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Re: Grounding Rules in .au

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  • Jim Farrer
    Dear FM, I ve tried awhile, but can t visualize what you ve said. I thought I knew a few basics about 3 phase, but this is all new to me; always willing to
    Message 1 of 20 , Feb 29, 2000
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      Dear FM,
      I've tried awhile, but can't visualize what you've said. I
      thought I knew a few basics about 3 phase, but this is all new to
      me; always willing to learn. My address is 8 Carter Court,
      Rockville, MD. 20852-1005, and I'd appreciate the info you
      mentioned in your previous post.

      The idea of a multitap transformer with just one tap: is this a
      secondary with a tap at midpoint?

      You mention "resistance," but do you mean an actual resistor in
      the transformer (which would entail a *great* amount of heat
      loss, or did you mean "inductive impedance?"

      If you meant midpoint tap, then one could be placed on ONE of the
      three phases, and this could be grounded. But connecting such a
      midpoint on the other two phases to ground would, I believe,
      result in no little fireworks.

      I need to see your circuit.

      Jim

      fmstark@... wrote:

      > From: fmstark@...
      >
      > jim yes the wye design is as you state, the delta also
      > but.......... envision
      > that one of the coils is a multitap transformer with only one
      > tap! soooo 3
      > hot legs and a ground!!!! a 4 wire delta electrical system.
      > (KEYWORD
      > multitap) look at a schematic that shows a muti-tap trans with
      > one tap, you
      > have a resistance on either side of the ground /neutral
      > (thought i had
      > mispelled that earlier DUH! LOL) so envision "one leg" as the
      > the multi tap
      > and here is the kicker the grd/neut does not have the same
      > resistance on
      > either side of it; hence any possible combination of voltages.
      > Have you ever
      > heard of the wild leg or stinger leg mentioned when a delta sys
      > is being
      > discussed? that is why i mentioned 179/277volts as well as the
      > usual
      > 115/230/460v sys. used in the US, and i believe US is also a
      > MEN muti earth
      > ground/neutral sys. as well. hope this helps! regards fm
    • Wallace Edward Brand
      Dear Jet Black, 240 volts times 100 amps = 24 kva and assuming 100% power factor, enough capacity to supply a load of 24 kw from the primary distribution
      Message 2 of 20 , Feb 29, 2000
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        Dear Jet Black, 240 volts times 100 amps = 24 kva and assuming 100% power
        factor, enough capacity to supply a load of 24 kw from the primary
        distribution system. In this country, I think the standard service has been
        100 amps at 110 volts and 220 volts with most of the load served at 110
        volts. It would therefore seem that either you Australians use more power on
        average than we do, or else, without my knowledge, our standard services are
        now of greater capacity. I did hear a rumor from someone to the effect that
        the standard service in this country is now 200 amps. When I built my house
        in 1964, only a 100 amp service was offered. I wanted 300 amps but settled
        for 200 and I am now sure glad I got more than 100 amps. The reason I am
        interested in this subject is that Plug Power, a fuel cell company whose
        product is to be marketed worldwide by GE, commencing in 2001 is to be
        producing and selling a fuel cell system that will deliver up to 7 kw
        continuous and a 3 hour peak of 10 kw from battery storage, and will handle
        surges up to 15 kw. This will be great for places in the outback remote from
        any grid. But will the capacity be great enough?

        Jet Black wrote:

