Two phases to house - loss of neutral

Have we decided that you really have two different *phases* vs. two different *legs* (but really "single phase" -- think center tapped transformer).

E.g., 3 phase "220" (US) is three conductors plus a ground. If you look at any two of those conductors (ground referenced) you would see a 120 degree PHASE lag between them.

A US residential service is "single phase, 220" in which you have two 110V circuits ("legs") 180 degrees out of phase with each other (i.e., the center tapped xformer concept).

So, here, half of your lighting/living circuits are on one *leg* (so those appliances are nominally 110VAC) and the other half on the other "leg". Some bigger loads tend to straddle both legs (220) -- e.g., the blower motor in the evaporative cooler. Other appliances *use* both legs but actually as two 110V

*circuits* (i.e., higher ampacity available on two conductors).

(sigh) There seems to be a *lot* of vitriol in this group. Sad when you would *think* people were (supposedly) reasonably intelligent (?). Crappy S/N ratio! :>

--don

**You are, at this time, discovering the futility of asking a question that is specific to Australia, in an international group. Some very quick, informal examination of the houses nearby (about 50 or so) suggests that around 10% are single phase connected, another 20% are three phase and the rest are two phase. In my last home, the figures were more like 30% single phase, 10% three phase and the rest were two phase. The likely reason was that in my last home, town gas was available. At my present address, town gas is not available. There are also larger, more expensive homes where I live now and these people tend to have more power for various appliances like pool/spa heaters, big air conditioners et al.

I would hazard a guess that the majority of Australian homes are two phase connected. And, unlike the US, almost no domestic appliances (outside large air conditioners and pool heaters) use more than a single phase.

--
Trevor Wilson
www.rageaudio.com.au

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.

Sylvia.

Oh, I don't know. I've learnt a fair bit in the process.

Those in the US who really have a split single phase rather than two phases, would experience much the same effects if they lost the centre (neutral) link back to the transformer.

Sylvia.

US standard is 240 volts, not 220.

Yes we would, and it's a very exciting effect! ;)

If we want to be *pedantic*, there are LOTS of "little errors" in this discussion! ;-)

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.

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.?

I.e. what criteria are used to determine *who* is connected to *what*?

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!

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! :>

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"?)

OK.

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.

You can fairly easily identify whether you have a two legged single phase supply or two phases out of a three phase supply by measuring the AC voltage between the "phases".

If you get 2 x your single phase voltage you have a two legged single phase supply. If you get 1.73 x your single phase voltage you have two phases out of a three phase supply.

Thomas

yes.

No you wouldn't.

Each of the meters will indicate what you draw from the phases, and as you now have a higher voltage, you will also draw more power, which is what you are paying for.

Thomas

**Depends on the equipment you connected. The damage might range from mild to catastrophic. **Briefly, yes.

--
Trevor Wilson
www.rageaudio.com.au

"Trevor Wilson"

** TW has misread the Q.

It is only about how domestic watt hour meters respond.

** Indefinitely, actually.

.... Phil

My Yasnac/Yaskawa Acroloc CNC machine is supplied 3 phase 208 volts.

Sylvia Else Inscribed thus:

**********************************

I wasn't answering about two phase systems. Someone said he didn't know about the UK. That was the bit I was replying to.

--
Best Regards:
                Baron.