Failures in Outlet Testing Exposed

[Brian Hannigan]

I found this interesting

Why standard outlet testing methods fail to reveal reverse polarity bootleg ground miswiring situations

Failures in Outlet Testing Exposed | Contractor content from Electrical Construction & Maintenance (EC&M) Magazine (http://ecmweb.com/contractor/failures-outlet-testing-exposed)

[Raymond Wand]

Thanks Brian!

[Jack Feldmann]

Thanks for posting this!

[Don Hester]

Brian, good stuff. I used to play in bands for many years and was a victim of this exact incident.

[Ronald Kornmiller]

Excellent resource article. Thanks Brian.

[Lon Henderson]

Really good stuff.

I highly recommend going to the video link in the story.

[Mike Sokol]

Really good stuff.

I highly recommend going to the video link in the story.

Guys, I'm Mike Sokol, the author of the article you're discussing. Thanks for posting it here. Feel free to post or email me any questions on the subject of RPBG outlets.

Mike Sokol
mike@noshockzone.org
No Shock Zone (http://www.NoShockZone.org)

[Don Hester]

Mike, I was going to do you shock survey but it did not come up on the page. Anyway. When I was playing in bands in the 70' through 90's I would have been shocked on several occasions. It happened so frequently that I had a very good habit of testing my guitar against mic's and other stuff with the back of my hands.

Also could not count how many times we had to pull the ground pin also.

[Mike Sokol]

Also could not count how many times we had to pull the ground pin also.

Yup... Been there. Done That.

But I've been doing a lot of experiments lately about how to find and eliminate hums caused by ground loop currents. I now know how to ground everything properly, and reduce hum to virtually zero. These findings are a bit surprising to my pro-sound associates, especially as they relate to something I call GLID (Ground Loop Intermodulation Distortion). And it all goes back to how buildings and stages are wired and grounded. See Mike Sokol: Electrical Shock Prevention in Sound Systems - B&K Precision (http://www.bkprecision.com/education/projects/mike-sokol-electrical-shock-prevention-in-sound-systems.html) for my portable test bench where I demonstrate all sorts of grounding noise issues in sound systems.

But that's not a discussion for this forum. However, I may show you all the types of grounding issues that are discoverable during an inspection like you might perform. I think that could be very helpful to your business.

[Don Hester]

Mike, Are you trying to make me have Realtors hate me even more ;)

[Mike Sokol]

Mike, Are trying to make me have Realtors hate me even more ;)

Well, they need SOMEBODY to hate, I guess. Shame you have to be the bad guys, sometimes... :o

I work mostly in commercial spaces with large sound systems, and there's so many ways that safety grounds can be contaminated that it often drives the musicians and soundguys crazy trying to stop the hum. That's when they start doing dangerous things like cutting off ground pins. Unfortunately, in an effort to stop the hum, they can create a killer (literally) guitar amp or keyboard.

I've also written a number of articles about RV owners being electrocuted in their own back yards by an RPBG outlet in the garage or an extension cord with a broken ground pin, as well as pastors being electrocuted in baptism pools while holding hard-wired microphones. The pastor electrocution in Waco, TX was due to a mis-wired GFCI breakers and an electric hot water heater with a split in the hermetic seal of the heater element.

In most of these electrocution cases there were HUGE multi-million dollar lawsuits and settlements against the electrical contractors, with much of the details being sealed by the court due to the settlement agreement . So unless you were there, it's hard to find details without a court order.

I'll try to keep everyone posted of anything relevant about grounding and inspection.

Mike Sokol

[Don Hester]

Mike, I spent 20+ year in biotech/research and we had pretty strict requirements for power quality for very, very expensive research equipment and computing.

Back to your gig, I am sure glad that I never ended up electrocuted ;) I have received some pretty good jolts over the years.

[Jim Luttrall]

Thanks for the tip. I just found a hot/ground reversed in an entire master bath that would have gone unnoticed without using the non-contact tester in combination with the standard tester. This is a very hazardous condition just waiting for someone to touch the water pipe and the screws of the outlet at the same time. Much easier to test with this method than using a multi-meter and trying to find a true ground reference. Very good information. I'm going to share it with my musician brother-in-law!

[Mike Sokol]

Thanks for the tip. I just found a hot/ground reversed in an entire master bath that would have gone unnoticed without using the non-contact tester in combination with the standard tester. This is a very hazardous condition just waiting for someone to touch the water pipe and the screws of the outlet at the same time. Much easier to test with this method than using a multi-meter and trying to find a true ground reference. Very good information. I'm going to share it with my musician brother-in-law!

Since it only takes a few seconds to check an outlet for a hot-ground condition using a NCVT, I believe that all inspectors and electricians should add this quick proximity check to your other testing procedures (Ground Impedance Tester or even a 3-light tester).

I'm not suggesting a tic-tracer (NCVT) as a replacement for testing outlets with a good DMM or INSP-3/SureTest. But adding this additional proximity ground test to your standard outlet test procedure should allow you to find virtually 100% of all outlet mis-wiring conditions.

Your feedback is welcome. I'm an engineer and a bit crazy about measurements, but I want to know what you all think about this from an inspector's point of view.

Mike Sokol

[Jim Luttrall]

Since it only takes a few seconds to check an outlet for a hot-ground condition using a NCVT, I believe that all inspectors and electricians should add this quick proximity check to your other testing procedures (Ground Impedance Tester or even a 3-light tester).

I'm not suggesting a tic-tracer (NCVT) as a replacement for testing outlets with a good DMM or INSP-3/SureTest. But adding this additional proximity ground test to your standard outlet test procedure should allow you to find virtually 100% of all outlet mis-wiring conditions.

Your feedback is welcome. I'm an engineer and a bit crazy about measurements, but I want to know what you all think about this from an inspector's point of view.

Mike Sokol


Since I had already been using at NCVT checking for lack of bonding at appliances, fans, and pendant light fixtures, adding this to my routine added no significant time or effort to my inspection. While it makes perfect sense, I had never used the NCVT in this method until seeing this. Now having found a life threatening situation that I would have otherwise missed, this has become a permanent part of my routine.