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[John Penkala]

I just came across a venue where every receptacle had the Hot and Neutral reversed according to my Extech circuit tester. And yes, I've verified that the tester is working correctly. I'm thinking the reversal is at the panel. I would think this could be extremely dangerous under certain circumstances. I'd like to hear the opinions of the pro's here.

-JP

[John Roberts {JR}]

It is not automatically dangerous by itself. Line and neutral are both insulated inside properly designed  equipment.

However it is WRONG and should be corrected. 

It can be dangerous in connection with other wiring faults. 

JR

[Mike Sokol]

It is not automatically dangerous by itself. Line and neutral are both insulated inside properly designed  equipment.

Yes, in combination with a bootleg ground it becomes an RPBG which is REALLY dangerous. And if you're working inside of a piece of gear that's not unplugged from the outlet, everything that's connected to the incoming neutral will still be energized even if the switch is off. Never assume anything is off!!!

However, I just don't see how the hot and neutral could be reversed at the panel. And if this is a new building, how did it pass inspection?

[g'bye, Dick Rees]

Yes, in combination with a bootleg ground it becomes an RPBG which is REALLY dangerous. And if you're working inside of a piece of gear that's not unplugged from the outlet, everything that's connected to the incoming neutral will still be energized even if the switch is off. Never assume anything is off!!!

However, I just don't see how the hot and neutral could be reversed at the panel. And if this is a new building,how did it pass inspection?

This guy?

[Stephen Swaffer]

I just came across a venue where every receptacle had the Hot and Neutral reversed according to my Extech circuit tester. And yes, I've verified that the tester is working correctly. I'm thinking the reversal is at the panel. I would think this could be extremely dangerous under certain circumstances. I'd like to hear the opinions of the pro's here.

-JP

There really is no way to reverse this at a service panel.  The NEC refers to the neutral as the grounded conductor (different from the grounding conductor).  The neutral is bonded to the grounding conductor, making it the "neutral"-until that happens it is not really a neutral.  If any of the 3 wires (on a typical split phase system) feeding a subpanel are mixed up, you might run into a hot/neutral reversed scenario on half of the receptacles-the other half would have 240 volts across them because they would have 2 hots connected.

Of course, I am assuming the service panel is properly bonded-lacking proper inspections that might be a dangerous assumption.  Lacking proper bonding, the same could happen on the service panel as in the subpanel.

I would suggest shutting off the main breaker and having a qualified electrician inspect the system (or a qualified inpsector).  That pretty much rules out the installer-as a qualified installer should have verified his own work.

[Mike Sokol]

One of my RV readers told me about a new campground that had every one of the campsite pedestal receptacles wired with swapped hot and neutrals. This was a COE campground (US Army Corp of Engineers), so the wiring SOP document must have been incorrect, and the technician wiring the pedestals dutifully mis-wired some 50+ pedestals incorrectly.

Perhaps in your case someone drew a hookup diagram on a napkin from the front of the outlet perspective, and some non-electrician helper wired up all the outlets while looking at the back of the receptacles. That would do it.

[Mike Sokol]

Also, some of my church DIY helpers have wired receptacles with swapped hot and neutral wiring because they assumed that the longer slot on the receptacle must be hot. Of course the shorter slot is hot and the longer slot is neutral. As Sister Mary Charles back in 5th grade at Saint Mary's School would tell us, ASSume makes an ASS out of YOU and ME. That always cracked up all the boys in the classroom. 

[John Penkala]

There really is no way to reverse this at a service panel.  The NEC refers to the neutral as the grounded conductor (different from the grounding conductor).  The neutral is bonded to the grounding conductor, making it the "neutral"-until that happens it is not really a neutral.  If any of the 3 wires (on a typical split phase system) feeding a subpanel are mixed up, you might run into a hot/neutral reversed scenario on half of the receptacles-the other half would have 240 volts across them because they would have 2 hots connected.

Of course, I am assuming the service panel is properly bonded-lacking proper inspections that might be a dangerous assumption.  Lacking proper bonding, the same could happen on the service panel as in the subpanel.

I would suggest shutting off the main breaker and having a qualified electrician inspect the system (or a qualified inpsector).  That pretty much rules out the installer-as a qualified installer should have verified his own work.

I thought it might be reversed at the panel because literally every receptacle that I measured was reversed. Now I know better.  I had to have checked at least 15 on the second floor where I was. I even went downstairs to see if it was the same there. It was.  And, I was just in the conference center that is attached to an even bigger hotel with a restaurant. I did bring this to the owner's attention and they are taking it very seriously.

[Mike Sokol]

I thought it might be reversed at the panel because literally every receptacle that I measured was reversed. Now I know better.  I had to have checked at least 15 on the second floor where I was. I even went downstairs to see if it was the same there. It was.  And, I was just in the conference center that is attached to an even bigger hotel with a restaurant. I did bring this to the owner's attention and they are taking it very seriously.

Just how did you confirm that your Extech tester was measuring correctly? Are you using the original short Euro cable that came with it? You need to try an alternate testing method just to confirm your readings, as in "who will guard the guards"? If you buy a $5 outlet tester with 3 lights, what does it indicate? Before I send up a balloon I would triple check my readings.

Also, a visual inspection would tell you a lot. If you're authorized and trained sufficiently to be safe, just pulling a receptacle out of the box and looking at the wiring colors would point the blame in the right direction. 

[John Penkala]

Just how did you confirm that your Extech tester was measuring correctly? Are you using the original short Euro cable that came with it. You need to try an alternate testing method just to confirm your reading, as in "who will guard the guards"? If you buy a $5 outlet tester with 3 lights, what does it indicate? Before I send up balloon I would triple check my readings.

Also, a visual inspection would tell you a lot. If you're authorized and trained sufficiently to be safe, just pulling a receptacle out of the box and looking at the wiring colors would point the blame in the right direction.

I was in disbelief. Therefore , I did verify the Extech CT80 tester at home after the show and 30 seconds ago on my current show. It works as it should. Also, on the show that day I use 12ga SJ cables with an outlet tester that's integrated into the Edison connector. They usually glow green when all is good and red when something is wrong. On this day the green and red LED's were on simultaneously on all 4 of them regardless of where I plugged them in. I have never seen that.   

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