Measuring 3 phase power current

AI Thread Summary
To measure current in 3-phase cables, it's important to understand that each live wire must be clamped individually to obtain accurate readings, as the currents in the live wires do not cancel each other out like in single-phase systems. Using a multimeter to measure the RMS current in each line and the return line can provide insights into the actual current consumption and net RMS current. The discussion highlights the complexity of measuring 3-phase power, especially in scenarios where accessing each live wire is difficult. Understanding the power factor is also crucial for accurate power measurements. Overall, the conversation emphasizes the need for appropriate tools and methods for effective 3-phase current measurement.
karasumi
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Hi there all
I'm looking to measure current in 3 phase cables, and would like some advice on any current clamp models you'd like to recommend. However, I'm not entirely certain on the method as well; I've used current clamps before on single phase cables, and I'm aware that you need to clamp only around the live, as the fields of the currents flowing in the live & neutral cancel each other out. Is the same true for all instruments? For three phase do you have to clamp around each live individually, or is there a method just to clamp around the 5-core cable?
I only ask in hope as in the situations where I need to measure these currents it's tricky if not impossible to clamp individually to each live core
Thanks for reading
 
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I'd be interested in understanding 3 phase power better as well. I'm guessing that if you have 5 conductors you have 3 live wires each 2/3Pi out of phase with each-other, a return, and a ground If I had to go at it with my current knowledge, and the 1 multimeter I own, I'd measure the RMS current flowing in each of the lines which would tell me the actual current flowing. That's the current actually being consumed resistively plus the ebb and flow from capacitive and inductive components. I could also measure the current flowing on the return line which would tell me the net RMS current from all the lines. Then it would be a matter of figuring out power factor. Can anyone think of a better way; mine is pretty ghetto?
 
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