Path: utzoo!attcan!uunet!tut.cis.ohio-state.edu!brutus.cs.uiuc.edu!apple!xanadu!michael From: michael@xanadu.COM (Michael McClary) Newsgroups: sci.electronics Subject: Re: grounding by pipe (was ... true ground?) Keywords: ground, pipe, electrocution Message-ID:Date: 12 Aug 89 12:40:23 GMT References: <741@encad.wichita.ncr.com> <4474@merlin.usc.edu> Reply-To: michael@xanadu.UUCP (Michael McClary) Organization: Xanadu Operating Company, Palo Alto, CA Lines: 36 In article <4474@merlin.usc.edu> guncer@nunki.usc.edu (Selim Guncer) writes: >how about using the "ground" as ground (:-)). back home (in Turkey), >as new ee majors, we were operating our electric heaters by connecting >one end to the live terminal, and the other end buried in the front >garden. since the return path was not provided, we weren't charged for >the electricity! ofcourse, whoever did happen to jump over the fence >and step in the garden may have been electrocuted. If they provided service and meters of the same sort as you find in the U.S., you paid for the energy you used in the heater, plus the energy lost heating the ground. The typical watthour meter has two current windings (one for each of the hot sides of a 220 center-tapped feed), and one voltage winding (connected between the two hot lines). When you draw power between the two hot lines, the current is counted twice (once for each winding). When you draw power from one side and return it through neutral, it only gets counted once. If the neutral's voltage is exactly halfway between the two hot feeds, you got exactly half the power, so it comes out right. If the neutral is a little off, say because of voltage drop from a crummy connection, you get to pay for the power lost in the voltage drop as well. (If it's off to one side because you're placing a light load on one side and your neighbor is placing a heavy load on the other, he gets to pay a smidgeon of your bill.) In a 110 feed (rather than a center-tapped 220 feed), you may find the meter wired so both the neutral and the hot side go through current windings. In this case, you save half your bill by bypassing the neutral current winding. (If it's wired with just one current winding, though, you're back to the same case as the 220 feed.) - - - - - - - - -