Creative wiring for CTs

Support
1

Now that I’ve had my IoTaWatt coming up on two years (can’t say enough positive things about it!), my initial guesses as to the “most useful” circuits to monitor has been off: my “everything else” IoTaWatt output (two mains added, minus the 11 circuits with CTs) is hiding some bigger than expected loads. So, I’ll be changing some CTs around. No problem there.

Then I starting thinking (always a dangerous thing)… I have a 100 A CT for the clothes dryer, and the washer is in that “everything else” calculated output. Can I wire up both the dryer and washer with the same 100 A CT and just call it “laundry”?

Problem is the dryer is 240 V and the washer 120 V. So, what if I looped one leg of the dryer through the CT twice (right now the CT contains one leg and the IoTaWatt doubles it) and one leg of the washer (paying attention to which phase the washer is on and which leg from the dryer I use)? Would that work?

Might I be missing something else that would make this a Bad Idea?

2

Dryers are usually a three-wire load. If that’s the case here, you should be running the two hot leads through that CT in opposite directions and unchecking double. The good news is that with that change, you can just add the washer hot lead, being careful to run it in the same direction as it’s cousin from the dryer.

3

You are correct…I was mis-remembering the range circuit instead.

Unfortunately, the washer circuit is on the opposite side of the panel, at least half the panel height away, so this isn’t going to be as easy as I thought without more serious rearranging of the circuit breakers. Harumph.

Good to know the method will work though, maybe for some other circuits (boiler and air handler, maybe).

4

It’s a long shot but you can pick up the neutral instead, just run it through the other way.