After removing our old built-in refrigerator from the wall, and before putting the new one in, I noticed that the plug that had been supporting the old fridge, has had a reverse polarity issue for these past 20 years. Opening up the box I noticed that the black wire was attached to the brass screw and the white wire was attached to the white screw, but the tester I was using pointed to a reverse polarity condition. Initially, I just reversed the wires at the plug and the tester said all was ok, but to further see what was going on, I pulled the black wire off the circuit breaker and did a continuitey check between that black wire and the white wire at the plug. The meter showed that it was the same circuit, so the question is, is it ok to paint the white wire black and the black wire white and then hook them up to eliminate the reverse polarity issue? Or is there something else that I need to do to verify the integrity of the circuit?

 

You must know what else is on the same Circuit as the fridge. Odds have it that somewhere along that circuit, there is a receptacle wired wrong, affecting everything "Downstream" from the mistake.

Reversed polarity, or "HOT GND REV" also indicates an open neutral, but since the receptacle works, this is unlikely.

You stated it has been like this for 20 years, And 20 years means you know what is on each breaker in your panel, and what each breaker controls. If you dont "Shame on you"....And NOW is the time to figure it out.

The location you are looking for could be a ceiling box , a wall receptacle, a splice box, a Light switch, .....Each just as likely as the next...But unless someone wired the breaker backwards, You will find something crossed somewhere.

Just as Im thinking......Did someone mix up the screws on the receptacle? The HOT wire should be the "SHORT" slot on the receptacle. A continuity check thru the affected receptacles will confirm this.

 

i believe your outlet was ok to begin with . The black/hot wire needs to be on the brass screw. The way I remember this is that brass needs to be HOTter to melt than alluminum. But when you face the outlet the hot should be on the right, neutral left. Also, the large slot is the neutral, small slot is hot.

Now, about that tester, it should be a three prong tester, i don't know why it would be telling you its reversed. Keep the black wire on your circuit breaker. either your tester is bad, or something ahead of the outlet (ie another outlet) is backwards.

Hope that helps
nova_gh
master electrician

 

Thanks guys,

I say 20 years because that's when we last redid our kitchen, and that's when that particular receptacle was installed, high on the wall for the Sub Zero. I believe that it's a direct run from the cb panel to the wall receptacle. As well, initially, the black wire was wired to the brass (hot/small) slot, while the white wire was wired to the long/common slot. The tester I'm using is in fact of the 3 pronged type. I'm thinking that perhaps, somewhere in the attic, where the wire was run, someone put in a junction box and married the white wire to the initial black one and the black wire to the initial white one, thus ending up at the receptacle with the white wire being hot and the black wire being the common. Again, without tracing back the circuit, am I ok with leaving the hot white wire attached to the brass screw/short slot on the receptacle and the black wire attached to the white screw/long slot? I was under the impression that reverse polarity was not that big of a deal, because except for a few delicate pieces of electrical equipment, all appliances, etc, are set up to handle this problem. Or am I way off base, as my wife always says I am?? Thanks again for your help.

 

The attic Junction sounds completely feasible....CHECK IT OUT!!!!

The fact that it has been that way for so long , and never caused a problem until you looked for one, means it is probably reasonably safe as it stands. However, "The Powers That Be" say that this is incorrect, and "UnAcceptable". You are stuck in the middle.

Yes the WHite and Black are crossed somewhere...You have the ability to reason this far, so the proper repair is not "BEYOND" your ability. I would suggest dedicating a Weekend to figuring it out, and correcting it, and "Be Done With It", Instead of losing sleep thinking about it for another 20 years.
A verified repair is also an excellent bargaining tool to plant your foot firmly on that base, and earn your wifes trust once and for all...

 

Your appliances won't know the difference, because you are dealing with alternating current.

However, from a safety standpoint, it is important that the hot and neutral is not reversed. From the hot to ground, you have a voltage potential of 120 volts or so. From neutral to ground in a properly wired circuit, it is nearly zero. The neutral is not as "neutral" as you might think, however, it does carry current, and you don't want to become part of that circuit!

Some appliances are built to treat the hot and neutral as if both were "hot". You can identify them with a plug that has the same size blades (and no ground).

Other appliances are polarized. For example, appliances that have switches are wired so that the hot wire is the one that's switched. Lamps are wired so that the neutral is connected to the socket and the hot wire is connected to the tab, thereby reducing the risk of shock if you should accidentally contact the socket.

I would check to make sure no other outlets in your kitchen or dining room are on the same circuit as your fridge. If they are, the problem might be in one of those boxes. And, as others have said, the connection could be anywhere.

 

NOT a pro, but this sounds pretty plausible to me, too. IF there is a juntion box, I'd bet someone wired in a switch pulling power form the box and when sending the white and black down to the switch did not color the white black and got confused in the junction box and connected the "real" white to the black.

Just my thought.
Tom

 

Left and right, or up and down have no relationship to which slot is the hot or neutral. You need to look at the terminal colors.