American System Voltages?

sparkstation; the USA started out with 25 cps (hertz) with the hydro power at Niagara falls, New York, the building my dad had his office in also had 120 volt D.C., where some radios burned out or would not work until you reversed the 2 prong power plug. perry

Hello Guest,

Thank you for your clarification re the above.

The US did start with DC as supplied from Thomas Edison's generators.

Niagara Falls Power

Rankine Generating Station - (produces 25 cycle power) this power station is currently not producing as a result of an agreement with Ontario Power Generation.

The battle for electric supply and distribution was fought fiercely, but Tesla's polyphase AC system won the day, refer: http://en.wikipedia.org/wiki/War_of_Currents

Interestingly enough, the town of Reefton in New Zealand's South Island, is that it was the first town in New Zealand and the Southern Hemisphere to receive electricity, back in 1888, refer: http://en.wikipedia.org/wiki/Reefton

Kind Regards....

Suffice it to say, there are dozens of voltages, frequencies, and numbers of phases that have been used, and will be used in the past, and tend to die slowly. We still have two phase customers out there that are reluctant to change.

Add to the history column the one-upsmanship that happened for 40 years, with utilities, suppliers, consultants, and construction companies trying to out due one and other by completing the latest, highest voltage transmission line, and you leave a mess as a legacy.

Growing forward, most American utilities strive to comply with the standard voltages defined in the standard ANSI/IEEE C84.1.

I would like to reverse the question. Why do we, in the USA, have 120VAC as our single phase house type appliance voltage, and most of the remaining world has 230VAC? Do these other countries enjoy making idiots who stick a fork in a receptacle, as I did when I was just 2 years old, pay with their life for being stupid? 120VAC gives you a nice tingle while 230VAC kills you out right.

When it comes to the modern safety devices we now have, my Mother always said - "when I was a child, if you were stupid, you died."

Here in 'Murrica we use bigger volts, that's all.

It is obvious that the reason you survived your encounter with the outlet is that you have an insulated brain and an ungrounded butt....if you had been well grounded, it would have done more than tingle. (hee hee hee!)

HTRN

Well, it's a bit more complicated than that - true, 230 VAC is more likely to kill than 120 VAC (but make no mistake about it - 120 VAC can kill!) - BUT, the higher voltage means that the currents in the circuit are lower - which means they are less likely to overheat - which means less likely to start fire - so it's a balance of fire vs. shock hazards - not an easy call. Plus the lower currents in teh 230 VAC systems mean they can use smaller conductors - which reduces cost of installation.

Andy - ajdonlan@rogers.com

Seems to me that heating is from voltage drop across a resistance, which is wattage, which is volt x current, and at the same fault resistance, 240 volts with 10 amps versus 120 volts with 20 amps is the same wattage. I don't see any reduction in heating potential in the higher voltage.

Now with the same size wire, yes, one can tamper with protective devices and force more current through on a 120 volt circuit easier than on a 230 volt circuit, perhaps what you were thinking of. People will be people, and they will do the same on either voltage with bad results. Besides that, the European wired devices we use here are always wired at least two sizes smaller than our good electrical manufacturing practices prefer here. We get motors wired with AWG 16 for currents under 10 amps, while we are told to NEVER wire a power circuit with less than 14 AWG and most of our customers specify 12 AWG as a minimum for any 120 volt or higher power circuit. House wiring is at least 14 AWG for 15A, 12 AWG for 20A. So, with smaller wire in Europe, you have defeated the heating arguement of the lowered current.

Whilst not recommended, I have easily survived many zaps with 120 volt. I do not wish to try the same at 230 volts.

Actually, the voltages selected for industrial, distribution and transmission systems are pretty much the same around the world. The voltages selected were based on the physical limitations of the insulator materials available at the time inside the generators and transformers.

We see 11 kV was very common in early systems worldwide. This gradually crept up to standard distribution voltage of 14 kV (or 13.8 to be more precise) with improvements to insulation levels. With greater need transmit power longer distances, much greater insulating materials were developed. Thrifty engineers would always try to specify the highest voltage available, as this would keep costs to a minimum. Of course, once an area's infrastructure was built at a certain voltage, it generally will stay at that voltage - hence the "mixed bag" of voltages over the years.

The differences in voltages in different systems are therefore more related to the date each was built, rather than the location in which it was built. This process is ongoing, as we now see a trend from 240kV transmission systems developed as the standard in the 60's and 70's to 500kV as the norm.

I'll never for the life of me know why the world ended up being split into the 50 Hz and 60 Hz domains. Voltages can always be transformed into something else, but the change in frequency really prevents one person's equipment from being used somewhere else.

To illustrate the cost differences voltages create - Canada was always the odd-man-out in the Americas because we used 600V equipment for medium voltage commercial and industrial applications, as opposed to the U.S. standard of 480V. For a small country like Canada this was a very limited market and not many manufacturers made equipment at 600V. However, the extra voltage reduces the cost of wiring by about 35%. This can result in $10-20 million dollars in savings on a typical refinery or industrial plant construction. Now, we are seeing a number of electrical engineers from the United States coming to visit the facilities we are building in Alberta, Canada, to incorporate such economics in their designs.

To further complicate life for us in the NE USA, there is some 550VAC equipment in use, or was in use, around Schenectady NY. Apparently GE generated their own unique voltage electricity at one time. We bought some of their machinery at an auction, and had to change all motors to 480VAC before we could use them.