Two phases to house - loss of neutral
in [Repair]
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From: Sylvia Else on 25 Nov 2009 20:32 D Yuniskis wrote: > Sylvia Else wrote: >> D Yuniskis wrote: >>> Have we decided that you really have two different *phases* >>> vs. two different *legs* (but really "single phase" -- think >>> center tapped transformer). >> >> Four wires on the power poles in the street, being a three phase >> supply. We have three wires leading from the street, and two power >> meters, plus a third meter for the off peak water supply. > > I'll ignore the comment about power meters as you can get > power meters with all sorts of internal topologies (i.e., > I can't deduce anything from that). > > So, does *your* house have "phases" A and B dropped to it; > your neighbor gets B & C; *his* neighbor C & A; the large > *business* at the end of the block A B & C, etc.? My neighbour appears only to have one phase. He commented to me that he remembered that the previous owner of my property had got a second phase installed, but didn't know why. Presumably the power company tries to balance phases. Sylvia.
From: D Yuniskis on 25 Nov 2009 21:14 whit3rd wrote: > On Nov 23, 5:38 pm, D Yuniskis <not.going.to...(a)seen.com> wrote: > >> Grounding the mains to "plumbing" *was* common in the US many >> years ago. Now, I believe, you *must* ground to a metal >> rod driven into the earth (8 ft?). > > Just to be clear, my copy of the US National Electric Code clearly > requires (section 250-80) plumbing to be bonded to the electrical > service ground, it just doesn't allow the buried water piping to > substitute for a ground rod or similar to-the-soil connection. Exactly. And the housing of the circulating pump for your swimming pool must be grounded as well. But, you don't ground the *mains* through your circulating pump! :> The Code tries to anticipate things that *could* become electrified and grounds them. E.g., exposed beams in a metal building, etc. But, it doesn't let you use those things *as* ground! > The ground wire from the interior water pipe grounds the pipes, not > the electric wiring. Exactly. However, in years (decades) past, it was common to use the water main as the ground for the incoming service. This isn't a reliable way to "earth" the mains (for a variety of reasons). If you poke around people's homes, you will see all sorts of "questionable practices" wrt ground. Its a wonder more folks aren't electrofried! :>
From: D Yuniskis on 25 Nov 2009 21:57 Sylvia Else wrote: > D Yuniskis wrote: >> Sylvia Else wrote: >>> D Yuniskis wrote: >>>> Have we decided that you really have two different *phases* >>>> vs. two different *legs* (but really "single phase" -- think >>>> center tapped transformer). >>> >>> Four wires on the power poles in the street, being a three phase >>> supply. We have three wires leading from the street, and two power >>> meters, plus a third meter for the off peak water supply. >> >> I'll ignore the comment about power meters as you can get >> power meters with all sorts of internal topologies (i.e., >> I can't deduce anything from that). >> >> So, does *your* house have "phases" A and B dropped to it; >> your neighbor gets B & C; *his* neighbor C & A; the large >> *business* at the end of the block A B & C, etc.? > > My neighbour appears only to have one phase. He commented to me that he > remembered that the previous owner of my property had got a second phase > installed, but didn't know why. So, this is a way of providing you with enough "supply" to match your needs? E.g., here, if you need more power, you upgrade your entire service. I.e., a 60A service might be upgraded to 100A; 100A to 200A, etc. In each case, all of the conductors coming into the house are increased to a higher ampacity. (you appear to be able to just "add another leg"?) > Presumably the power company tries to balance phases. OK.
From: Sylvia Else on 25 Nov 2009 23:14 Leaving the neutral failure issue aside, what would happen if I disabled the Earth leakage detectors and drew power across the two phases. Would the two utility meters correctly reflect the energy I consumed? Sylvia.
From: Sylvia Else on 25 Nov 2009 23:23
Sylvia Else wrote: > Leaving the neutral failure issue aside, what would happen if I disabled > the Earth leakage detectors and drew power across the two phases. > > Would the two utility meters correctly reflect the energy I consumed? > > Sylvia. On second thoughts, it's pretty obvious that they wouldn't be correct, and that I'd be significantly overcharged for the power. Sylvia. |