AC Current Sensing Switch 0-200A Normally Closed Current Sensor Monitoring Relay (NC200)

Works perfectly. I put this in a double gang deep electrical box in our kitchen with a switch that disconnects the power to our crawl space sump pump. This detects current flow and turns on an indicator LED so I know when the pump is actually RUNNING (when the float switch detects water). A few years ago our old sump pump switch got stuck. That pump ran continuously for days. We found out when a smoke detector detected heavy smoke coming from the old pump - it almost burned our house down! This gives a lot of peace of mind since now I know when the pump is actually running.

Combined it with a 120V pilot lamp to see when my well pump is running and figured out a problem. It'll pay for itself in 2 weeks..

Upgrading a fixed speed poolpump and SWCG to a VS pump requires a means of removing power from the SWCG when the pump internal timer turns the pump off. Using the normally OPEN version to drive a power contactor/relay, controls power to the SWCG. In my application, L1 of the motor supply is passed through the sensor (red #12 wire in photo) to detect when the pump is off, which opens sensor output and relay, removing power from SWCG. The adjustment allows setting trip current for any pump speed. So far this has worked PERFECTLY.

I tried both the 30A and 50A normally-closed relays (NC30 & NC50), and both had relay contacts that never changed state. They just stayed open whether the current threshold had been met or not. Even when disconnected, even straight out of the box, the contact were open on the normally-closed relays. The LED lights would come on when current passed through, but the relay didn't change. So if you want a pretty light that comes on, hey great, but if you need relay action look at some other product.

This is a initial review, and more will come. There is a problem in this products web listing. I opened my package and used a VOM to be sure that it was a Normally Open relay contact. The website says it is a Normally Closed relay device.

Created a junction box with this current sensor to turn on an inline 6 inch fan whenever the microwave was powered on.

I’ll buy it again , it works from the very beginning. Description sucks but for smart people it will work

The media could not be loaded. Worked well for my needs, to turn one appliance off when another turned on. Be careful with the amperage, can only handle .3 amps on the terminals, needs to be used in conjunction with a contactor.