What type of sounds does Splitvolt Splitter Switch make?

It is normal for you to hear a clicking noise from the unit when the dryer is started or stopped.  The device is sensing the power draw of the dryer, and disconnecting power to the EV socket.

It is also normal to hear a quiet hum coming from the unit whenever it is powered on. You shouldn’t be able to hear this hum if you are 20 feet away. Sometimes humming can get louder or quieter over time. Turning the break on/off a few times can often help the contactor’s contacts re-seat, and get quieter.

Both of these noises are generated from the contactor within, and are normal.

In rare situations, the humming sound could travel through the wall, one can use a Vibration Isolation Washer to absorb the vibration.