Just seeing this discussion now... Just an FYI for you wrt how to monitor circuits with a limited number of CT clamps...
In the USA, with 240/120VAC single phase service, you can use a single CT to monitor a pair of circuits, so long as the CT is rated high enough to handle the pair of circuits. For example, a single 50A CT can be used to monitor a pair of 20A circuit breakers. You just have to be careful to run the pair of wires through the CT in such a way that they add to one another, instead of cancelling out each other. See an example here: CT Basics — IoTaWatt 02_03_20 documentation. I do this trick with my IoTaWatt to minimize the number of unmonitored loads in the house. While it does combine two independent circuits into a single reading, it still helps to pinpoint high use loads in the house.
As for one of the more interesting discoveries I have had using my IoTaWatt systems (one for my outdoor main panel, and one for my indoor subpanel), take a look at the following post over in the IoTaWatt forum.
Yikes, that is (or was) a dangerous situation. Samsung’s instructions are wrong. A neutral conductor (which is intended and sized as a current-carrying conductor) should NEVER be bonded to the grounding conductor, except at the service entrance point (normally at the main disconnect). Nowhere else, ever.
A 3-wire connection supplies 240 volts and a grounding conductor. The motor and the power supply for the electronics all run on 240 volts. I really doubt Samsung would have received UL or any other certification in order to sell the dryer (in the US, at least) if it was designed otherwise.
I hope you didn’t rewire your dryer. If you replaced it with a 4-wire cord, there should be nowhere to attach the neutral wire, so it doesn’t accomplish anything and it will not make it safer.
If there is a dedicated neutral terminal, then it probably was installed wrong to begin with and was supposed to have a 4-wire connection.
Whatever you do, do NOT attach the neutral (if there even is a neutral in the outlet box) to the dryer cabinet, never connect neutral and ground together, and never use a ground as a neutral if you only have 2 hots and a ground.
Cool! thanks for sharing! Out of curiosity, what happens if I get that wrong? Does it just “not work” or am I going to cook something? I like to know the worst case scenario before trying stuff like this. 110V tickles if I get it wrong. 220V not so much.
If you pass a pair of wires through the CT “incorrectly” they will simply cancel one another out, resulting in too low of a reading. No danger to you or the equipment.
No risk other than you already have being inside a panel. If the wires you are combining into one CT are from the same phase then they should both go through the CT in the same direction. If they are from opposing phases one wire has to be in the other direction.
I doubt any of these devices are UL approved though. As a general rule you have to use 600V insulation (thicker plastic jacket) on low voltage wires when they are comingled with line voltages. The units I have seen don’t have 600V wire to the CT. Not sure if they are ignoring the rule or that they are exempt in other parts of the world. Now 600V insulation might be overkill but somebody in codeland (NEC Article 300.3(C)(1)) thought it was a good idea.