Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!mips!samsung!umich!sharkey!fmsrl7!art-sy!news From: chap@art-sy.detroit.mi.us (j chapman flack) Newsgroups: sci.electronics Subject: Re: polarity Keywords: polarity, stupid, babooze Message-ID: <9104271838.aa00690@art-sy.detroit.mi.us> Date: 27 Apr 91 22:38:24 GMT References: <11864@jarthur.Claremont.EDU> Sender: chap@art-sy.detroit.mi.us (j chapman flack) Reply-To: chap@art-sy.detroit.mi.us (j chapman flack) Distribution: usa Organization: Appropriate Roles for Technology Lines: 27 In article <11864@jarthur.Claremont.EDU> cliff@jarthur.Claremont.EDU (Clifford Stein) writes: >What's the purpose of polarized wall outlets with an AC >signal? I don't understand. Is it really bad to force >something to plug in the wrong way? >I am serious. With a real AC signal (sinusoidal waves) I can see no reason >at all for it. How can the electrical equipment tell? The equipment can't tell, but under certain abnormal conditions the *USER* can tell, and would much prefer having the equipment wired properly. One of those two conductors (the one connected to the WIDER slot in a U.S. 120VAC receptacle, provided the installer was competent) is very solidly bonded to ground potential. The other isn't. Equipment is designed so the grounded conductor ("neutral") is the one you're more likely to come into accidental contact with (e.g., the screw threads of a lamp socket), or the one that's more likely to come in contact with the equipment case in the event of some internal failure, etc. There may be additional reasons as well, but those are good enough for me. I was able once to tell my former employer that he had hot & neutral reversed, simply by leaning on the panel he'd built. (Ouch!) That episode earned me the title of "Official Ground-Fault Detector." -- Chap Flack Their tanks will rust. Our songs will last. chap@art-sy.detroit.mi.us -Mikos Theodorakis Nothing I say represents Appropriate Roles for Technology unless I say it does.