Post by thread:[PIC]: Newbie Q. re: electrical outlet and SSR

Hi all. Would someone please explain how to correctly connect a PIC-driven solid state relay to control a three pronged AC device? Does it matter whether the white or black conductor is interuppted by the SSR? (I assume that the green one is an earth ground.) Is this correct?: [From power cord] AC grn---------------------------------------------` | | AC blk -------------------------------- === | [Switched | AC Socket] O---' AC wht -----[~ SSR ~]----------------- ==== Andrew akieranATureach.com ________________________________________________ Get your own "800" number Voicemail, fax, email, and a lot more http://www.ureach.com/reg/tag -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

At 03:14 PM 2/6/02 -0500, Andrew Kieran wrote: {Quote hidden}>Hi all. Would someone please explain how to correctly connect >a PIC-driven solid state relay to control a three pronged AC >device? Does it matter whether the white or black conductor is >interuppted by the SSR? (I assume that the green one is an >earth ground.) > >Is this correct?: > > >[From power cord] > >AC grn---------------------------------------------` > | > | >AC blk -------------------------------- === | [Switched > | AC Socket] > O---' > >AC wht -----[~ SSR ~]----------------- ==== Black is the "hot" lead, and is the one that you should interrupt. In a series circuit, from an academic point of view, it does not matter, but from a safety point of view, I should never be able to touch a white wire that is hot. (loads of things violate this, but that's how it should be) -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

on 7/2/02 7:32 AM, David VanHorn at spam_OUTdvanhornTakeThisOuTCEDAR.NET wrote: Hey Dave, > Black is the "hot" lead, and is the one that you should interrupt. > In a series circuit, from an academic point of view, it does not matter, > but from a safety point of view, I should never be able to touch a white > wire that is hot. (loads of things violate this, but that's how it should be) As an Australian and too young to remember anything OTHER than a 3-wire MEN system, I am curious about the US 3-wire system. Is the White leg (equivalent to what we term a neutral, I assume) connected to Earth at some point in the building's electrical system or is it floating? ie; in a new building with 3-wire outlets throughout, is the white neutral leg tied to earth back at the distribution board? Also is the colour coding still Black, White and Green? The Green/Yellow combination is not used? I lived in Taiwan for about 8 years, and they STILL use what I assume to be a copy of the OLD 2-wire US System - One white and one black. I can tell you I never trusted either of those suckers and made sure there was a dual pole isolation switch between me and the nearest power station at all times - then checked with a meter just to be sure! :-) Regards, Sean -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

----- Original Message ----- From: "Sean Alcorn - Avion Sydney" <.....sdalcornKILLspam@spam@AVION.COM.AU> To: <PICLISTKILLspamMITVMA.MIT.EDU> Sent: Wednesday, February 06, 2002 5:20 PM Subject: Re: [PIC]: Newbie Q. re: electrical outlet and SSR > on 7/2/02 7:32 AM, David VanHorn at .....dvanhornKILLspam.....CEDAR.NET wrote: > > Hey Dave, > > > Black is the "hot" lead, and is the one that you should interrupt. > > In a series circuit, from an academic point of view, it does not matter, > > but from a safety point of view, I should never be able to touch a white > > wire that is hot. (loads of things violate this, but that's how it should be) > > As an Australian and too young to remember anything OTHER than a 3-wire MEN > system, I am curious about the US 3-wire system. Is the White leg > (equivalent to what we term a neutral, I assume) connected to Earth at some > point in the building's electrical system or is it floating? > > ie; in a new building with 3-wire outlets throughout, is the white neutral > leg tied to earth back at the distribution board? Where I live in Quebec there are three wires coming off the transformer on the utility pole. The earth wire is connected at the utility box with a fat bare copper multistranded cable to the earth via the house plumbing or a copper rod driven into the ground. I assume the white wire is grounded at the pole, but it may just be the neutral side of a three-phase transformer...dunno. > > Also is the colour coding still Black, White and Green? The Green/Yellow > combination is not used? I have never seen green/yellow except inside appliances like electric lawn-mowers. > > I lived in Taiwan for about 8 years, and they STILL use what I assume to be > a copy of the OLD 2-wire US System - One white and one black. I can tell you > I never trusted either of those suckers and made sure there was a dual pole > isolation switch between me and the nearest power station at all times - > then checked with a meter just to be sure! :-) In my current apartment most of the wiring is cloth-covered and looks brown but when it was installed about 50 years ago it may have been colour-coded. I have seen in the basements of other peoples' houses the remains of the original electrical system: two cloth-covered wires about a foot apart running on ceramic insulators. No earth ground... /\/\/\/*=Martin -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

At 09:20 AM 2/7/02 +1100, Sean Alcorn - Avion Sydney wrote: >As an Australian and too young to remember anything OTHER than a 3-wire MEN >system, I am curious about the US 3-wire system. Is the White leg >(equivalent to what we term a neutral, I assume) connected to Earth at some >point in the building's electrical system or is it floating? > >ie; in a new building with 3-wire outlets throughout, is the white neutral >leg tied to earth back at the distribution board? Yep - in 2 places (redundant): inside the meter box (usually on the outside of the building) and inside the main disconnect (usually part of the main breaker panel). The meter box earth - neutral connection is accomplished by stripping the insulation from the neutral conductor and clamping under a robust ground clamp. The main disconnect accomplishes the same thing by having a screw connect the neutral bar to the case. The neat thing about the meter box neutral ground is that you don't cut the neutral in order to ground it; in fact, the neutral must be a continuous (no splices) conductor from the service connection to the disconnect. The bonding screw inside the disconnect is removable for those cases where the panel is used as a sub-panel being fed the main panel but must NOT be removed if the panel is in fact the main panel. >Also is the colour coding still Black, White and Green? The Green/Yellow >combination is not used? I'm now starting to see green / yellow wire instead of solid green in modern line cords. In addition, when we build and wire racks to be used in industrial plants, we are allowed to use green / yellow in place of solid green. I assume (but don't know for a fact) that at some point all ground conductors with insulation will be green / yellow. dwayne Dwayne Reid <EraseMEdwaynerspam_OUTTakeThisOuTplanet.eon.net> Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax Celebrating 18 years of Engineering Innovation (1984 - 2002) .-. .-. .-. .-. .-. .-. .-. .-. .-. .- `-' `-' `-' `-' `-' `-' `-' `-' `-' Do NOT send unsolicited commercial email to this email address. This message neither grants consent to receive unsolicited commercial email nor is intended to solicit commercial email. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads