Range has 240V 2 phase with a Neutral. How to wire CT help

Hi All,

I just ordered my unit and still waiting on it. I bought 2 CT at 100A for the mains and 12 50A for everything else.

My kitchen Range Uses what I believe is a 240V 2 Phase with Neutral configuration. ( One Red, Black, White) How would I go about putting a CT sensor? Both Red and Black wires?On on each or 1 for both wires? Do I have to double it up in the interface?

You have two options here.

For maximum accuracy, the way to go would be to put a 50A CT around each of the red and black wires. Those wires are carrying up to 50A each, so you don’t want to pass both of them through one 50A CT.

Or, if you’re okay with a little inaccuracy and would rather use one of those two CTs for something else, you could put one 50A CT around either the red or black wire, then double it. The reason this mostly works out is that all the major loads in a range, the heating elements, will be running on 240V, so this measurement method will be perfectly accurate for them. The 120V loads are usually only the oven light and maybe some control circuitry, which is almost negligible compared to the large draw of the heating elements, and so won’t affect things too much.

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Tomatotree:

Thanks so much that makes perfect sense. I will decide on which method as soon as I see what I will be controlling. I have 12 CTs to play with so hopefully I will be able to do it the right way with 2.

Then I suppose in the setup you tell the device to add those 2 CT together in order to report a single reading figure right?

Thanks again for your thorough answer.

With no intention to hijack my first question I have another question: can you run 2 X 120V Hots (Black wires) in a single CT? Would you need to change the direction of one of the wires through the CT?

thanks

You can configure an output as an addition of both CTs. I do this on mine. My range draws ~10 watts idle (to power the display/etc) and pulls on one leg for the convection fan and cooldown fan. I’d definitely recommend doing two CTs vs one doubled.

My output looks like: **Range_Total** Watts = Range_30 + Range_32

Screenshot_2020-07-31_20-19-09

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If you haven’t read the split-phase documentation, that may help.

To answer the question directly, any wires from even rows in your panel can be bundled together in a single CT, and same for odd rows. If you are mixing even and odd rows, one or the other must pass through in the opposite direction. If you think about it, that’s the rule that we are using for the 240V three-wire breakers.

Regarding your question about combining two CTs from the range, you would define an output that adds the two together.

Edit: @deviant beat me to it.