Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!dsinc!wells!k3tx From: k3tx@wells.UUCP (Dave Heller) Newsgroups: sci.electronics Subject: Re: ANOTHER house wiring question (this one's basic) Message-ID: <882@wells.UUCP> Date: 13 Jan 91 00:57:47 GMT References: Organization: Wells Computer Systems Corp., Levittown, Pa. 19058 Lines: 58 In article , mrapple@quack.sac.ca.us (Nick Sayer) writes: > The radio shmuck testers seem to say, and a volt meter seems > to prove, that there is an AC potential between hot and ground > and hot and neutral, but there is no potential between neutral > and ground. > > Now ground and neutral clearly are not the same thing. I would > expect negative side effects were I foolish enough to hook > a light bulb between hot and ground. > > But wait! In AC, every half cycle the current goes the other > way! So why isn't there a potential between neutral and ground? > Inquiring minds want to know! > > What, exactly is the theory here? Ground is connected (basically) > to a big pipe in the dirt, and hot and neutral go up to the pole, > but some more details for a complete software weenie would be > great. > > -- > Nick Sayer | Think of me as a recombinant | RIP: Mel Blanc > mrapple@quack.sac.ca.us | Simpson: Homer's looks, Lisa's | 1908-1989 > N6QQQ [44.2.1.17] | brains, Bart's manners, and | May he never > 209-952-5347 (Telebit) | Maggie's appetite for TV. --Me | be silenced. There should be a continuous hot and return path for the actual power consumed. There should also for safety and many other considerations be a solid GROUND throughout the system. It is a fact that the so-called NEUTRAL is at ground potential, so technically shorting Neutral to Ground should be a zero-current affair. As a practical matter, NO. The Neutral is at "steady state ground" but may not be at the transient ground, especially under fault conditions. Neutral WILL be grounded, but at one place only, generally a ground rod below the service entrance. And this should be the only place. Continuity of ground is most important, however. Much new construction uses non-metallic (i.e., plastic) junction boxes, for which grounding is rather difficult. In my opinion the use of plastic boxes is a damn foolish way of economizing just a little bit. However, most contractors use the cheapest devices and junk they can get, on the premise that not every house miswired is going to catch fire (just a few) and that not every ;house fire does a lot of damage or kills somebody -- just a few, so the hell with it because they got paid for the job long since. Suggestion: what some "professional" electricians do is bad enough, but the doityourself stuff is often worse. If you have to ask, don't try doing it without EXPERT supervision. K3TX