"Hot-neutral reversed" indicator on red receptacle tester

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Old 06-09-11, 04:23 PM
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Question "Hot-neutral reversed" indicator on red receptacle tester

Gents, this is my first post after I've looked through the forum for similar posts without success.

I am trying to replace an old, cracked three-prong receptacle in order to have a secure receptacle for a new computer. I have come across a couple of confusing things.

I'm sorry to say that I didn't label wires as I disconnected the old receptacle. The white wire was connected to the silver terminal, the ground wound around the grounding screw within the metal box and connected to the ground on the receptacle, and the black wire was loose but enclosed in a wire nut. That threw me.

I have installed the new receptacle with white to silver, black to brass, and bare copper to ground screw. First test with my red receptacle tester showed hot/neutral reversed. I reversed black and white and got the same test result, so one is obviously a false reading. From reading other posts, it seems as if there is no real ground, right? When I capped black as it was before, all three lights come on on the tester (and I don't know what that means).

Should I: 1) reconnect white to silver, black to brass, and copper to ground and pretend I didn't get the warning; 2) install a GFCI to avoid the lack of ground; or 3) use a different outlet to support the computer?

Suggestions and additional questions are welcome. If a photo of current connections would be helpful, I can do that. I appreciate you reading this and any information you can provide.

Thanks!

Dave
 
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Old 06-09-11, 05:43 PM
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Dave, welcome to the forums! You have a grounding wire. The bare wire (or green in some cases) is your ground. I don't understand why the black wire was not attached to the receptacle, and how you got a hot/neutral reversed reading if you had no power to begin with (black wire). Not sure what posts indicated there was no real ground, but we'll assume there is.
Now with all that said, your neutral may be reversed on another receptacle, and carried forward to your present receptacle. Are you getting the same reading at other receptacles in this room? If so, remove power to the receptacles and pull them out to check their wiring. Let us know what you find out. We're here.
 
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Old 06-09-11, 05:46 PM
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and the black wire was loose but enclosed in a wire nut. That threw me.
Throws me too. Are you saying the black was not connected to the receptacle, that it just was capped off with a wire nut? Was the receptacle working prior to this? Are there any other wires in the box you haven't mentioned.

With a multimeter make the following voltage tests and give us the results.

Black to white
Black to ground
White to ground
 
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Old 06-09-11, 06:03 PM
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He said his outlet was cracked. Seems like the hot was disconnected to make the outlet safe and unusable. Not sure why that person didn't just get a new receptacle.
 
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Old 06-10-11, 06:34 PM
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It does sound like a true "duh" moment to remove the cover, kill the power, remove the receptacle, remove the black wire, cap it off, and NOT put in a new receptacle. They were already coming down the 3rd base line toward home, with the ball still in the outfield, when they turned and went back to first. Cracker jack.
 
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Old 06-12-11, 09:19 PM
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Post A quick update and a couple of answers to questions

I got out my trusty multimeter and found just the red test lead, so I'll have to find a black one somewhere tomorrow (none of my neighbors have a multimeter). Sorry for the delay in test results.

In the meantime, I connected white to silver, black to brass, and ground the other night so as not to leave wires sticking out for my 3-1/2 year-old to pull or otherwise work on in the interim. I then used our vacuum cleaner (plugged into the receptacle in question) to clean up the little bits of insulation, etc., and dust. I turned it on and immediately noticed the red suction/filter light and a different sound than usual. The damn thing was running at least 50% faster than normal! I switched it off and unplugged it and was pleased I hadn't plugged in the new computer, even if it would have worked as fast as the machines of three years into the future.

I will check the upstream receptacles (this is the end of the run) and see if the hot/neutral reversal occurred earlier.

Yes, the outlet appeared to work normally for the past eight years or more, except being a little loose.

Yes, the black wire was disconnected from everything else and was capped with a red wire nut.

There is only one cable coming in and no unusual wires in the box.

Is it possible the the hot/neutral reversal occurred upstream (so my neutral was then hot) and adding the black current had some synergistic effect that almost killed the vacuum cleaner? Seems both intuitively plausible and wrong at the same time.

Again, thanks for your time and assistance.

Dave
 
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Old 06-12-11, 09:55 PM
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I'm guessing this started out life as a 240v receptacle. It was converted to 120v by disconnecting the black and using the ground for neutral. Plugging your vacuum into a 240 would sure speed up the motor.

Old timers story: Worked maintenance at an apartment building with window ACs and this seemed to be a practice of the previous maintenance man when going from a 240v unit to a 120v unit.

Is it possible the the hot/neutral reversal occurred upstream
If I'm correct both the black and white are hot.
 
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Old 06-12-11, 09:58 PM
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Lightbulb

Ray, I kind of thought it sounded like a 120 device running at 240. Your A/C theory is very possible, given the location of the receptacle (hallway, top of the stairs, in a dormer). Nice sleuthing. Don't know why it didn't occur to me when I flipped a double-breaker to shut off the circuit. Duh. What would I do to normalize things for the future?
 
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Old 06-12-11, 10:12 PM
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Simplest way is to remove the white wire from the breaker and connect it to the neutral bar in the breaker box.

Best would be to replace the 240v breaker with a 120v breaker. There is as far as I know though no code that says you can not use half of a 2 pole breaker for 120v. (Pros correct me if I am wrong.)
 
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