[Shop-talk] 110vac outlet question

[Doug Braun]

Those testers in a plug with three little lights do a rather primitive test that can easily be wrong.  They only indicate the no-load voltage difference between the different lines.  They do NOT check against a true ground, and they do NOT tell the difference between a "real" voltage on a properly connected line vs. a leakage (e.g. capacitively-coupled) voltage on an open line.

Somebody could hook the hot line to the ground and neutral terminal, and the neutral line to the hot terminal, and the tester would not show a problem.

Doug


--- On Tue, 12/9/08, Frank Vantacich <rustymetal at sbcglobal.net> wrote:

> From: Frank Vantacich <rustymetal at sbcglobal.net>
> Subject: Re: [Shop-talk] 110vac outlet question
> To: "Randall" <tr3driver at ca.rr.com>, "'Shop Talk'" <shop-talk at autox.team.net>, "Karl Vacek" <KVacek at Ameritech.net>
> Date: Tuesday, December 9, 2008, 11:41 PM
> Thank you for the feed back. I have 87vac on the small slot
> and 27vac on the
> large slot. I bought a brand new circuit tester made by
> Sperry, it also
> verifies GFI receptacles, it shows the receptacles are OK.
>  
> My original posting was a result of my new barn not passing
> the final
> inspection due to an open ground.  I have since learned
> that two different
> testers were faulty, my new tester proved everything is OK
> and my barn was
> signed off. Yay!