Outlet Polarity

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  #1  
Old 12-13-11, 12:32 PM
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Outlet Polarity

Ever siince I've owned my home, if my wife runs her hair dryer in one room, the lights in another room pulsate ever so slightly. Is this a polarity issue? If so, how can I test every outlet for correct polarity? I have a simple outlet tester if that will help me.
 
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Old 12-13-11, 12:39 PM
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Dryer

Alternating current does not have "polarity". What you are experiencing is a momentary drop in branch circuit voltage when the dryer is turned on. The circuit may be borderline on being over loaded. Others will have additional thoughts.
 
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Old 12-13-11, 01:06 PM
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If the receptacles are 3-slot Ground-type receptacles you can test for "Polarity" with a receptacle test device that plugs into the receptacle.

"Reversed Polarity" as applied to a receptacle test means the Black and White wires are "reversed" , i.e. , on the wrong respective device terminals.

To test for a circuit problem when the dryer "loads" the circuit requires an accurate voltage reading at the receptacle terminals where the dryer connects.You need two voltage tests; one with the dryer off , and one with the dryer on .Any difference in the readings indicates a voltage "drop".
 
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Old 12-13-11, 01:29 PM
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Over the past 9 years as a home owner, I've noticed that many items are dedicated to one breaker. I may just have an overload problem. Someday when I have the money, I'll have an electrician add some more breakers in hopes of more evenly spreading the load.
 
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Old 12-13-11, 01:39 PM
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Look at the amperage of the hair dryer. You may find it borderline in using quite a bit. Bathroom receptacles are to be dedicated and GFCI protected, so you shouldn't have any other receptacles or lights on this type circuit.
 
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Old 12-13-11, 04:10 PM
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I think the outlet circuit for bathrooms is supposed to be 20 amps as well.
 
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Old 12-14-11, 05:36 AM
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What size circuit is serving your bath? What else is on the circuit?

It's not unusual for my wife to have hair curlers, a stick type curler and a blow dryer all going at the same time. That's a large load for a 15 amp circuit.

I'm sure there are older homes with a 15A single, non GFI outlet
in the bathroom.
 
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Old 12-14-11, 07:11 AM
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outlet polarity

The house was redone for 20 amps. The hair dryer I'm speaking of was being operated in our spare bedroom, and the spare bedroom lights are the ones that go dim. The two bathrooms have GFI outlets and take the load quite well. This happens when my parents visit and Mom uses her hair dryer in the spare room. It also happens when I run the sweeper in that same room.
 
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Old 12-14-11, 07:46 AM
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That makes sense. The outlet in the bedroom is probably a 15A general purpose circuit. A high wattage hair dryer combined with other loads is probably why the lights are dimming.

I don't think that the outlet wiring could be causing the problem, but a handy device to have is an inexpensive plug in outlet tester that you can by at any home center. It will confirm if an outlet is wired correctly.

I'm not an electrician but while it's true AC voltages have no polarity, outlet nomenclature (rightly or wrongly) considers polarity of the individual receptacles. I believe that an outlet with receptacles of differing sizes (as most are) are considered polarized. I think in this case hot-neutral are considered the different polarities.

To answer the OP's question - the small blade receptacle is hot, the larger one is neutral.
 
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Old 12-14-11, 08:48 AM
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Not mentioned yet are backstab connections on the receptacle. If the wires on the receptacle are inserted into holes in the back of the receptacles they need to be moved to the screws.

Note there is a third type of wire connection unlikely to be found in residential use except for GFCIs and that is called back wired. The wires are held by pressure plates tightened by screws. Those connections are fine and just need to be checked for tightness.

It would also be a good idea to check inside all wire nuts on the circuit for corrosion but it is likely just normal dimming from a heavy load starting up. "Polarity" does not cause it no exceptions.
 
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