I have just installed a pair of attic exhaust fans and am using a pair of Levitton Decora switches. These are the type that has a neon lamp to indicate when the switch is off. In this case, I had hoped that when the load was off (thermostatically controlled fans, mechanical thermostat) that the neon light would be off as well.
As it turns out, with the load on, the neon was quite visible if I opened the switch. Now it is night, the fans are off (confirmed with my clamp on ammeter) and the neon lights are on, bright enough to be seen with the garage light on.
Is this due to capacitance of the fan runs (40 and 100 feet)?
I had hoped they would turn off with the load. I am adding a timer to the circuit so that I can restrict the runtime. The switches were for turning off in the winter and the lights were to indicate if the temperature warranted turning the fan on. Now I don't think I can tell except the way I have been doing it with the temporary lash up, using a clamp on ammeter.
The switches have only a line, load and ground terminals, no return to neutral, so I expect the neon is in parallel with the switch contacts.
Any solutions?
I have thought this through a bit more. I found on the web, a claim that
14-2 Romex has 21 pf per foot capacitance. I have 12-2 Romex. For the sake of argument, 12-2 has 25 pf/ft. If so I have 2500 pf at the load end of the switch. If I calculate the Xc (at 60 Hz) it appears to be a load of 1.06 meg ohms. This being the case, I could plug a 100K resistor in the back stab openings of the switch and have a 1/10 divider. The neon light should go out. The resistor should see only 140 milliwatts at
120 volts with a short circuit. I might try a 1 meg resistor first to see if that works. I will probably use a 2 watt resistor so the leads are physically substantial.
Does this sound like a good approach?