        > From: Jet Black <blackj@...>
        >
        > excuse the length , I raised a lot of questions hence a lot of answers....
        >
        > I just got off the phone to a friend with a bit of rank & a lot of
        > experience with the local supply co, who gave me a rundown of the high
        > voltage distribution system here , he also commented on the similarities &
        > differences between the US & Oz elec supply systems , especially each house
        > having its own split transformer is very different to here.I'll go back
        > upline a bit to explain how we get 240V to each house.
        >
        > The power supply co has numerous "kiosk's" installed in each "zone" through
        > Sydney
        > Each kiosk has an underground 3 phase + neutral (pretty sure) 11Kv feed
        > into it where it is stepped down to 415 volts (phase to phase) via a delta
        > ---> star transformer.The star transformer as Jim mentioned has a neutral
        > join in the center with a winding for each phase coming off it.The earth
        > and neutral are bonded at these transformers & the transformers along with
        > its steel enclosure have a local earth stake (somewhat bigger than a
        > domestic one) the resistance between neutral & earth at these kiosks is
        > less than 1/2 ohm , there are many _many_ kiosks in each a zone , the
        > neutral wire remains common/bonded through each zone.The neutral is not
        > common between zones.I'll be getting a some maps & technical info on the HV
        > and low voltage distribution setups for my local area in a day or so
        > <woo-hoo!> so I can post some figures about zone areas and capacities. For
        > Oz readers the kiosks are those green boxes you see at ground level usually
        > between the pedestrian footpath & the side of the road, approx size is 4ft
        > wide by 5ft high & 15feet long , I would not advise 'opening' the lock to
        > have a look inside of them unless you have a serious deathwish.
        > Distribution out of these kiosks is via overhead wires in old areas &
        > underground in new areas , all that comes out of them is 3 actives @
        > 240Volts and a neutral , fmstark has upped the general aol users
        > intelligece quota through the roof with his "root2 x 240 = 415Volts"
        > thoughts ,100% correct , the only "real" supply voltage we get here is
        > 240Volts the 415Volts is obtained across any 2 phases.
        >
        > Reguarding getting a neutral out of a Delta transformer here , an isolation
        > transformer is used to create a false neutral of sorts, usually called
        > a "zig zag" transformer , we didn't discuss them too much , they don't
        > seem to be that common.I imagine the line diagram for one would help
        > explain it's name.
        >
        > Normal supply for a domestic installation is 240Volts @ 100 amps , a bigger
        > supply or more phases usually needs justification to the supply authority.
        >
        > Reguarding the legalities of "exploiting" the neutral & earth wires to get
        > power , my contact was unsure about it (mostly because he had never heard
        > of it happening), but at a glance it seems doing it here could possibly
        > upset or bypass the power co's metering ,normal people messing with the
        > meters is bad thing (tm) , it's even worse if they catch a licenced
        > electrician doing it , goodbye licence , hello surverlence & monitoring for
        > eternity .
        >
        > Jim was also correct about the plumbers electrocution , unless they put a
        > battery jumper cable across both sides of a pipe they are cutting (for
        > earth continuity) they unwittingly become a conductor when they grab both
        > sides of the open ended pipe.I have heard similar stories about some
        > electrical supply authority contractors who have somehow cut a kiosk's
        > earths in two then casually grabbed an end with each hand to re-join
        > it.Most end up being thrown 10 to 20 feet away in a random direction , if
        > they live through it they don't do it again in a hurry.
        >
        > I think that covers most questions...
        > The essence of the white earth project is to have your own earth somewhere
        > on your property & compare it's potential difference between the various
        > other earth
        > (or higher) potentials in your house , when I started this I burnt out 2
        > multimeters trying to monitor what I was getting , using a cheap 8 ohm
        > speaker will let you "hear" the power and variations much easier &
        > cheaper.At the moment I have 2 seperate earth stakes setup with 2 "D class"
        > speakers to place across the arrangement.
        > The D class speakers (sub-aural) have some interesting specs , 3 ohm
        > internal coil resistance , 18 watts RMS power & rated @ 20 foot pound ,max
        > torque.
        > If you think the specs are weird you should see/hear/feel what happens when
        > I put them across a white earth & grid earth here , _very_ odd.
        >
        > JB
        >
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      • Jet Black
        excuse the length , I raised a lot of questions hence a lot of answers.... I just got off the phone to a friend with a bit of rank & a lot of experience with
        Message 3 of 20 , Mar 1 5:55 AM
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          excuse the length , I raised a lot of questions hence a lot of answers....

