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dirknerkle
07-23-2009, 10:39 AM
Somebody help me out here...

I find it quite fascinating reading to discover how DIYC-ers around the world handle essentially the same issues yet on different power systems. :D

Why do some countries use 240 vs 120? Are there specific benefits that 240 provides that would cause a country to use it as their standard? Are there different scales of economy in providing a national power grid using one or the other? How many countries are DC only vs using AC? What special kinds of design/protective procedures do the 240v folks have to concern themselves with as opposed to the 120v folks?

This is truly a great, worldwide hobby!

toodle_pipsky
07-23-2009, 08:08 PM
I have a theory that it's the man trying to keep us down . . . . . there's the different power standards, then there's different wall plugs, then you got pal and ntsc, then you got regions 1 through 5 (i think) and 0/multiregion, then you got A4 and legal, then there's metric and imperial, then there's holiday and vacation, and verandah and porch . . . . . . but then McDonald's is global . . . . think about it. . . . . and if you fold a $10 note diagonally it says "all your base are belong to us". . . . . sorry what was the topic again? ;)

Sorry just being an idiot. That's a very interesting question - probably just to make it harder for people to take their toasters on holidays.
http://en.wikipedia.org/wiki/Mains_power_systems

Raindog
07-24-2009, 09:41 AM
Here is a crude explanation to some of your questions.

The main advantages of higher voltage were longer transmission distances, smaller conductor size for given power level. If you have to cost effectively move power over long distances higher voltages are your friend,

The disadvantage of higher voltages are demands of cable insulation, contact separation distances etc.

AC is used because it is readily transformed from high to low voltage. DC is easier to control and manipulate.

The reasons for adoption of different voltage standards by various countries are many and varied and as much to do with trade histories, bygone empires and the occasional world war as they are to do with any practical design requirement.

dirknerkle
07-24-2009, 12:33 PM
Here is a crude explanation to some of your questions.


Terrific posting - thanks! I wonder what specific techniques (if any) the 240v DIYC'ers use to keep things safe, and if that's any different from what 120v A/C folks use. Sounds like it some of it has to be different from the very start in the design phase.

jgrei1
07-25-2009, 02:58 AM
almost everything in australia we use is extra low voltage that is seperated from earth.. and also some 240v ropelights and things like that but they are all double insulated. and of course the use of gfci's is the law here.

WWNF911
07-25-2009, 04:07 AM
Here is a crude explanation to some of your questions.

The main advantages of higher voltage were longer transmission distances, smaller conductor size for given power level. If you have to cost effectively move power over long distances higher voltages are your friend,

The disadvantage of higher voltages are demands of cable insulation, contact separation distances etc.

AC is used because it is readily transformed from high to low voltage. DC is easier to control and manipulate.

The reasons for adoption of different voltage standards by various countries are many and varied and as much to do with trade histories, bygone empires and the occasional world war as they are to do with any practical design requirement.


Terrific posting - thanks! I wonder what specific techniques (if any) the 240v DIYC'ers use to keep things safe, and if that's any different from what 120v A/C folks use. Sounds like it some of it has to be different from the very start in the design phase.

I'll second that. Welcome to the forum Raindog. ;) For someone who's been lurking since Dec 2007, you've made a great contribution with your first post. And you can thank Dirknerkle for bringing you out of the closet. .... Well,...er.. uhh... so to speak. LOL

WELCOME!!!

Leon

synnie
07-25-2009, 04:46 AM
How do you fold that $10 note toodles?????

synnie
07-25-2009, 04:52 AM
Im curious about the 240/120 debate...i had to do a course on powerlines in regards to my job and they reduce it to 240/415V in Australia.Why dont they just go down to 120, or in other countries up to 240? Thats my 2 bobs worth

polar bear
07-25-2009, 08:43 AM
and i thought it was so we could hurt ourselves twice as quick, boom boom:rolleyes:

toodle_pipsky
07-25-2009, 10:17 AM
How do you fold that $10 note toodles?????
Stuff's me - I just wanted a reason to say "all your base". :) hehehehehehehehe

Lovin' Google. To add to the info raindog already gave
http://wiki.answers.com/Q/Why_are_different_household_AC_electrical_power_ma ins_voltages_and_frequencies_used_in_the_various_c ountries_around_the_world
It's all interesting - and still doesn't make sense to me. ;)

kostyun
07-25-2009, 10:35 AM
Why dont they just go down to 120.

Its a conspiracy to prevent cheap christmas lights!

Skunberg
07-27-2009, 12:48 PM
Here in the US most home have 120v for outlets, but also 220v for A/C, stove, dryer. If you look to commercial they use the these plus 440v, 600v, plus three phase to the mix. The lower the voltage the safer it tends to be, the higher voltage tends to be more efficient to use. I think that puts it into a nutshell without a long post. Brian

oldcqr
07-27-2009, 01:54 PM
A lower voltage does NOT make electricity safer. Amperage kills, not voltage. (Well... It's more complicated than that, but for the most part it is true).

