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How To Do You Measure the Quality of Your AC Power?

What is the best way to measure the quality of the AC power feeding your listening room? Is there a device you can plug into an outlet that will give you the voltage, frequency, the total amount of distortion relative to a perfect sine wave, etc.? Furthermore, how would you measure the ability of your AC main to deliver transient currents?
It seems like there may be a scenario where you could measure your power quality to be excellent but somewhere in the line you could have a loose or poorly made wiring connection which under heavy load (such as powerful bass notes) you could run into trouble with power delivery. In this scenario, an AC regenerator would not help you, or would help very little.

Just curious what methods people have come up with to systematically analyze their power and how they use those measurements to drive buying decisions or repair work, if needed.

Edit: My apologies for the title typo.
128x128mkgus

Showing 3 responses by erik_squires

erik_squires
15,627 posts
 
I could never figure out why the load on the two legs has to be balanced, do your electric devices all turn on and off at the same time? There is always going to be an imbalance.


The requirement to be balanced is not to within 0.0001 %, but to avoid severe imbalances, especially at 50% or higher load. Being within 20% is probably OK. This reduces the need for the neutral to be 2x as big, and I believe also has consequences on the transformer.

If you have a 200A service and are drawing 30A you care a lot less.

erik_squires
15,627 posts
 
I use something very similar to this little gadget since it measures the main and neutral at the same time.

A good indicator of poor or loose wiring is either the main voltage dropping, or the neutral voltage rising.


https://amzn.to/3m0kEzW

Sadly the one I actually use is no longer carried, but you get the idea.
erik_squires
15,627 posts
 
Make sure your switches and outlets use real wire wrapped screw tightened connectors.

The little hole for the backstab connections are poor and I'm not even sure they are legal anymore. 


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