          I just got off the phone to a friend with a bit of rank & a lot of
          experience with the local supply co, who gave me a rundown of the high
          voltage distribution system here , he also commented on the similarities &
          differences between the US & Oz elec supply systems , especially each house
          having its own split transformer is very different to here.I'll go back
          upline a bit to explain how we get 240V to each house.

          The power supply co has numerous "kiosk's" installed in each "zone" through
          Sydney
          Each kiosk has an underground 3 phase + neutral (pretty sure) 11Kv feed
          into it where it is stepped down to 415 volts (phase to phase) via a delta
          ---> star transformer.The star transformer as Jim mentioned has a neutral
          join in the center with a winding for each phase coming off it.The earth
          and neutral are bonded at these transformers & the transformers along with
          its steel enclosure have a local earth stake (somewhat bigger than a
          domestic one) the resistance between neutral & earth at these kiosks is
          less than 1/2 ohm , there are many _many_ kiosks in each a zone , the
          neutral wire remains common/bonded through each zone.The neutral is not
          common between zones.I'll be getting a some maps & technical info on the HV
          and low voltage distribution setups for my local area in a day or so
          <woo-hoo!> so I can post some figures about zone areas and capacities. For
          Oz readers the kiosks are those green boxes you see at ground level usually
          between the pedestrian footpath & the side of the road, approx size is 4ft
          wide by 5ft high & 15feet long , I would not advise 'opening' the lock to
          have a look inside of them unless you have a serious deathwish.
          Distribution out of these kiosks is via overhead wires in old areas &
          underground in new areas , all that comes out of them is 3 actives @
          240Volts and a neutral , fmstark has upped the general aol users
          intelligece quota through the roof with his "root2 x 240 = 415Volts"
          thoughts ,100% correct , the only "real" supply voltage we get here is
          240Volts the 415Volts is obtained across any 2 phases.

          Reguarding getting a neutral out of a Delta transformer here , an isolation
          transformer is used to create a false neutral of sorts, usually called
          a "zig zag" transformer , we didn't discuss them too much , they don't
          seem to be that common.I imagine the line diagram for one would help
          explain it's name.

          Normal supply for a domestic installation is 240Volts @ 100 amps , a bigger
          supply or more phases usually needs justification to the supply authority.

          Reguarding the legalities of "exploiting" the neutral & earth wires to get
          power , my contact was unsure about it (mostly because he had never heard
          of it happening), but at a glance it seems doing it here could possibly
          upset or bypass the power co's metering ,normal people messing with the
          meters is bad thing (tm) , it's even worse if they catch a licenced
          electrician doing it , goodbye licence , hello surverlence & monitoring for
          eternity .

          Jim was also correct about the plumbers electrocution , unless they put a
          battery jumper cable across both sides of a pipe they are cutting (for
          earth continuity) they unwittingly become a conductor when they grab both
          sides of the open ended pipe.I have heard similar stories about some
          electrical supply authority contractors who have somehow cut a kiosk's
          earths in two then casually grabbed an end with each hand to re-join
          it.Most end up being thrown 10 to 20 feet away in a random direction , if
          they live through it they don't do it again in a hurry.

          I think that covers most questions...
          The essence of the white earth project is to have your own earth somewhere
          on your property & compare it's potential difference between the various
          other earth
          (or higher) potentials in your house , when I started this I burnt out 2
          multimeters trying to monitor what I was getting , using a cheap 8 ohm
          speaker will let you "hear" the power and variations much easier &
          cheaper.At the moment I have 2 seperate earth stakes setup with 2 "D class"
          speakers to place across the arrangement.
          The D class speakers (sub-aural) have some interesting specs , 3 ohm
          internal coil resistance , 18 watts RMS power & rated @ 20 foot pound ,max
          torque.
          If you think the specs are weird you should see/hear/feel what happens when
          I put them across a white earth & grid earth here , _very_ odd.

