Measuring wattage for individual PSU cables with current clamp?

[y3llowduk]

Hi All, I've seen gamers nexus a while ago use a current clamp thing to measure how much power is going through individual cable sets from a PSU. e.g. how much power the 8-pin cpu power connector is pulling. I know very little about this stuff... but I assume they measure current draw? So to get the power draw in watts you use P=IV with the voltage being 12V... DC right? Can anyone recommend a current clamp for this purpose? Just for fun and tinkering with overclocks.

 

Tia.

[Grabhanem]

Yep, you're correct in how that works. The one trick is that you have to make sure you only get the +12V and not the ground rails, because if you clamp the entire cable it'll average the current in both directions and read zero.

[y3llowduk]

7 minutes ago, Grabhanem said:

Yep, you're correct in how that works. The one trick is that you have to make sure you only get the +12V and not the ground rails, because if you clamp the entire cable it'll average the current in both directions and read zero.

Thanks for the advice! The only thing I noticed is the few I have seen online only measure AC current not DC?

[pd.]

38 minutes ago, y3llowduk said:

Can anyone recommend a current clamp for this purpose?

Estimate your power draw and choose any Fluke AC/DC Current Clamp with suitable range. Make sure it say DC. I would also go for true-RMS one if your PSU is not cream of the crop. Fluke is my brand of choise. It has a long history and is more expencive, howerver nowdays it is made in China same as many other brands.

[Guest]

33 minutes ago, y3llowduk said:

Thanks for the advice! The only thing I noticed is the few I have seen online only measure AC current not DC?

The cheap ones only measure AC.  The better ones can measure AC or DC.