Reversed polarity electrical receptacles:
Definition of reversed polarity at an electrical receptacle, its causes, cures, and dangers. What happens if you reverse the hot and neutral wires at an electrical receptacle? We also explain the difference between reversed polarity and reversed LINE - LOAD connections in a building electrical circuit.
This article series describes how to choose, locate, and wire an electrical receptacle in a home. Electrical receptacles (also called electrical outlets or "plugs" or "sockets") are simple devices that are easy to install, but there are details to get right if you want to be safe.
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On 2017-03-16 17:24:37.178601 by (mod) - do I need to correct reversed-polarity outlets in an older "grandma" or "grandfathered" homeCorrecting reversed polarity outlets means correcting an UNSAFE condition as described in the article above, Philip, but it won't change the level of usage of electrical energy.
On 2017-03-16 01:56:59.156654 by Philip
I live in a very old colonial home. Approximately 100 years old. The inspector says everything electrical checks out okay. However the grandma law says that the home can function safely.
Some of the receptacles are reverse polarity. Which are currently working fine. There are only 5 of them reversed in a three story home. Question! Will I save on energy if I correct these outlets?
On 2016-05-29 20:37:57.222628 by (mod) - live wire stops working if I connect two neutral wires
WATCH OUT: mis-wiring or electrical wiring damage or hookup mistakes can cause fire, shock, or death. That warning made, you may be joining two neutrals one or both of which is carrying current - something that should occur ONLY if an appliance or device on the circuit (lighting, an appliance, etc) is operating;
I suspect that the two neturals may be carrying current from two different buses in your electrical panel, and /or that there is a wiring error somewhere connecting neutral to "hot" in the system.
I would turn off all of your circuits, then turn on and test them individually.
On 2016-05-29 14:37:38.356600 by Mr B LockwoodMy live wire stops working when I join the neutral wires together. What's wrong please.
On 2016-04-12 13:37:57.997574 by (mod) - should you reverse-wire a GFCI outlet if home was built before 2003? NO!NO Sam. That is not correct.
On 2016-04-10 00:34:05.596893 by SamAre you supposed to wire a gfi outlet reverse if the construction was done before 2003?
On 2016-03-27 15:40:00.505072 by (mod) - why would someone deliberately reverse wiresSounds like wiring errors to me. I've seen deliberate cross-wiring of receptacles in a desperate situation where someone could not find where, upstream from the receptacle, somebody has made a wiring error - say at another device (receptacle perhaps or a splice in a junction box).
On 2016-03-27 09:10:50.555825 by AnonymousWhy would someone wire an end run outlet and reverse wiring as white to brass and hot wire to silver? Upon replacing outlet and wiring it correctly; it does not work but the rest of the circuit works
On 2015-11-21 16:51:17.517903 by (mod) - why would a receptacle "push the plug back out"Thanks CB. do keep us posted: what you learn will help other readers.
On 2015-11-20 20:19:15.141350 by CowboyThat is the first thing I thought of but took her to the company bathroom and showed her the GFC. She said that is not what she has, she has just the two slots, no ground. I asked her for a video showing what she is telling me. I will let you know.
On 2015-11-19 18:22:38.117915 by (mod)Cow
On 2015-11-18 15:58:13.216351 by CowboyOne of my office girls says she has several outlets in her 1970's house that, when one appliance is already plugged into a duplex and she tries to plug in another (phone charger, vacuum, etc.) it "pushes" that plug out. I have never heard of this. Any ideas?
On 2015-01-08 02:42:54.755620 by (mod) - reverse polarity is a red flag to look for other electrical wiring mistakesMet
On 2015-01-07 22:17:45.706740 by email@example.comAfter testing all the outlets in a new shop building on the property we just bought, all outlets were RP and I turned all power and corrected the problem. Now I have lights dimming and appliances that are hard wired not working properly; can you assist?
On 2014-12-02 22:29:03.065320 by (mod)Jones
On 2014-12-02 04:58:34.216400 by JONESWe are using a simple line tester in normal case the construction will be like that( Live contact rod+resistor+ neon lamp+ spring+metal cap)
You want to start at the beginning of each circuit and check for not just reversed polarity but shorted wires including both short to neutral and short to ground, and also neutral shorted to ground.
I've found, especially in older apartments such as in NYC, that someone who over-tightens the connectors on armored cable wiring (BX wire) can cause the metal wire jacket to cut into the hot or neutral wire.