          JB
        • fmstark@aol.com
          JB thanks for compilment i rememered 1.73 as a constant couldnt remember where from sq root2 aHHHHH!!! thanks for the memory jog, but probably a miss type
          Message 4 of 20 , Mar 1 11:13 AM
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            JB thanks for compilment i rememered 1.73 as a constant couldnt remember
            where from "sq root2" aHHHHH!!! thanks for the memory jog, but probably a
            miss type sq root of 3=1.73 a lot of times the kiosk's also can have "line
            jacks" in them (a term used in trade US for automatic giant cicuit brk)
            {protects the entire grid by dropping a zone where there is a percieved
            problem} a dead short/too much demand /surge(lighntning) can cause these LJ's
            to trip. ever notice, power normally on then off/on/off/ if power doesnt
            stay on LJ will trip open (no power) and like a circuit breaker it will
            require a lineman to reset it! this happens very quickly (not sure how
            quickly between) on/off cycles but thru experience (i live in lightning
            capital of the world) usual if power rapid on/off 3 times and then off til
            manual reset. this story is long but.....

            i
            mentioned perceieved problem NOTICE if you happen to be at the end of the run
            and are experiencing low voltage, motors burn out (but wire size is correct
            for amps as well as distance) or motors run slow, or just sit and hum (that
            hasn't been already overamped slightly burned but still operational an
            motor) then 9 times out of 10 it is the LJ's (bad contacts). i know this for
            a fact!!!! as an a/c tech i was getting a reading of 189 volts using two
            different meters, both fans (indoor and out) were running slow, the
            compressor was already out on thermal overload (low than desgn voltage=High
            amps which creates heat), as a junior tech, had never heard of this happening
            to a whole system (to one fan motor yes, all the time one leg grounded motor
            speed slow) but whole system, call to office, response you got bad meters, i
            took lunch (which was a run to supply house) bought new meter came back, got
            same readings, called office and say BULL S#@%$%#$#@ about me having
            cheap/broken/uncalibrated meters, bought new one, same readings demanded that
            they CALL FPL (local elec. supplier), fpl tells office that a/c sys the
            problem but will check it out, i go on to other calls, later that day at the
            office i am "chewed out" by the service mgr, "for telling dispatcher what to
            do" if it happens again "the door will hit ya were the lord split ya"!!! next
            morning i am sent out to find the problem only to find a/c operating properly
            voltage/amps/pressures eveything great!!! call office they are dumbfounded,
            are you sure you are at the right place and the normal bull you get when you
            are considered a junior tech DUH!!!!!!!!!!!!!!! even if you are right all you
            get is DUH!!!!!!! well go on to next call, we will send out an experienced
            tech, he will find the problem, VERY PISSED OFF i load up and just about to
            leave, when a small car drives up, a guy gets out with meter in hand and goes
            to service panel does a check, gets into car and starts to leave, i stop him,
            find out he works for FPL and tell him what has happened, the whole story,
            and that my job is in jeopardy, he informs me that FPL nor he will admit hat
            it was fpl's fault (legally they would have to pay for the service calls, due
            to not providing what they say they do "clean power") but...... a short
            discussion concerning "line jacks" follow and (again i am reminded that there
            was no problem here) i get the message!!!!! I go directly to office and
            start berating service mgr. enough that he starts to call police, owner comes
            in, both sides tell the story (so she could decide whether or not i am
            fired), owner tells service mgr, that i am the 3rd tech from our co. to go
            there, that the customer has been having problems for over 6 months and that
            we havent been the only a/c company out there trying to figure out the
            problem,coustomer is threatning to sue, thank you STARK you will now be
            considered a senior tech, raise of 1/hr including this week's pay, more pay
            increases to follow "i cant afford to lose another tech", and i have a few
            other problem customers i want you to go see now!!! i will rearrange schedule
            go now, but please dont scream any more!!!!!!!!! i look at service mgr. his
            eyes go to floor, 3 weeks later he and his assistant are gone!!! THIS IS
            FACT:::::: > END OF LINE VOLTAGE PROBLEM, AFTER A COMPLETE/THROUGH
            INSPECTION and everything checks out the line jack is going to be the problem
            !!! PS if you have a refrigeration /air cond/ heat
            problem or want advice on best system to insall or if you think your being
            ripped off feel free to ask, i am a FL STATE CERTFIED hvac/r contractor,
            scored a 96 on the technical and last i heard florida was the hardest state
            to test for when hvac/r is concerned, too many ripoff artist's used to come
            down here for the winter oopen a shop and try to scam the people, then split,
            before the temp got to hotand customer realizedthey had been ripped off
            REGARDS, FM
          • fmstark@aol.com
            forgot i had paint brush very crude but iwill send it if this doesnt help regards fm[Unable to display image] cool it worked fm
            Message 5 of 20 , Mar 1 11:31 AM
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              forgot i had paint brush very crude but iwill send it if this doesnt help
              regards fm[Unable to display image] cool it worked fm
            • fmstark@aol.com
              wall ce sevice panels are rated residential at 220v only not 110v therefore 220x 100 =22kw, homes built now min.code 200 so fires are not as prevalent due to
              Message 6 of 20 , Mar 1 11:36 AM
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                wall ce sevice panels are rated residential at 220v only not 110v therefore
                220x 100 =22kw, homes built now min.code 200 so fires are not as prevalent
                due to user from overloading service panel causing building to burn ,fm
              • fmstark@aol.com
                sorry know a lot of things but operating systems i am quite lax lets try this an attachment [Unable to display image] [This message contained attachments]
                Message 7 of 20 , Mar 1 12:45 PM
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                  sorry know a lot of things but operating systems i am quite lax lets try this
                  an attachment [Unable to display image]


