What's a simple way to create "OR" Logic so two 120V outlets can power one device?

Thread Starter

Umbra

Joined Oct 15, 2020
5
I have a 120v (~100W) exhaust fan and a temperature controlled outlet, a humidity controlled outlet, and a timer. I know they make devices that do 2/3rds of what I want to do here, but I'm monitoring two areas and I want the fan to activate if any one of the many devices activate so I really need a custom solution. Originally I was thinking about 120V relays, but I'm wondering if the simplest way might be to plug 12V wall wort/power adapters into the switches outlets on these devices and use something like this device (https://www.amazon.com/gp/product/B000LESCI2/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1)
which operates a 120V switch when 12V is applied on the trigger wires. Could I just splice the 12V trigger wires together or should I use diodes?

Is this a simple and safe way to go about this?

Thanks for any insight you might be able to provide.
 

jpanhalt

Joined Jan 18, 2008
10,525
Welcome to AAC.

A diagram of your plan would help immensely. However, a single pole double throw switch with center off is a simple option. For your relay, you probably want a both off option, hence your diagram. Another question is how you control the relay.
 

BobaMosfet

Joined Jul 1, 2009
1,234
I have a 120v (~100W) exhaust fan and a temperature controlled outlet, a humidity controlled outlet, and a timer. I know they make devices that do 2/3rds of what I want to do here, but I'm monitoring two areas and I want the fan to activate if any one of the many devices activate so I really need a custom solution. Originally I was thinking about 120V relays, but I'm wondering if the simplest way might be to plug 12V wall wort/power adapters into the switches outlets on these devices and use something like this device (https://www.amazon.com/gp/product/B000LESCI2/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1)
which operates a 120V switch when 12V is applied on the trigger wires. Could I just splice the 12V trigger wires together or should I use diodes?

Is this a simple and safe way to go about this?

Thanks for any insight you might be able to provide.
So, to clarify- you want a 120VAC @ 100W (about 0.833A) device to be powered if any/all of these trigger on:

temp
humidity
timer

...and to not power if all 3 of those are 'off'?
 

MrChips

Joined Oct 2, 2009
22,107
If all controllers are connected to the same AC phase I don't see why you couldn't just wire all outputs to the fan.
It would be the same as having multiple switches in parallel which is an OR function.
 

Hymie

Joined Mar 30, 2018
881
If you did that and pulled one of the plugs out of the wall socket, those plug pins would be Live at 120V~ something not recommended.
 

ronsimpson

Joined Oct 7, 2019
1,024
I have a box of small 110V ac relays. The relay coil is rated at 110vac. normally open contacts
The fan is powered from two wires labeled power.
Three devices can power the relays. If any 1,2 or 3 relays are closed the fan is on.
1602792221943.png
 

Thread Starter

Umbra

Joined Oct 15, 2020
5
Thank you for the responses. Sorry I haven't responded sooner. I'm only just getting some more time to tinker with this.
Here's a sketch of what I was thinking. I think it's obvious I'm only a hobbyist. I know this can be done with 120V AC only, but I figure tinkering with 12v is a little less zappy.

Forgot to include that all the Pre-Made Controlled 120V Grounded Outlets have basic 3 pronged grounded cords to plug into standard outlets. Nothing fancy coming in. Here's an example if needed: https://www.amazon.com/WILLHI-WH143...=1603209338&sprefix=120+thermo,aps,151&sr=8-5120v relay project-Model-1.pngscreenshot.jpg
 

Thread Starter

Umbra

Joined Oct 15, 2020
5
Just curious, how much wiring is involved between all these pre-made outlets?
They're plug and play.

They all function similar to this: https://www.amazon.com/dp/B00V4TJR00/ref=cm_sw_em_r_mt_dp_1rdKFbVZ31PQF

They plug into an outlet and provide an outlet to plug a device into. There's a sensor on a long wire that you place at the desired location. You set the box to turn the outlet on or off depending on what the sensor is reading.

My current plan is to use them to activate small 12V power supplies and use those to energize a relay that would control a 120V switch.
 

Thread Starter

Umbra

Joined Oct 15, 2020
5
I would say so since it would be mostly plug and play depending on the wiring required. If you use the 12 volt adaptors use diodes for isolation.
I posted a drawing beneath your post of what I was envisioning. Would I put a diode on each of the 12vdc positive wires and then join them up on the other side of the diode? And for the 12vdc negative wires do I need anything special there or can I just join them up as pictured?
 
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