Yes, we do have 240VAC 60Hz here in the USA. But it's provided as a pair of 120VACs, in other words, 240VAC centertapped to ground/earth.
My local power company transfoirmer:

This in turn feeds my house and then a few vintage Aussie style American 3 pin outlets/power points. These happen to use the same physical pattern as the Aussie power point outlets, and exactly accepts Aussie plugs. Though here both slanted pins will be hot. But my Aussie radios all use power transformers, so that won't matter. And 50Hz power transformers are perfectly happy with 60Hz. They have more iron core than they need for 60Hz. Only if there's a clock motor or phonograph record player would there be a problem with 50 vs 60Hz.







These predate WW2, and were around since at least 1915. Our current 3 pin grounded outlets, which accept our regular parallel blade 120V plugs, were invented after WW2.

Figured you'd find this of some interest.

I like the scary skull-like design of those old plugs. In Australia we had a home safety cartoon which played this up, "They're Gonna Get You!"

Yes, it's interesting to find that our style of outlet, which became the national standard around 1938/9, was an American invention dating to 1915:

http://patimg1.uspto.gov/.piw?Docid=1179728&idkey=NONE.

Interesting that it didn't catch on in the USA, but then there are so many NEMA formats anyway.

The pins on Australian plugs are about 2mm shorter for safety reasons but apart from that everything is identical, including the pattern of the wall boxes. Australian socket and switch mechanisms made by Ring Grip, Wilco and Clipsal between the 1930s and 1980s were almost identical to the ones shown above.

Pictures of these to come.

Pictures of a typical Australian pole-top substation and 11kV to 240/415v street aerials to come too.

American pattern polarised and non-polarised sockets get used here too, although as special purpose outlets rather than for everyday use.

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A valve a day keeps the transistor away...

"Interesting that it didn't catch on in the USA"

I think that the Aussie pattern outlet, which was usually wired for 120VAC on the slanted pins (though I have mine wired for 240VAC to operate my Aussie radios, they have dual ratings, 120V15A and 240V10A, and UL approved), didn't catch on because it couldn't accept the older NEMA 1-15 2 pin parallel American plugs. Later on, after WW2, our American grounded outlets, NEMA 5-15 were introduced and these can accept the old NEMA 1-15 2 pin plugs. NEMA, established after WW2, grandfathered the 2 pin parallel plug, but not the Aussie pattern, thus no NEMA designation for it.

"Pictures of a typical Australian pole-top substation and 11kV to 240/415v street aerials to come too"

Looking forward to seeing those. Does each home get just one phase of 240VAC, or do they get 415V also?

"Does each home get just one phase of 240VAC, or do they get 415V also?"

These days the typical residence is single phase 240v (or 230v officially as it is since Oz adopted "harmonized" voltage nomenclature).

When I was a kid it was not unusual to find older houses with 2 phase supplies (two actives plus a neutral) to accommodate the inefficient 2 phase stoves, ovens and water heaters of the era.

I still see the occasional house fed with two actives and a neutral from the street.

The service supply fuse (from memory) is around 60 to 80 amps per phase. This may have increased over the years.

Factories and those with large motors, etc, get 3 phase (415v) as required.

Our street lines have 3 phases x 240v plus neutral strung between poles (sometimes with 11kv strung above it) so the supply company just hooks up to those 240v lines without the need for an individual transformer in most cases, except where the customer has a heavy current demand in which case they will get a transformer (sort of a mini substation) either on the pole, or on the ground tapped onto the 11kv supply.

The usual single phase house connections are spread across the street line phases to balance the loads.

In heavy industrial areas things are usually different with the distribution poles having more high voltage lines and with supply company substations occupying the space of an average residential lot situated in the area and tapping off EHT lines of up to 132kv.

I'll also try to get some photos of various pieces of the network infrastructure without appearing to be a local rep of al qaeda.

Modernization and under-grounding will make supply arrangements in some suburbs different from others, so my info is possibly out of date for the more modern estates, nonetheless it remains that the typical residence is single phase 240v.

Within the residence, power and light are run from different circuits from the meter board. There will be typically a couple of 8 amp light circuits and two or three 15 amp power circuits, with the power outlets rated at 10amps (although a special 15amp outlet with a wider earth pin is available).

My 3 bedroom house (built 1980) has this fused circuit configuration from the meter board:

Power outlets 3 x 15 A
Lights 1 x 8 A
Wall oven 1 x 28 A
Hotplates 1 x 20 A
Hot water service 1 x 15 A

(all the above is single phase 240v).

Both fixed light and power circuits these days are 3 wire (active, neutral and earth). Going back a while, light circuits were simply active and neutral. I forget when the 3 wire rule came in.

In configurations that I am familiar with, the common earth link and the common neutral link at the meter board are connected to a grounding source (water supply or grounding stake). I think that's a national standard but am not sure.

Before the 1970's a house was generally wired with a single phase if it was also connected to the gas mains for stove and hot water. Houses with electric stove and hot water were either single phase or two of three phases or all three phases, depending on where you lived and the size of the house. It is not uncommon for Victorian and Federation era houses to be served by three phases though the consumer's aerials (wires between a pole and the house) were 4mm², and 10mm² consumers mains whereas a modern installation with a single phase service will have 16mm² consumers mains and rated at 100 amps, which is big enough to support an average domestic installation.

In the outback the Single Wire Earth Return (SWER) system is more common - a single 11kV bare wire with a small substation (about the size of the one in your photo) located near the residence it serves, lowers the voltage to 240 volts. If three phase is required in such areas it is getting more common to run an inverter.

