Combining CTs with splitter

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1

I have a question regarding this paragraph in the current transformer docs:

Two individual CTs can also be combined with a common headphone splitter and fed into a single IotaWatt input. When combining this way, both CTs must be the same model with an individual capacity sufficient to measure the combined capacity of the two circuit breakers.

I’m in the US (i.e. split phase power) and have a 50amp, 240v breaker for my car charger. The wires for it are such that I need to use two separate CTs to measure, one on each hot leg.

If I combine those CTs with a headphone splitter, do they each need to be 100amp or will 50amp CTs do?

2

They would need to be 100A, because the combined output would be measuring a total of up to 100A. You could use two 50A CTs if you use two inputs and combine the results with an IoTaWatt output.

Are you sure the charger uses a neutral wire? You might try attaching two CTs into two inputs and see if they prove to be identical.

3

Got it—docs are right, my understanding of the CTs is poor.

Great idea for checking whether there actually is a differential load, I’ll check when I get my new gear!

Thanks for the speedy reply.