Path: utzoo!attcan!uunet!husc6!bloom-beacon!bu-cs!purdue!decwrl!labrea!agate!helios.ee.lbl.gov!nosc!tetra!embick
From: embick@tetra.NOSC.MIL (Edward M. Embick)
Newsgroups: sci.electronics
Subject: Re: Polarized Plugs for 120 VAC
Summary: 240 VAC is 120 VAC 180 degrees out of phase
Keywords: house, wiring, safety, single phase, USA
Message-ID: <712@tetra.NOSC.MIL>
Date: 15 Nov 88 18:16:37 GMT
References: <686@bnlux0.bnl.gov> <4759@bsu-cs.UUCP>
Reply-To: embick@tetra.nosc.mil.UUCP (Edward M. Embick)
Followup-To: sci.electronics
Organization: Naval Ocean Systems Center, San Diego
Lines: 19

In article <4759@bsu-cs.UUCP> dhesi@bsu-cs.UUCP (Rahul Dhesi) writes:
>It seems to me that it would be far safer to have each of the two hot
>wires be at +/- 55 volts relative to ground.  A grounded center-tapped
>secondary would do it.
>
Rahul,
This is the way the 240 VAC is set up.  Each hot wire is 120 VAC relative
to ground.  The 120 VAC in you house is usually the neutral and one of
the two phases from a 240 VAC feed from the utility to your main power 
panel.  The 240 VAC then is used for electric range, dryer, hot water
heater, or other appliances without having to get additional service 
from the utility.  Your 120 VAC recepticles are usually divided between
the two phases to balance the loading on the 240 VAC source.
------------------------------------------------------------------------------
Ed Embick (If God wanted me to write legibly, He wouldn't have invented email)
Computer Sciences Corporation                               ____   ____   ____
4045 Hancock St.         MILNET:  embick@tetra.nosc.mil    //     //     //
San Diego, CA 92110                                        \\___  ___//  \\___
(619) 225-8401 x287