                  [This message contained attachments]
                • David Knaack
                  From: ... this ... so each of the drawn coils is the low voltage side of a transformer, handling one phase of a 3 phase
                  Message 8 of 20 , Mar 1 1:33 PM
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                    From: <fmstark@...>
                    > sorry know a lot of things but operating systems i am quite lax lets try
                    this
                    > an attachment [Unable to display image]
                    <snip drawing>

                    so each of the drawn coils is the low voltage side of a transformer,
                    handling
                    one phase of a 3 phase system?

                    DK
                  • Jim Farrer
                    [This message is not in displayable format]
                    Message 9 of 20 , Mar 1 4:03 PM
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                      [This message is not in displayable format]
                    • fmstark@aol.com
                      that is my understanding, the placement of the ground/nuetral would determine the odd voltages available fm
                      Message 10 of 20 , Mar 1 10:27 PM
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                        that is my understanding, the placement of the ground/nuetral would determine
                        the odd voltages available fm
                      • Jet Black
                        I m not firing on all 8 cylinders atm , please bear with my mistakes and contradictions & general lack of clarity untill I can sort the problem out :) ... In a
                        Message 11 of 20 , Mar 2 5:53 AM
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                          I'm not firing on all 8 cylinders atm , please bear with my mistakes and
                          contradictions & general lack of clarity untill I can sort the problem out :)

                          >From: Wallace Edward Brand <webrand@...>
                          >
                          >Dear Jet Black, 240 volts times 100 amps = 24 kva and assuming 100% power
                          >factor, enough capacity to supply a load of 24 kw from the primary
                          >distribution system.

                          In a new installation the incoming load is protected by a supply authority
                          100 Amp HRC Fuse , these "service" fuses in general don't blow out that
                          much , from memory a 0.9 power factor or better is the desired reality of
                          the system.

                          >In this country, I think the standard service has been
                          >100 amps at 110 volts and 220 volts with most of the load served at 110
                          >volts. It would therefore seem that either you Australians use more power on
                          >average than we do, or else, without my knowledge, our standard services are
                          >now of greater capacity. I did hear a rumor from someone to the effect that
                          >the standard service in this country is now 200 amps. When I built my house
                          >in 1964, only a 100 amp service was offered.

