House Wiring (was: [OT] Batteries)
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From: Peter D. on 14 Oct 2007 09:46 on Saturday 13 October 2007 10:13 in the Usenet newsgroup alt.os.linux.mandrake Adam wrote: > Peter D. wrote: [snip] > I don't know much about this and hope someone will correct me, but as I > understand it, your typical American house has two 110-120V feeds out of > phase. The entire house is wired for 120V (plug has vertical prongs > plus ground pin). Somehow the two feeds are combined to get 220-240V > (plug has horizontal prongs plus ground pin, or sometimes circular > prongs), but that's only run to the few places where 240V appliances > would be, typically the range (stove/oven), clothes dryer, and larger > air conditioners. I was assuming each house had a street supply of 220V and a transformer with a single phase 110V output, but a two phase system could be used. I am not the man to ask about US power supply techniques. >> Yes that is the folklore I was repeating. The low voltage was >> chosen for good electrical safety, at the expense of poor fire >> (and overall) safety. > > What may be of slight interest was the choice of AC over DC in the U.S. > From http://www.richard.clark32.btinternet.co.uk/chair.html : > > "In the 1880's, electricity was a new and novel power source. Thomas > Edison and George Westinghouse were the two major players in the > struggle to control electrical utilities. Technical and economic > circumstances made Westinghouse's alternating current superior to > Edison's direct current. Alternating current was soon adopted as the > standard for electrical transmission worldwide. Edison had tried to > convince everyone that Westinghouse's AC current was unsafe and was > delighted when New York State introduced the electric chair, which > required alternating current." [snip] Legend has it that Edison wanted people to say that criminals were "Westinghoused", rather than electrocuted. For marketing reasons. -- sig goes here... Peter D.
From: Peter D. on 14 Oct 2007 09:49 on Saturday 13 October 2007 10:43 in the Usenet newsgroup alt.os.linux.mandrake Robert M. Riches Jr. wrote: > On 2007-10-13, Adam <look(a)bottom.for.address> wrote: >> >> I don't know much about this and hope someone will correct me, but as I >> understand it, your typical American house has two 110-120V feeds out of >> phase. The entire house is wired for 120V (plug has vertical prongs >> plus ground pin). Somehow the two feeds are combined to get 220-240V >> (plug has horizontal prongs plus ground pin, or sometimes circular >> prongs), but that's only run to the few places where 240V appliances >> would be, typically the range (stove/oven), clothes dryer, and larger >> air conditioners. > > Right. The "somehow" is the feed coming into the house is > essentially 220V with a center tap. Center tap, implies a transformer. 220V single phase on the supply side, and 220V (plus centre tap) on the user's side? > The two outer lines are > called L1 and L2. The center tap is called N, for neutral, > and it is grounded at building entrances. (That's where the > power lines enter the building, not at the doors.) L1 and > L2 have 220V between them. L* and N have 110V between them. > Safety ground is routed separately from N, because N at an > outlet can be a few/several volts above ground, enough to > taste wild if one were to hold onto one and stick one's > tongue on the other. > -- sig goes here... Peter D.
From: Unruh on 14 Oct 2007 18:28 "Peter D." <psd(a)live.home.invalid> writes: >on Saturday 13 October 2007 10:13 >in the Usenet newsgroup alt.os.linux.mandrake >Adam wrote: >> Peter D. wrote: >[snip] >> I don't know much about this and hope someone will correct me, but as I >> understand it, your typical American house has two 110-120V feeds out of >> phase. The entire house is wired for 120V (plug has vertical prongs >> plus ground pin). Somehow the two feeds are combined to get 220-240V >> (plug has horizontal prongs plus ground pin, or sometimes circular >> prongs), but that's only run to the few places where 240V appliances >> would be, typically the range (stove/oven), clothes dryer, and larger >> air conditioners. >I was assuming each house had a street supply of 220V and a transformer >with a single phase 110V output, but a two phase system could be used. >I am not the man to ask about US power supply techniques. Nope, each house gets 220 volts swinging in opposite phases WRT ground. Thus by using ground ( a big copper rod driven 6 ft into the ground) you get two 110 volt outputs. If something goes wrong with the ground, you get a 220 running through the two phased 110 circuits in series.
From: Unruh on 14 Oct 2007 18:38 "Peter D." <psd(a)live.home.invalid> writes: >on Saturday 13 October 2007 10:43 >in the Usenet newsgroup alt.os.linux.mandrake >Robert M. Riches Jr. wrote: >> On 2007-10-13, Adam <look(a)bottom.for.address> wrote: >>> >>> I don't know much about this and hope someone will correct me, but as I >>> understand it, your typical American house has two 110-120V feeds out of >>> phase. The entire house is wired for 120V (plug has vertical prongs >>> plus ground pin). Somehow the two feeds are combined to get 220-240V >>> (plug has horizontal prongs plus ground pin, or sometimes circular >>> prongs), but that's only run to the few places where 240V appliances >>> would be, typically the range (stove/oven), clothes dryer, and larger >>> air conditioners. >> >> Right. The "somehow" is the feed coming into the house is >> essentially 220V with a center tap. No. The transformer is on the pole outside your and your neighbour's house. 600---- ---------------------- +110 S C S C________ S C - ___S C . | C______________________ -110 _ - . The two 110 lines come into the house with 220V between them. In the house you connect the neutral to ground. >Center tap, implies a transformer. 220V single phase on the >supply side, and 220V (plus centre tap) on the user's side? 600 or 2000 on the supply side. You know, that single wire way up at the top of the poles, with big glass conductors setting it off from the poles? (ground is the return path. Cheaper than copper). >> The two outer lines are >> called L1 and L2. The center tap is called N, for neutral, >> and it is grounded at building entrances. (That's where the >> power lines enter the building, not at the doors.) L1 and >> L2 have 220V between them. L* and N have 110V between them. >> Safety ground is routed separately from N, because N at an >> outlet can be a few/several volts above ground, enough to >> taste wild if one were to hold onto one and stick one's >> tongue on the other. >>
From: Peter D. on 15 Oct 2007 02:33 on Monday 15 October 2007 08:38 in the Usenet newsgroup alt.os.linux.mandrake Unruh wrote: > "Peter D." <psd(a)live.home.invalid> writes: > >>on Saturday 13 October 2007 10:43 >>in the Usenet newsgroup alt.os.linux.mandrake >>Robert M. Riches Jr. wrote: > >>> On 2007-10-13, Adam <look(a)bottom.for.address> wrote: [snip] >>> Right. The "somehow" is the feed coming into the house is >>> essentially 220V with a center tap. > > No. The transformer is on the pole outside your and your neighbour's > house. > > 600---- ---------------------- +110 > S C > S C________ > S C - > ___S C . > | C______________________ -110 > _ > - > . > > The two 110 lines come into the house with 220V between them. In the house > you connect the neutral to ground. Good ASCII art. >>Center tap, implies a transformer. 220V single phase on the >>supply side, and 220V (plus centre tap) on the user's side? > > 600 or 2000 on the supply side. You know, that single wire way up at the > top of the poles, with big glass conductors setting it off from the poles? No, I can't see it from here. My eyes are poor and I'm 8,000 miles away. ;-) > (ground is the return path. Cheaper than copper). [snip] That depends on local soil properties. It works very well in some places. -- sig goes here... Peter D.
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