Hi Andrew:

It's been my experience that the split type current transformers only work well 
for currents near their max rating.  For small currents the error increases. 
It sort of says that on the CR Magnetics web page, but not clearly.

I used a toroid type for just this reason and put it in the main breaker panel 
with the burden resistor and some series resistors as a safety precaution, i.e. 
the output is a low voltage into a high impedance D/A so the resistors will 
normally have no effect, but if line voltage appeared on the wires it would be 
current limited.

Using a seismometer type display on the computer screen was quite interesting. 
  I.e. to get the maximum time resolution vertical lines are drawn one pixel 
wide and separated by maybe 10 pixels.  24 hours of data of zero current is a 
whole bunch of straight vertical lines.

With this setup you can see when a current starts and stops.  Also since most 
things draw different currents and are used at different times of day you can 
pretty much see what's being used.  For example you can tell if it's a bathroom 
light or the refrigerator light that caused the current late at night.

-- 
Have Fun,

Brooke Clarke
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