AC Current Switch

I came across this item today while inspecting a 5 year old condo townhouse.
Does anyone know what it’s purpose is and why it would be required…never seen one before.

A current Trans Could be used to measure what the load is on that Circuit

This device senses current flowing through the wire in the loop and operates the switch contacts (2 black wires) to control another device.

Interesting. I’ve done many condo townhouses and never seen one before.
I can’t think of why this townhouse would require it.

I work in the CT industry and that is a AC current switch, simple thing. If it detects current passing through the hole in the donut over a set point, it either opens or closes the contacts.

Looks like it is looking at a circuit, then closing the contacts on another circuit (15 amps).
Any labeling on those 2 circuits?

Might be one circuit for a fridge and another for a microwave. I have seen something similar (albeit self contained) that shuts off the fridge circuit while the microwave is in use.

Just curious, why would you ever want to shut off the refrigerator?

I thought maybe I missed something, especially given a breaker trip curve.

A Loadmiser comes to mind which is an indication of a less than adequate service.

Some info at link below:

But it was a 100 Amp service for a small condo.

These can be used to turn on an inline dryer duct booster fan when the dryer is running or force a bathroom fan to be on whenever the bathroom light is on.
(The dryer load will need to be unbalanced to have enough neutral current to activate the device)

Its metering current for something… but I can only guess. Have you traced the black wires from the CT? What circuit is being monitored?

Given that this is in a condo I think that you’re correct. The white conductor appears to be a #10 and associated with the conductors on the 2-pole 30 amp circuit breaker. The switch is controlling the conductor from the 15 amp CB at the bottom.

No, I didn’t trace any wires.

Yes, I think it’s for the dryer duct fan. Thanks.

Guys, it could be a simple as detecting current to light an indicator light or a signal to some other piece of equipment.

Without tracing the wires its all a guess.

For inadequate service, like a dorm room, it prevents nuisance tripping if the fridge and microwave are either on the same circuit or on the same low amperage sub panel. But this being a full size panel, I agree that it may be a duct booster.

And this is just a current switch. In no way is it measuring current for metering.