Mechanical Switch on an outlet ??????

Ok I love asking these questions because I have searched all over and have made no headway on the subject, so I've returned once again to all the experts here at plcs.net to try and get an answer.
I am looking for a way to know if someone is plugged into a 120vac outlet with a basic switch contact switching 12vdc. The big problem is that a current switch is too expensive for the project and a current transmitter is even more expensive. I would like to get a wall outlet with a mechanical switch inside it to switch 12vdc to feed into a 12vdc PLC input, so I know when someone has a device plugged into the outlet.


Thank you in advance to all the guru's,

Dave

I have seen what you are looking for, but long ago so I dont remember the details. Basicly it was a contact closure that was activated by the ground prong on the plug. The contact could be wired in series with the Hot feed so ungrounded plugs wont work. So there's hope for your search.

Let me get this strait
You want to determine if someone is plugging into a 120 V outlet.
You want to "measure / detect" this using a PLC.
You want a combination switch outlet in a single device.

Somewhere in the world there may be one. Here in USA I believe you can got to Home Depot and get one.

I do not think NEC (USA) "approves" 12 V and 120V in same box unless there is a barrier between two. So you cannot do it with sigle device and be NEC compliant.

Am curious why do you want to do this?
Dan Bentler.

Look at Relay In a Box (RIB), they have self contained current sensors and switches.

leitmotif said:

I do not think NEC (USA) "approves" 12 V and 120V in same box unless there is a barrier between two. So you cannot do it with sigle device and be NEC compliant.
Dan Bentler.

Click to expand...

actually, the NEC states you can mix different voltages in conduits/wireways/junction boxes without using dividers as long as all conductors share the same insulation type

Now, Dave didn't state that he wanted to know if the device, whose cord is plugged into the outlet, is drawing power, just that it's plugged in. How about a small photoeye send/recieve unit looking across the outlet. If something is plugged it it breaks the beam.

If Dave does want to know if the unit is drawing power, I suggest something like what is shown in the attached PDF.

One day a customer asked for a quick and dirty way to detect whether a benchtop machine was working or not and turn on a light when it finished the cycle. It had to work without connecting directly into the machine thereby voiding the warranty.

I came up with this. Its quick and dirty and cheap, so feel free to use it.

stasis said:

actually, the NEC states you can mix different voltages in conduits/wireways/junction boxes without using dividers as long as all conductors share the same insulation type

Click to expand...

I think you are right. I think I had that class 1 and 2 stuff in mind. I GOTTTA get disciplined and study and memorize that book.

Dan

leitmotif said:

I think you are right. I think I had that class 1 and 2 stuff in mind. I GOTTTA get disciplined and study and memorize that book.
Dan

Click to expand...

You don't need to memorize it, you just need to know where to look in the book.