For clarity, just before the Sydney Olympics, there was an agreement between the states and territories to set a new uniform nominal voltage for Australia. The nominal voltage, as dictated by AS60038, is now 230 volts rather than 240 however like most interstate agreements nothing was ever done to bring the system inline with the policy and it is still quite normal for upto 250 volts to be available at the powerpoint. This is probably because of the tolerance allowed by the Standard, to wit, +10% and -6%. I mention this only to satisfy any curiosity members and guest have if they bump into a copy of the Standard.

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A valve a day keeps the transistor away...

Perth used to have 254V mains, and it was terrible for imported 220V European-designed appliances, which were usually sold without modification other than replacing the mains plug.

I just noticed that my copy of the SAA Wiring Rules is dated 1981, so I'm a bit behind, LOL!

Okay, I put the camera in the car and looked out for examples of low, medium and high voltage supply delivery methods.

Here is a typical street distribution pole in Sydney. Looking at the cross bar, the insulators from right to left hold the 240v lines for Phase C (blue) , Phase B (white), Phase A (red) and Neutral (black). Neutral is closest to the footpath (sidewalk).

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The single wire running atop the pole is usually for street lights, but the light on this pole is wired across the general supply and I think that is because it is self-switching via a light sensor.

The catenary cable running beneath the light is hybrid fibre-coaxial (HFC) for TV, phone and broadband internet for those who want it via cable.

The 4 thick insulated cables running down the pole and underground provide 3 phase + neutral to a "kiosk" style substation on private property, such as this one ...

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... which supplies a block of apartments.

Here is an aerial 3 phase feed to a private property:

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Here is a pole-mounted substation, in the form of a transformer, dropping 11kv to 415 three phase plus neutral:

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And a more modern one:

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Atop this pole is very high voltage distribution to large regional substation. This one is (I think) 132kv, or maybe 66kv or 33kv ... a liney could tell by the insulators:

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Some poles can get very busy and unsightly ..

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... so in some areas, particularly where there are lots of trees, tightly bundled cable is used. Here, naked 3 phase plus neutral 240v comes in on the left of the pole, and leaves as TBC on the right:

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... and here is how it is tapped off for the consumer:

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... and hits the house thus:

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And a 3 phase line into an older style house:

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Otherwise, houses are fed like this:

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.. or like this (note the earth taken off the neutral for the mounting pole):

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On streets with underground power, which is the norm for new estates, you see junction pillars like these:

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Here is an example of multiple earth neutral wiring. (We use black to denote neutral). In this instance it is a control hut for a mobile phone tower:

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On my rounds, I noticed quite a few new dwellings with 2 phase plus neutral, and it struck me that is possibly to support ducted air conditioning which is very popular nowadays. Or maybe split dwellings (granny flats) with separate metering.

Tomorrow, I may take a few shots of a regional switch centre on the grid. (That ought to have ASIO create a file on me, LOL!)

Sue: "Perth used to have 254V mains, "

I think it was 254v on a good day. I've had numerous battles with Western Power over the years concerning voltage surges. We experienced a number of (literally) blown up UPS units which we had inspected by the manufacturer and they laid the blame squarely on long duration surges above 254v.

It was a farce. Western Power blamed the shopping centre owners and the shopping centre owners blamed Western Power.

That's the sort of thing I heard about, complains about exploding appliances. And the allegation that higher voltage meant higher profits for the company because of the power wasted.

I remember when WA's supply of new light globes were marked 250v instead of 240v.

I am not so sure about the yarn about power being wasted though. The higher the voltage, the more efficient AC is to transmit and there is also a saving on the gauge of transmission cables. The higher the voltage for a given load, the smaller the gauge can be. That said, there's little gain to be made in this area by increasing the potential difference at the powerpoint by 20 volts. The difference here would be more due to the long standing tradition in Australia where each state did its own thing.

Up until around 1989 Sydney still had DC mains going through the CBD to run lifts and moving footways. There was also a time when the AC mains frequency in parts of New South Wales was 40Hz. Some of AWA's Radiolettes were made with larger transformers to accomodate the lower frequency.

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A valve a day keeps the transistor away...

Up until around 1989 Sydney still had DC mains going through the CBD to run
lifts and moving footways.

Basslink, the undersea national grid connection between TAS and VIC is 400kV DC.

Okay, here are some pics of substations.

This is a major transmission substation, with a zone substation attached. The towers contain the 330kv transmission lines from the NSW grid that extends into QLD and VIC:

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Various feeds to the street at 11kv:

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And 132kv or 66kv or 33kv to other zone substations:

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... such as this one:

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Basslink is DC for a fairly good reason - DC is more efficient to transmit than AC because there are fewer electrical losses. What DC lacked until the advent of the solid state control circuitry on Basslink was an easy way to raise and lower the voltage. On Basslink, and perhaps future mainland lines, is some pretty large transistors powering the various inverters.

Good pictures of the transmission lines. There's another to add - the 500kV line running between Eraring Power Station on the Central Coast of NSW and Kemps Creek, west of Sydney.

Transgrid's map of the State's high voltage network shows this is more detail. See pages six and seven.

I spent part of today getting some pictures of wall sockets, switches, switchboards and power lines and will grab more at the weekend before publishing them all.

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A valve a day keeps the transistor away...

Yes, DC avoids the skin effect problem, and it also provides a neat way to avoid frequency synchronization problems when bridging AC networks.