                          Some of the old Federation style houses I 've worked on had a 2 phase
                          supply (for the stove) with 60 or 80 Amp service fuses , my 60+ year old
                          house has a single phase 80 amp service fuse , I suppose the service fuse
                          rating is not really a true indication of our power consumption , I 'm
                          checking a 1981 rule book atm , there is an example on how to calculate the
                          "maximum demand" for various installations
                          A single phase domestic installation 64.3Amps
                          A "balanced" 3 phase domestic installation 38.9A , 33.9A , 34.7A
                          A block of 80 units approx 524.8 amps/phase
                          These are probably a more realistic usage figure for a house with an
                          electrical supply , a single phase house that has a natural gas supply
                          would drop some 22 amps or so in the maximum demand calcs.
                          Ahhhh, we seem to have overlooked some global positioning & cultural
                          differences.
                          Household heating and cooling is mostly done by electrical appliances here
                          , which may be different to the US , our houses have no basements with
                          furnaces in them , just huge reverse cycle air-conditioning systems.From
                          experience I'd say the weather in the south pacific is generally hotter
                          than the US , I didn't find Vegas all that hot when I visited it.
                          Remember , I inhabit an island roughly as big as the US mainlandwith a
                          population the size of Texas (< 18 million ) living mainly around the coast

                          > I wanted 300 amps but settled
                          >for 200 and I am now sure glad I got more than 100 amps. The reason I am
                          >interested in this subject is that Plug Power, a fuel cell company whose
                          >product is to be marketed worldwide by GE, commencing in 2001 is to be
                          >producing and selling a fuel cell system that will deliver up to 7 kw
                          >continuous and a 3 hour peak of 10 kw from battery storage, and will handle
                          >surges up to 15 kw. This will be great for places in the outback remote from
                          >any grid. But will the capacity be great enough?

                          Country people are used to doing it tough ,a quiet continuous 7Kw would
                          welcome to compliment their existing solar/diesel generator setup.Solar
                          power (despite continuous research) just can't deliver enough current on
                          it's own. I have heard a few "horror stories" from people in semi-remote
                          places in _Sydney_ on the prohibitive cost of getting hooked up to the grid
                          , so the market would not be limited to the outback.If people want more
                          power they will have to buy a pair of batteries I suppose.
                          There is also the fact that in the state of Queensland their electrical
                          grid is on the verge of overloading each summer , in a few more years it
                          will fail , plus the engineers designed their power grid in a way that they
                          could not import electricity from other states , the state that paints
                          itself into a corner with regular monotiny, many years ago they adopted
                          narrow guage railway lines while the rest of the country chose wide guage
                          rail lines , weird people , must be the heat......
                          I haven't checked the plug power site recently for prices & specifications
                          but having the Oz dollar is at 61 cents US & falling, might make the cells
                          fairly expensive when you add shipping costs , another concern of sorts is
                          how well they can handle our harsh climate , do they work well in a place
                          where it is often 40 degree's Celcius in the shade in summer ?

                          No wonder I can pick up all sorts of weird signals & power from the ground
                          , we appear to be a country full of wasteful electricity junkies ;)

                          JB

                          Dept of corrections:
                          > > Each kiosk has an underground 3 phase + neutral (pretty sure) 11Kv feed
                          > > into it where it is stepped down to 415 volts (phase to phase) via a delta
                          > > ---> star transformer.

                          I don't know how they get a neutral off the 11Kv delta side of the
                          transformer , everything else is right.

                          > > Reguarding getting a neutral out of a Delta transformer here , an isolation
                          > > transformer is used to create a false neutral of sorts, usually called
                          > > a "zig zag" transformer , we didn't discuss them too much , they don't
                          > > seem to be that common.I imagine the line diagram for one would help
                          > > explain it's name.

                          They must be common , idiot , every kiosk has one , that will teach me to
                          half guess about things I haven't worked on.A real answer when I have the
                          line diagrams in front of me :)
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