What size of CT for 30A double-pole breaker

I am about to purchase my first IoTaWatt bundle to install in a sub-panel. One of the circuits is a 30A, double-pole breaker for a gas dryer. Reading through the wiki, I understand I can use a single CT for this (with wires going in opposite directions).

My question is what size CT? Can I use a 50A CT, or do I need to go to a 100A CT?

Are you sure it’s a gas dryer? Usually, they only use 120V to run the tumbler motor. In any event, a 50A CT should be fine for that.

Thanks for the quick response. On closer inspection, it appears the circuit is empty. We do have a gas dryer and it looks like the electrician installed the breaker for future-proofing. Freed up 1 CT!

I do have an electric dryer and I had the same question. So I guess that realistically, the dryer doesn’t actually pull the full 30 amps, but does anyone know how many amps it might actually use. Just curious, because I bought 2x 50 amp CTs, thinking that I would need one for each pole, but then I saw the posts on here saying that you can run both wires through one CT (with one wire reversed).

I use one CT with one reversed, so the current shown is what the CT measures, which is the sum of the current in the two 120V legs. The actual 240V current is about half that, or a little less than 25A. The circuit has a double 30A breaker. I would not think any ordinary household dryer would be designed to use more than 25A per leg because most houses are wired with a 30A double breaker and #10 wire to handle a normal load of 80% or 25A.

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