"RogerN" wrote in message
m...
Thanks all for a lot of good ideas. The reason for my over
engineered project using an Arduino microcontroller is to have a
programmable thermostat with programmable current sensing and
hysteresis, plus time delays, etc. Also, there are arduino
libraries for communicating X-10 over the power lines. I'm not sure
if X-10 modules will be powerful enough for my heaters but I can use
them to switch on a solid state relay.

If I can use the current sensing relay idea, or the comparator idea,
I can have my current sensing on digital input pins, saving some
analog pins for temperature sensing.

My current idea is have the current transformers and Arduino at the
breaker box. When the current goes too high (or temperature
setpoint), the Arduino sends an X-10 command to shut off the heater
on that circuit.
In short, it will be a multi-zone programmable thermostat that tries
to prevent breaker tripping.

This project came about because of the price of propane, I want to
have an alternative if the propane runs out while the price is
outrageous.

RogerN

Don't forget to allow for the faults the Arduino can cause, like
shutting off all the heat.
jsw