# Polarity in electronics & speakers?



## imola ghost (Aug 16, 2008)

Not sure if this is the right forum and don't flame for not knowing. I've been reading some things on checking the polarity of my home theater equipment and wall outlets.

How would I go about doing that with minimal cost? 

I mean is this really worth even doing? I do like tweaking almost everything I have and if this is something that could help then why not if the cost is minimal.

I'm not sure if I will even gain anything so if someone can tell me more about this subject I'd greatly appreciate it.


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## jeffreybehr (Mar 17, 2008)

Todd, get thee to a Radio Shack or Harbor Freight Tools or somewhere and buy a digital multimeter...or maybe you have one.

I can't be sure what others were writing about, but you certainly can determine if your AC outlets are wired correctly. As you look at the face of a US-standard, 15-Amp, 3-wire power output, notice that the 2 vertical slots are different height. IF--IF--IF your outlets are physically installed correctly, the earth-ground pin will be the bottom of the 3 'slots', the left-hand, taller slot is neutral/common/return, and the RH, shorter slot is hot. Set the meter on AC Voltage, and if it's not auto-ranging, set the range to the next-higher number than 120. 

Unplug everything from that outlet and slide the black lead tip into the ground slot and slide the red one into the RH slot. If the outlet's wired correctly, you'll get a Voltage reading of around 120. With the black lead still in the ground slot, slide the red lead into the LH, neutral slot. This should yield zero Volts, If your result is some number above zero, you should have an electrician check your home wiring, since the common/neutral/return conductor and the earth-ground wire are connected to the very same ground-buss wire in your breakerbox and should have zero-point-zero Volts between them.

If you get 120 Volts from ground to LH/tall slot and zero from ground to RH/hot slot, the outplet is wired backwards. Again, have an electrician check and correct these things.

The next task is measuring the Voltage on your equipment chassis and correcting plug orientations, but you have to be sure of your outlet wiring before you check the equipment.

Hope this helps, and let us know.


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## brucek (Apr 11, 2006)

I usually recommend that if someone has to ask how to check the correct wiring of electrical outlets, then for safety sake they should be buying one of these testers from Home Depot. 

Plug it into any outlet and the lights show if it is wired correctly or not.

brucek


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## imola ghost (Aug 16, 2008)

Bruce, I do have one of those testers.

Jeffrey, I completely understand you instructions. The last part of your instructions is what I plan on doing after I get past the electrical outlets. That was where my original post was intending to go.

Do you have information on measuring the voltage on my equipment chassis and correcting plug orientations?

Thanks guys for your information! I'm a newbie at testing with mulitmeter but I am confident before I check something that I read about what I'm trying to accomplish.


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## salvasol (Oct 31, 2006)

brucek said:


> I usually recommend that if someone has to ask how to check the correct wiring of electrical outlets, then for safety sake they should be buying one of these testers from Home Depot.
> 
> Plug it into any outlet and the lights show if it is wired correctly or not.
> 
> brucek


I think for a newbie (like me) this tester will be a lot easy and safer to use than a multimeter ... I'll regret if I something wrong and get a shot of electricity :scared: or worse, a big damage to wiring/panel..... :bigsmile:


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## imola ghost (Aug 16, 2008)

I think the Ground Fault Indicator is just part of the equipment that is needed. You'd still need a Multimeter to test the equipment. 

I'm sure my outlets are wired correctly since its quite new but I will test them anyway to take that out of the equation.

I'll wait for a follow up on how to test the equipment from a different perspective.


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