In general I'm never comfortable correcting the wire at just a single outlet in a mis-wired outlet chain. Given that incompetent wiring was performed, you don't know where down the line someone "fixed" an operating problem by connecting a white to a black wire in a junction box.
So what makes sense is to start at the first receptacle in the electrical panel and follow all of the connections and splices throughout the circuit.
Where a receptacle is not working you want to open the electrical box and check each of the incoming and outgoing wires for power and check that it's the black wire that's the "hot" wire not the white one (due to a reversed connection in the circuit)
Carson Dunlop Associates' sketch shown above points out that the white wire, i.e. the neutral wire, will be connected through the receptacle's internal parts to the wide slot on the receptacle face in order to assure that the neutral wire side of an appliance being plugged-in there is properly connected.
On 2014-09-05 20:17:26.149160 by Brian C.Apartment in a 90 year-old New York city building. Upgraded mid-century to BMX conduits. 20 years ago replaced fuses with breaker boxes in each apartment (2 or 3 breakers per 750 saq. ft. apartment.) Next to electrical meters in the basement there's a breaker for each apartment.
I have a 3 wire (Black, White, Red and ground) feeding a outlet and I want to add another receptacle to run further down the line. The line out is 14/2. What do I do with the Hot Red wire? Can i attach it to the ground. - Rick
NEVER connect a hot (red or black) wire to ground (nor to the white neutral wire) - doing so would form a dead short, should trip a breaker, or if not, could cause a fire or could cause a dangerous shock.
If there is a hot wire that is not used in a junction box, SOP would be to cap it off with a twist-on connector.
It sounds as if you'd be best served by hiring a licensed electrician.
After capping off the red wire, can I extend the line to the next plug by following the diagram above and adding the black and white wires to the respective second screw connections?
You see, the wiring has already been installed by the builders and they left the boxes without receptacles so all I have to do is connect them to the. I don't know why the extra red wire is there. It was done over a year ago. I want to finish the connections. It runs 14/3 and then 14/2. That's why I have the extra red.
I have changed several receptacles in my 1994 home, but this time when removing the receptacle from the wall I see a third white wire attached to the side of the old receptacle. Can you explain to me what this third neutral wire is? - DW 6/12/12
DW, it is just too dangerous to claim to know what wiring connections someone has made in a building that is unseen and untested.
It would be common for an additional white wire connected to an electrical receptacle to be carrying the neutral line to another receptacle downstream. In other words the incoming neutral is connected to one terminal and the outgoing neutral is connected to a second screw that is electrically common with the first.
Check for a second hot wire also present in the same box.
I've lost elec to the whole room.
I tested the wiring at the light switch.
If I turn the switch off I get elec to the switch,If I turn it on I get no elec.to the switch. I've lost electricity to the whole room - Dave
Dave, your wiring or perhaps the switch itself is unsafe; sounds as if it's shorted. Leave the circuit off until the wiring has been traced, lest you start a fire or zap someone.
Are receptacles wired after GFI receptacles OK? - Denny 11/25/12
Yes, and if wired correctly the downstream receptacles will also be GFCI protected.
Watch out: When wiring a GFCI the incoming leads are connected to the LINE terminals and the downstream receptacles are connected to the LOAD terminals marked on the back of the receptacle. If the devices is not wired correctly it is unsafe and does not provide the intended safety protection from ground faults.
Ok from everything I can tell I'm having trouble with trouble with 3 plugs on my outer wall has went out. I've did the common thing checked my breakers they are fine. Must not I have 2 switches in this room one on each wall but they do nothing I feel somehow those switches are connected to those 3 plugs. I've pulled the covers off each plug and noticed the wires are secured. I've flipped the switches in many combos with something plugged in and they still don't work at all. What can I do to fix it. I wanna avoid calling a electrician if possible. - Josh DeBerry 12/11/12
Start by checking fuses or circuit breakers. If there is no tripped breaker or blown fuse, I suspect a damaged receptacle, wire, or wire connector. Your electrician will track down the location of the fault. But if you know which receptacles were all wired on a given circuit, and with power on at the electrical panel, using a receptacle tester you can check to see if any of the devices on the circuit have power.
Since receptacles are most often wired in a daisy-chain or series circuit, the last one that has power tells you that the problem is between that receptacle and the next one in the chain.
Watch out: Electrical components in a building can easily cause an electrical shock, burn, or even death.
Even when a hot line switch is off, one terminal on the switch is still connected to the power source.
Before doing any work on the switch, the power source must be turned off by setting a circuit breaker to OFF or removing a fuse.
See SAFETY for ELECTRICAL INSPECTORS
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