Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!att!cbnewsc!psfales From: psfales@cbnewsc.ATT.COM (Peter Fales) Newsgroups: sci.electronics Subject: Re: How can I recognize true ground? Message-ID: <1623@cbnewsc.ATT.COM> Date: 7 Jul 89 22:47:20 GMT References: <18425@mimsy.UUCP> <1989Jul7.155721.19105@utzoo.uucp> Organization: AT&T Bell Laboratories Lines: 43 In article <1989Jul7.155721.19105@utzoo.uucp>, henry@utzoo.uucp (Henry Spencer) writes: > In article <18425@mimsy.UUCP> spector@brillig.umd.edu.UUCP () writes: > >Question from a novice: My house has "two prong" outlets. I've been told > >that the center screw and casing of the outlet boxes is generally grounded, > >so that I will have a correctly grounded outlet if I attach the wire of a > >"3 to 2 adapter" to the center screw. How do I (a vertual electronics > >know-nothing) check to see if this is working in my case? > > If you are really, seriously concerned about whether it really is grounded, > you can't assume that the screw is grounded, and in fact you can't assume > that the third prong in a three-prong outlet is grounded -- electricians > do get sloppy now and then. > > I'm unable to think of a quick no-equipment test to make sure; perhaps one > of the higher gurus can. If I understand what you are asking, any hardware store should have an AC line tester. This is not a "no equipment" test, but it doesn't cost more than a couple of dollars, and is a small device about the size of a three prong plug containing two green and one red neon bulbs. When you plug it into a three prong outlet (or your grounded 3-2 adapter), it will show several common wiring errors such as reversed hot/neutral, missing ground, and a few others. It is probably not 100%, but it gives you a better feeling. I found several outlets in my house with hot/neutral reversed. i n e w s f i l l e r -- Peter Fales AT&T, Room 5B-420 2000 N. Naperville Rd. UUCP: ...att!ihlpb!psfales Naperville, IL 60566 Domain: psfales@ihlpb.att.com work: (312) 979-8031