I think you mean “Shield_CT1234_Voltage”.
That should certainly be calculating the powers for all 4 inputs, provided you’ve not disabled them at line 57 or so.
Are the values you see small, or a solid zero?
OK, that proves the Arduino and input is working - that’s noise you’re seeing.
So I’d check the c.t.'s themselves: tip to sleeve with the c.t. off the cable and unplugged, you should read about 100 Ω.
If you have an a.c. milliamps range on your meter, you should see 50 mA per 100 A of primary current, measuring tip - sleeve.
Have you soldered the sockets on the correct (= non-component) side of the pcb? I assume so as one channel works, but it’s worth a mention.
One problem we used to have was, the input sockets were extremely stiff, and hard to get the plug fully home. You should see no sleeve between the body of the plug and the body of the socket.
Sounds like including a note with the shield kit that points out the correct side of the board to install the jacks on might help with this issue. Kept simple and direct to the point, attached to the board itself, say with tape, would (hopefully) make it easy to spot.
Robert’s (not another one!) experience having previously successfully assembled one Shield just emphasises how conditioned we are to putting all the components on one side of the board. It’s a pity that the socket pins are symmetrical and it’s possible to fit it on the “right” (but incorrect) side.
@Gwil’s recently changed the words for the build guide in Resources. I think that even a printed note in the kit could be worthwhile. I’ve no idea how many Shield kits have been sold and assembled, but we’ve seen and know about a good half-dozen assembled wrongly like this - there could have been many more.
If the pcb is ever revised, a warning on the wrong side legend might also help.
I’m not sure what more can be suggested, short of printing the pictures from here (just above “Hardware Setup Instructions”) and packing that with the kit.
Speed and excitement was part of the issue I guess
My suggestion would be if there is no detriment then if you can solder a wire in place to fix is to make the PCB have this channel printed there also. Then it could go on either side
I enjoy soldering so I don’t mind doing a 3rd board.