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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.
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clearthinker's avatar
clearthinker
1,582 posts
 
Dimming lights from an exercise machine???????????

That's serious.  No-one else gets that, although I used to get it when I powered up my old Krell.
Sounds like you've just got bad or old or damaged house wiring.
Get a competent electrician to re-wire the house.  Put the hi-fi on a dedicated circuit back to the company fuse with 20 amp wire.
Then enjoy the music!

hilde45's avatar
hilde45
5,167 posts
 
@jea48 Thanks for the very practical answer and to @tvad for the tip on contacting the electrical company. We'll see how they react, and if they can come out, I now have a practical list of what to ask them to check.

I've asked this question before on threads and this is the best answer I've read to date. No condescension, just expertise. Appreciated, Jim.

invalid
1,257 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.
tvad
11,620 posts
 
@hilde45:
@jea48 Thanks for the very practical answer and to @tvad for the tip on contacting the electrical company. We’ll see how they react, and if they can come out...

Tip: My electrician said to tell the Power Company that we had a problem with dimming lights, which would provide a reason for the Power Company to do a power quality check.

The Power Company found a neighborhood transformer that needed replacing, and they also found something on our power distribution pole that needed replacing (as well as a few neighbors, so they benefitted too).

They also tested every breaker in my panel for continuity (I think the term was continuity...it’s been a while), and said quite a few were out of specification and should be replaced, which I had my electrician do.

Thank you to @vk_onfilter for directly answering the OP’s question.
musicfan2349's avatar
musicfan2349
243 posts
 
Dimming lights? Treadmill affecting things? Let's start with something simple!
Most modern outlets use some sort of wire capturing spring. They're quick and easy to install. Strip and insert wire, done. While they may hold the wire fine, IMHO they're crap for a SOLID connection. If you're competent enough I'd suggest the following: Kill the power at your breaker box. Pull the outlets in your audio room and redo the connections using the *screws* on the sides of the outlets. (Or have an electrician do it, even better.) This will give you more conductive surface area and a more SOLID connection. I've done this in a couple homes I've owned and it made all the difference. No more dimming lights during loud, bass heavy music. Good luck!

Happy listening!
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