GFCI receptacle tester says hot/neutral swapped, what does that mean?

Question

This particular outlet has over the last few years sporadically caused electrical sparks when plugging equipment that was plugged into it in. On a whim I got a tester, and while the rest of the house is "Open Ground" (this is known, the house was build in '59), this one says hot/neutral swapped. I don't know much about electricity but that seems very bad.

Would that cause the sparks? What other problems are associated with the wiring being swapped like that?

Answer 1

I can't tell you what is causing the sparking, or more likely 'arcing', without seeing it. Is this happening in the appliance or at or in the plug socket when you plug it in?

Did you cut or break off a grounding pin? Are you using a grounding adapter (http://dualelectronics.com/shop/images/S...

There are two wires going to the plug socket, usually black and white. The black wire is (should be) the 'hot' and the white is (should be) the 'neutral'.

Most plug sockets are also 'color coded'. The neutral side should be a white or silver colored metal, and may even have a "N" near it. The hot side will copper (goldish color), and may have a "H" near it. The Hot side will also have a slightly smaller opening and the Neutral side will be a bit bigger or longer.

On very old houses, with sockets that have both sides the same and are not marked the hot side will be the one on the right and the neutral on the left - but then upside down they're reversed so it really doesn't make much difference. if you use a grounding adapter make sure which side is which.

On newer grounded plugs (since sometime in the 60s) the Hot side is smaller because it is the one that is the more dangerous, making it harder to 'get into'.

Before working on any of this, make sure the fuse controlling this circuit is removed or if your house uses circuit breakers that it is turned off. Plug a lamp in and turn it on. When you remove the fuse or turnoff the breaker the light should go off.

You should try the tester with one of those grounding adapters, with the wire attached to the cover plate s***w -- it should not show a open ground. You should also always use a adapter with any stuff that has a grounding plug, especially your PC.

You should also check all the sockets on this circuit, or maybe all in the house. It is also advisable to call a licensed electrician to take a look and do any repairs.

Good luck.

Answer 2

your polarity is reversed, switch the two wires  

Answer 3

your polarity is reversed, switch the two wires

Answer 4

GFCI means Ground Fault Interupt Circut. they are desighned to allow the circut to break. They should be run on thier own individual circut. The sparks you are seeing is from improper wiring. If you feel up to it Home Depot has books on wiring to further explain how GFCI's work and how to properly wire them. A licsened electrition while the cost is more is recommended.

Answer 5

Please don't listen to Rockstar and Stan.  I hope they just mistyped what they meant.  A little history behind all of this.  As everyone is well aware of, we as humans have become increasingly more and more technologically advanced and we've all learned from our mistakes.  k**b and tube wiring was outlawed, "rag wiring" proved to create too much heat and rotted out the cable too quickly, the importance of a grounding wire became evident, aluminum wiring turned out to not be a good idea and so we had to come up with ways to correct these issues.  Back in the 50's and 60's, it didn't matter which side the hot and neutral was, which is probably why you have reversed polarity or it could be that you have "rag wire" and the person who wired the receptacle couldn't tell which was the hot and which was the neutral anymore.  The National Fire Protection Association has been the "watchdog" for preventing fires and saving lives for well over a 100 years now and the NFPA 70 National Electric Code actually covers how to treat your particular type of wiring.  It says that if your house wiring doesn't have a ground wire in it (doesn't know "ground"), then the receptacle should be replaced with a non-grounding type receptacle or replaced with a GFCI receptacle.  The theory being that if the power going through the hot doesn't equal the power going out the neutral, then it will trip and save someone's life in the process.  

As for swaping the wires, yes that probably would solve your problems.  As for what is causing the sparks......it might have to do with what you're plugging into the receptacle.  If you plugged in a simple lamp, it probably wouldn't cause any sparks, but if you plugged in a computer or something else that absolutely has to have the "neutral on the left and hot on the right", it might cause sparks.  Then again, there could be problems other than polarity with that particular receptacle.  

As for the adapters that were afore-mentioned.......they're not necessarily safe....they are just designed to keep people from cutting off the grounding prong on extension cords and equipment designed to have a ground.  Just to set the record straight...........

Answer 6

Okay the first thing, don't plug back into that.  Is the outlet polerized like most newer outlets? (one slot bigger then the other)  Your black wire is the hot wire and your white is neutral.  Shut your breaker down and swap the two wires around.  Normally their are two different colored screws, a copper and a silver.  Copper s***w (black wire)  silver s***w (white wire).  Don't worry about the open grounds I just had to add more breakers and outlets to my own older home and the older outlets are the same way.

Now if it is already hooked up that way on that outlet.  Follow the wires because they are reversed elsewere, wether directly at the main panel or at the following outlet before it.

Answer 7

the polirity can be reversed the white wire is the grounded conductor and should be on the silver s***w the black wire is the current carring conductor and should be on the gold s***w the green or bare wire is the ground wire and should be on the green s***w.

Answer 8

as you know

house built back then are 2 wire systems

hot and neutral with no ground wire present

some use the old bx wiring and used metal boxes

in those case the ground came from the metal armor jacket being bonded to the box and then back to the service panel. from there they sometimes ran a bond to either a cold water source or a ground rod ( if at all )

the GFIs ( new ones ) generally do not worked if wires backward ( polarity switched ) as they are smart locked now a days.

on all receptacles and GFCIs the s***w terminals are color coded

the brass ones are always the hot side, the silver or chrome are the neutral, the green is always ground.

however in really old wiring sometimes it's hard to tell which one is hot and which one is neutral with the power off since i have seen old wiring in which both wires were the same color ( black or white )

some things will worked with the polarity switch

but some will burn out immediately

as for sparks

that usually cause by loose wiring

electricity will away seek a connection

and even if nothing is plugged in, the current is always present in the device ( switch, receptacle ), GFCI always draw a little power even if not in use

when the connection is loose, the current will attempt to make the jump and arc or spark as it tries to make the connection

it is why ARC fault breakers ( AFCIs ) are now required in bedroom circuits, since the NFPA found that most bedroom fires are caused by arcing lamp cords and such

GFCIs work in a similar fashion, though they detect current leakage  by comparing the incoming current to the outgoing current and do not allow for  a small deviation in difference ( hence the leakage ), if they sense the leakage they trip and open the circuit

if there is only 2 wires in the GFCI box, then do NOT place them on the LOAD side, it ( the GFCI ) will not work, they only time you place the wires on the LOAD side of the terminals is you have other receptacles that you are protecting upline of the GFCI .

Answer 9

Yeah, basically, that's a very bad mistake on the part of the electrician that wired your house.  Really bad.  Your hair dryer and some other devices have a self-grounding neutral, rather than an isolated ground.  This means that when the device is plugged in, the electricity is running through the frame and grounding before it runs through the motor.  This can cause a spark when the device is plugged in because the electricity has a place to jump to with little resistance.  Swapping the hot and neutral is an obvious fix to the problem.  I'm sure you've had the breaker blow a few times when using this GFI.  Turn off your breaker to that area and test the GFI to make sure it is no longer hot.  Remove the cover and pull out the GFI.  Find the black and white wires and swap them.  The black or hot wire should be inserted into the terminal labeled "line", while the white or neutral should be inserted into the "load" terminal.  Replace the GFI and cover and turn breaker back on.  If the breaker immediately trips, you've grounded the hot.  Re-test the GFI.