How Can I Shut Off 110V House Current with a Moisture Detector?

Thread Starter


Joined Mar 28, 2007
Hello All,

I'd like to connect a moisture alarm to the outlet that my well pump is plugged into so that current to the well pump is cut off when moisture is detected. Has anyone heard of a device that does this? If not, would it be easiest to modify a ready-made alarm (with a relay, perhaps) or build something from scratch? I would appreciate any info at all!




Joined Nov 1, 2006
You can try the first idea & use the output to the motorized or solenoid shut off valve to drive a contactor with a normally closed contact in its stead to disable the pump motor when it energizes. Contact rating must be at least 125% of motor full load current. You need to do a little homework first like find out what the output voltage & current to the shut off valve is then locate a contactor that'll work & decide if it's worth the expense.


Joined May 16, 2005
You want something called a "shunt trip breaker." In addition to functioning like any other breaker, it can be tripped remotely by closing a set of external contacts - usually with a relay. You can shut off a lot of amps with a much smaller control current. Remote trip coils for shunt trip breakers usually operate on 24V.