I want to measure the power needed to heat my house in the states. I have a geothermal heat pump on a 40 amp 240v circuit and an air handler blower with backup resistance heat on a 60 amp 240v circuit.
Do I place a CT on each leg of both circuits?
Thanks in advance.
You can do - but it might not be necessary. It depends on how much power the 120 V part of each takes - which is probably only the control electronics, but it might include the blower motor - and crucially if the inaccuracy of not measuring those is acceptable to you. I can’t guess how much motor power is needed to shift 14 kW of heat, but I guess it’s about 1 kW so it could easily be a 240 V motor. If the motor’s rating is given, or you can see the rating plate, this will help.
The other question is - do you want the power/energy of each separately, or is a combined value good enough? If it is, can you get the cables for both through the same c.t? If you can, that will automatically sum the two currents.
Perhaps not.
I have two 10 kW central heat systems. One air handler motor uses 320 W when it runs,
the other air handler uses 160 W. The system with the 160 W motor is much newer than the system with the 320 W motor.
I thought you’d have a better knowledge of that than me.
Thanks! I placed the CT over both legs of the circuit. Appreciate the help on this.