Need some help picking CTs for US bundle

Chr · December 19, 2021, 9:38pm

I would appreciate some help picking CTs for the US bundle. My panel is 200A and I have a (top left breaker) 220V for a utility pump that is the more important one to start with.

Here’s a picture of my panel:

Thanks for help

overeasy · December 19, 2021, 10:15pm

It’s a 200A panel, so you should use 200A mains. I don’t see any breakers with capacity greater than 40A so you should be able to use 50A CTs for branch circuits. If you plan to run more than one conductor through one CT, you’ll need to assess the expected total current and size appropriately. As always, two-wire 240V requires one CT and three-wire requires two or running both conductors through one CT in opposite directions.

Chr · December 20, 2021, 1:51am

Thank you! I’m a little bit confused about the mains. The 200A black split-core is what I think I need, correct? Not the white one.

overeasy · December 20, 2021, 2:23am

Either one, there’s plenty of room.

Chr · December 20, 2021, 2:32am

Thanks again. Do you think I need 1 or 2 for main? Is there a way to figure out if I have split-phase 120V/240V? I’m pretty sure I have 2 wire 240 for the utility pump. Does that mean I have split-phase?

frogmore · December 20, 2021, 2:41am

Normally, a pump will be a 240V device, so it only needs a single CT. You then tell IotaWatt to double the value.