# Testing for electrical noise from an outlet



## brian john (Mar 11, 2007)

1st Are you having issues that you feel need investigating, if so what are the issues?

2nd. Most noise (typically 60 hz hum) is related to improper neutral grounding in which cases an amp clamp and multi meter are number one and two test instruments. High level of current harmonics will impose noise on a 60 hz waveform.

3rd a O-scope, Dranetz, RPM and several Fluke instruments will measure noise. Check the wave form at high resolution.


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## nathan.signature (Dec 11, 2008)

*what meter/tester would you recommend?*

i'm a low voltage installer. alarm, intercom, access control, cctv, structured wiring, home theater, and home automation systems. It would be nice to have a tester of some sort to determine how clean the power is coming into my systems. Sometimes I will have bare 110 electrical wire, but a lot of times I will be plugging into an outlet. Knowing how clean the power is could only improve the quality of my installations. What would you recommend?


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## nolabama (Oct 3, 2007)

had this pic handy - this is a scope meter - it aint cheap -


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## 480sparky (Sep 20, 2007)

nolabama said:


> had this pic handy - this is a scope meter - it aint cheap - (clip photo)


$2800, if you really want to know.

You're not going to find something like a 3-light tester you can plug in and get an indication that there's noise.


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## nolabama (Oct 3, 2007)

nathan.signature said:


> There's a tool out there that I can plug into an electrical outlet to test/demonstrate the amount of noise out it and subsequently in the tv and all of the audio/video equipment. Can anyone help me out with what different test devices are out there?


what would you do if you found some noise - how would you go about fixing it :no:


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## bobelectric (Feb 24, 2007)

They are advertising these Powerware things that clean up your power and make your electronics last longer.


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## brian john (Mar 11, 2007)

1st Noise is generally user generated, that is IN HOUSE, or all houses connected to the same transformer, A really good indicator of noise is the equipment you install. No equipment issues no noise. As I stated the main cause of interference noise in my expierence is; improperly grounded systems, there are downstream grounds on the neutral. Now in a house this would rarely affect the equipment as houses are generally wood frame so ground current traveling through equipment is minimized.

As for any particular item protecting electronic and extending their life. Go for a high quality TVSS at the service installed per the manufacture instructions, FEW to none are properly installed, to properly install a TVSS you must be able to read and that seems to be a course many electrician's skipped.

Next use high quality TVSS at the point of use. Most low End UPS's you would buy are single conversion that is they are online only during a power outage. If there are real issue, a double conversion UPS or isolation transformer works best.

But if you are like many on this forum go for the Scope meter, nice toy(and by that I mean man toy, like all tools you can never own enough.


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## ce2two (Oct 4, 2008)

:thumbup:I would use a power quality analyzer...not an o'scope ,:no:your just wasting your money on a scope for what you do ,:laughing:I own one like the one mentioned ,very user friendly ...$2800 to 3000 easy ...analyzer checks for noise , harmonics etc....


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## waco (Dec 10, 2007)

If there isn't a cheap, fast and dirty tester for power line noise, there sure should be and there sure could be. I agree with the other person who asked what you would do about noise if you found it and I would add, what standard would you use to decide if the noise was excessive?

Noise is usually harmonics of some base frequency, so a simple tester would simply allow you to "tune out" those harmonics using a simple LC or "Pi" filter.

If you have issues with noise in some real world application, I think there are power conditioners which filter and smooth source power. I know AC generator sources were once electrically incredibly noisy. I suspect they now have conditioners which clean them up a whole lot.


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## mike4355 (Jan 23, 2009)

*noise detection and display*

Try a Power Probe from Powervar Corp. powervar.com

It plugs into an outlet and displays noise on a O-scope. Use at least a 2-channel scope.

Need something cheaper? Get the cheapest AM portable radio you can find, with a dial tuner, not digital, tune off station, volume up all the way
and then walk the site. You will hear the noise, extend the antenna and you will be able to locate the source. Great for finding loose transformer connections.

Good Luck


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## macmikeman (Jan 23, 2007)

mike4355 said:


> Try a Power Probe from Powervar Corp. powervar.com
> 
> It plugs into an outlet and displays noise on a O-scope. Use at least a 2-channel scope.
> 
> ...


Man, I was pouring thru all the posts hoping that I would be the first one to mention using an am radio and you beat me to it.... good job.
I do that all the time, it also is great at finding computer printers that don't meet the FCC codes about antenna bleed.


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## All_amped_up (Nov 12, 2007)

macmikeman said:


> Man, I was pouring thru all the posts hoping that I would be the first one to mention using an am radio and you beat me to it.... good job.
> I do that all the time, it also is great at finding computer printers that don't meet the FCC codes about antenna bleed.



Wow, that a new one but makes perfect since. See...I've been doing this for yrs and still learning :thumbsup:
So I take it that with the untuned radio, the static you pickup as you get close to an outlet will tell you if it's "dirty" or putting out harmonics?


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## te12co2w (Jun 3, 2007)

Great thread, awesome info. The knowledge behind all these posts is priceless.


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## macmikeman (Jan 23, 2007)

All_amped_up said:


> Wow, that a new one but makes perfect since. See...I've been doing this for yrs and still learning :thumbsup:
> So I take it that with the untuned radio, the static you pickup as you get close to an outlet will tell you if it's "dirty" or putting out harmonics?


What I get with my current Radio Shack special is a high pitch hum sometimes, and a loud static hum other times. Both very annoying.


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## Mr. Sparkle (Jan 27, 2009)

Great trick of the trade guys, Thanks! :thumbsup:


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