120/240 V Power Shutoff Using Low Voltage Continuity

Maker, DIY
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1

I’m attempting to create a low voltage continuity switch which, when the low voltage circuit is “open”, 120V power is disconnected or interrupted to any devices which might be plugged into the device, using the power outlets. My question is “does something like this already exist on the market?” If so, can someone direct me to it…

Thanks,

Tom

2

Hi Tom, thanks for posting. To get some clarity, are you suggesting some type of power strip with 120VAC outlets, that would be operated by a relay or some other type of isolated low voltage circuit?

3

As a finished consumer product, I don’t recall anything the functions on basis of continuity per-se. In response to a signal yes there’s quite a few such products…

That said, the 1528-1777-ND could be used to achieve the desired effect without much hassle; simply plug a suitable wall wart into the unswitched outlet, and connect it to the control input through your contact closure.

4

Yes Zach….that is the idea.

My desire is to plug a 120V device into something like a power strip or a series of outlets. On the other “end”, there needs to be a way of sensing low voltage continuity (6v, 12v, 24v). when and if that low voltage continuity is broken, the device plugged into the 120V outlet, is shut off due to a lack of electrical voltage.

I was hoping there might be either a device already constructed for this purpose….or a populated circuit board which might provide contacts, etc to wire into a “project box”

I appreciate any advice or suggestions.

Tom

5

I have some ideas but before I spend too much time on it I need to make sure what it is you want.

Continuity testing is checking the resistance of a conductor to see if it is within a specified resistance (ohms) range that indicates a good conductor. I do not think this is what you want.

I believe what you want is a system that detects the presence of a voltage and turns off an AC outlet when the voltage is below a threshold, e.g. close to 0 volts.

Is that correct?

6

Correct

Tom

7

What is the difference between Part# 1528-1777-ND and Part# COM-14236-ND ?

Tom

8

So far as I can tell, about $4 in list price and the particular supplier through which the item was procured. The product itself appears to be identical.

At the present time, neither appears to be immediately available, presumably for covid-related reasons.

9

Adafruit says it has 38 units in stock for shipping today.