My application has a 120vac, 7 amp appliance (device A) that I need to put a relay on to switch power to it. A second device (device B) will determine whether or not to switch the power, and this second device has a LV class II circuit that is either open or closed, depending on the status of this second device – i.e., if the second device’s reservoir is full of water, the LV class II circuit will be open, and if the reservoir is not full it will be closed – this LV class II circuit has no power. I will add a SPST EMR to the system to switch device A, but I need a way to connect device B’s LV class II circuit to the EMR so that it will control (and provide power to) the coil of the EMR.


Suggestions?

 

You explanation is a little confusing.
Can you post a diagram of what you have and what you want it to do?