Whats a good economical way to test the electricity on a circuit?

Hasn't heard Michael Fremer say ONE dedicated line, and then explain how audiophiles used to believe you needed more, "which is a really stupid idea" (his words not mine!).  

Like I said, its not that you can't measure the noise, its that its a waste of time. Because the noise is there. Guaranteed. And so being as we all are limited in our time and money it does no good - no good at all - to spend time and money only to confirm what we already know: there is indeed noise!  

People can prove this in like ten minutes. Already explained exactly how to do it. How many have bothered to try? Zero. Yet here we are reading all their uninformed opinions. 

What someone should do, maybe I will, cut and paste all the same old posts so next time someone asks the same question we can provide all the wrong answers in one fell swoop. 

Please someone go flip the breakers. There's only like a dozen people I have done this demo for, most of them absolutely convinced it was BS, half of them not even audiophiles, every single one shocked at how obvious a difference it was. One guy his wife, I said What's your favorite song and played it for her, then excuse me a minute went and flipped the breakers came back do you mind if we play it again? Instant it was done she is all excited says What did you do it sounded SO MUCH BETTER!!! 

Yet here we are whole slew of audiophiles supposedly willing to do anything to get better sound yet too lazy to try this one simple trick. But all with time to post misleading opinions. Sad.
https://ultimist.com/video/2018/07/21/michael-fremers-listening-room/
Skip to 15:50. Please.

Here's what is going on, as best I can understand it. Which is way better than most. No one else here even comes close to having done as much or as many different things to improve power to their system. Challenge! This is only the tip of the iceberg https://systems.audiogon.com/systems/8367 

Every wire is an antenna. Electromagnetic radiation of every kind crosses every wire inducing a signal in that wire. That's the improvement you hear flipping off the breakers, it reduces RFI by cutting off a whole slew of antennas. This is separate from back EMF noise in the line from devices that are connected and running. 

Those two things together are only part of the problem. Another probably even bigger one is transmission efficiency. Our systems do not draw power in a smooth even flow. Its extremely uneven and varies constantly with the music. Just how much this matters is very easily demonstrated by something as simple as swapping out diodes or caps in the power supply. 

Every little connection along the way is a gap the power has to bridge on its way to your system. You think its a solid connection. You think there's no gap. On a microscopic level its craggy as the moon. You think the power flows. On a microscopic level electrons are piling up until there's enough and then zap they jump across the gap. Marketing people call this micro-arcing. Audiophiles just love marketing lingo. You are well on your way to wasting a phenomenal amount of time chasing marketing lingo, measuring and all of that. Monumentally huge waste of time.  

This is why I say to relax. You're all worked up thinking there's something there you can search around and find the answer to. Well there is, and there isn't. There isn't in the sense you cannot find any one thing to point at and say do that and done. There is in the sense you can say its all crap and so anything and everything I can do to make it better is a step in the right direction. Just know its like taking a step here on Earth. You can walk your whole life and never run out of steps. Round and round. Enjoy your walk. Its endless.  

Almost forgot! There is one free and very simple test you can perform to hear for yourself just how much noise there is in your AC. Get your system nicely warmed up. Listen to your favorite music. Go to your panel, flip off as many circuit breakers as you can. Ideally everything but what's needed for the system, but for sure do water heater, stove, refrigerator, spare rooms, stuff like that. Go back and play that same music again. The huge improvement you just heard- blacker background, clearer details, improved dynamics, with less grain and glare - is all due to the reduction in noise from separating the system from all those other circuits. You will hear it. And once you do, you will understand why you do not need no meter. Because you have something better: ears. 

Go and listen. You will see.

Relax. The one thing we know for sure is its noisy, dirty, whatever you want to call it. The other thing we know for sure is if you do find something to measure and quantify this it will do absolutely nothing for you. Because we already know its noisy, and we already know what to do about it. Actually its even worse than that. Because if you measure something then that's what you think needs to be fixed, and all it does is set you up for someone's marketing story they want to use to get your money. 

So what you do instead is talk to people, read reviews, listen to different things, and buy whatever improves the sound. Power cord, fuse, conditioner, TA-102 tape, TC, outlet covers, whatever. All these things actually work and can hugely improve performance. I have no idea whatsoever how they made the AC sine wave look different on a scope. Nor do I care. Nor should you.