. The light fitting is somewhere in the middle of the upstairs circuit.

My understanding (possibly incorrect) is that I can't do anything which would effectively bridge the lighting circuit and the ring, so not sure if what I want to do is even possible? Advice appreciated.

 

[JohnW2]

We have a power shower in our family bathroom which is triggered and powered from the lighting circuit (switched and permanent live).

I presume from what you say that you want the fan to be triggered by the power shower as well as by the lights?

Is there a simple way I can trigger the fan from multiple sources? The shower is wired to an isolator in the airing cupboard, and then directly back to the CU in the garage. The light fitting is somewhere in the middle of the upstairs circuit. .... My understanding (possibly incorrect) is that I can't do anything which would effectively bridge the lighting circuit and the ring, so not sure if what I want to do is even possible? Advice appreciated.

Your understanding is essentially correct. If you want to control an item which is 'powered'; by one circuit by 'power' from a different circuit, then you need some sort of 'relay', so that it is always the same circuit that supplies the something with power, but that that power can be switched on/off (via a relay) with power from a different circuit - so that "never the 'twain circuits will meet"

Kind Regards, John

 

[jj4091]

Could you put a dawn to dusk sensor in line wth the live to the light
https://www.google.com/search?q=+da...gGAZAGCJIHBDMzLjGgB7aaAQ&sclient=gws-wiz-serp
and a motion sensor in the supply side if the kids really can't be bothered to switch anything on

Google Search

 

[ebee]

Relays are excellent and you could have one circuit (example one trigger or sensor) controlling another, that would mean the wiring of two or more circuits in one location which might not be desirable for safety reasons though.

You could put some kind of link, say optical or radio or Wifi/bluetooth etc between the two so in your case all the power to run the extractor is taken solely from the extractor circuit but another circuit that is electrically isolated from it could trigger the extractor to run, that would be the safest option.
The world is your lobster.

 

[AndyPRK]

Decent humidity sensor ?

 

[hllns]

There are also bathroom fans with a PIR sensor, as with a humidity sensor unit it could just be a simple fan swap then, nothing complicated.

 

[Taylortwocities]

As @jj4091 has suggested, simply fit a PIR motion sensor to the existing fan, then the fan can turn on every time someone enters the room.
This could be wired independently of the the light.
If you fancy a multi-function fan, as suggested by @hllns then the Vent Axia Svara is pretty comprehensive!

Lo-Carbon Svara White | Vent-Axia

www.vent-axia.com

 

[robinbanks]

Or have the motion sensor do the fan and the light, then you don't have to touch a string/switch with hands you've just washed, knowing full well that a reasonable percentage of the time that switch is touched by unwashed hands before/after business

 

[SUNRAY]

We have a power shower in our family bathroom which is triggered and powered from the lighting circuit (switched and permanent live).

My problem is that our bathroom has a large east-facing window, which means there's no reason to turn the light on in the morning during spring/summer/autumn, and so the fan doesn't run. It's easy enough to flip the light on and off again, but I have two teenage children......so obviously that's a lot of effort and they don't bother, and the room gets really damp.

Is there a simple way I can trigger the fan from multiple sources? The shower is wired to an isolator in the airing cupboard, and then directly back to the CU in the garage. The light fitting is somewhere in the middle of the upstairs circuit.

My understanding (possibly incorrect) is that I can't do anything which would effectively bridge the lighting circuit and the ring, so not sure if what I want to do is even possible? Advice appreciated.

Curent transformer switch on the power shower to trigger the fan?

Such as: https://www.aliexpress.com/item/1005004503711502.html?

 

[JohnW2]

Curent transformer switch on the power shower to trigger the fan?

I suppose that qualifies, at least conceptually, as the "some sort of relay" that I mentioned.

 

[ebee]

I suppose that qualifies, at least conceptually, as the "some sort of relay" that I mentioned.

yes indeed, another good option

 

[SUNRAY]

I suppose that qualifies, at least conceptually, as the "some sort of relay" that I mentioned.

indeed and advatageously only interferes with the shower equipment by requiring a disconnexion, threading through and reconnexion if there is a suitable space