Van de Graaff Generators (http://en.wikipedia.org/wiki/Van_de_Graaff_generator) create electric fields into thousands/millions of volts. Ever go to a science museum and see the demonstration of someones hair standing on end when touching a piece of metal? That's a whole lot of voltage with no amperage.

Many people equate higher voltage with higher lethality because in the US, typically higher voltage lines/equipment are designed to supply/use high amperage.

Side bar: The number of deaths due to 110V AC current in the US is actually HIGHER than 220V AC in say, Europe. That is due to the fact that the US uses 60 cycle power vs 50 in Europe. Why does that matter? 60hz is closer to the natural heart rhythm of a person than 50hz is. It is much easier for US power to disrupt the normal electrical discharge of the heart, making it more lethal. In the USA 60ma (.06A) of standard 110V power across the heart is enough to kill you (via Cardiac Arrest).

jasonhuff
07-27-2009, 05:09 PM
A lower voltage does NOT make electricity safer. Amperage kills, not voltage. (Well... It's more complicated than that, but for the most part it is true).

I know what your trying to say and its true. On the other hand, ill stick my hand in 120v if you will stick yours in 480v first?

oldcqr
07-27-2009, 07:49 PM
I know what your trying to say and its true. On the other hand, ill stick my hand in 120v if you will stick yours in 480v first?

480V with 0A? Ok. Heck, I'll even grab onto a 25Kv line, as long as the potential through me is 0 (the 'birds on a wire' trick). :cool:

WWNF911
07-28-2009, 02:29 AM
I know what your trying to say and its true. On the other hand, ill stick my hand in 120v if you will stick yours in 480v first?


480V with 0A? Ok. Heck, I'll even grab onto a 25Kv line, as long as the potential through me is 0 (the 'birds on a wire' trick). :cool:

Its true Jason. Its the amps that kills and it don't take much to stop your heart either.

hilight1173
07-28-2009, 04:41 PM
The number of deaths due to 110V AC current in the US is actually HIGHER than 220V AC in say, Europe. That is due to the fact that the US uses 60 cycle power vs 50 in Europe

Most European countries don't use a grounded neutral either, making it difficult to get shocked.

wjohn
07-28-2009, 07:30 PM
Why 240 VAC vs 120VAC?

Because of the egos of men.. (Toodle should like that).

Given that the standard organisations did not draft a IEEE document for domestic power reticulation, eack producer of equipment and services selected their own personal preference. From this free market approach, 120VAC, 220VAC and 240VAC were the dominant. Dont forget there were DC and AC services before standardisation.

Commonwealth countries generally went with 240 VAC, as our English forefathers exported their technologies from the UK to the Dominians of NZ, HK, AUS etc

Our European friends must have liked the UK 240VAC system, but the French hatred of all things British meant that they had to change it a little and call it 220VAC.

Our Friends in the US, well, you just like it your way ;-) Even with Market dominance, 110VAC is still only used in Countries geographically close to the US, or administrated by them at some point (Japan and Korea).

I wont start on the Metric vs. Imperial measurement system because somewhere someone will blow a valve. (just remember that there are only two countries in the world still using imperial measurements - One is the USA, and the other is broke)

220/240VAC is more effiencent than 110VAC (less copper in the cable for the same power rating). Both can kill.

Remember - this is just a post, not a thesis... ;-)

dirknerkle
07-28-2009, 09:47 PM
Remember - this is just a post, not a thesis... ;-)

Ahhhh.... but what a good post it was!!! Informative and entertaining at the same time. I think you get extra points for that :wink:

Thanks for the good info!

mrpackethead
07-29-2009, 05:59 AM
Why 240 VAC vs 120VAC?
Commonwealth countries generally went with 240 VAC, as our English forefathers exported their technologies from the UK to the Dominians of NZ, HK, AUS et


Mmm, in NZ we are 230V, 50Hz.. Not sure how the difference between 240V and 230V went across the ditch..

synnie
07-29-2009, 06:39 AM
Thats easy to answer MPH...that 10V difference is how much loss there is as the power cord goes across the ditch from Oz to NZ,that way when the last kiwi leaves NZ we can turn the power off instead...hehehehe

wjohn
07-29-2009, 07:17 AM
Ok,

we had to have one, and he is from the 'other' state of Australia.

I think what your are referencing to is AS/NZ2926-1987 which stated that the domestic supply voltage for Australia and our eight state was 240 VAC (+6/ -10%).

In 2000. AS/NZ2926 was 'harmonised' with the rest of the world. the new standard is 230 VAC (+10/-6%) . The math shows the the Upper and Lower limits are the same, just the label has changed.

In the US, the standard is 120VAC (+5/-5%), yet you will find references to 110, 115 and 117.

and for the record, 220 and 240 VAC fall within the standard AS/NZ2926 as part of the harmonisation protocol.

To para-phrase an ex PM of NZ, for every KIWI that returns to NZ, the collective IQ of NZ and AUS increases.

Matt_Edwards
07-29-2009, 07:18 AM
Why 240 VAC vs 120VAC?


.....

Remember - this is just a post, not a thesis... ;-)

Great piece.

Did you know? "As of 2000, the mains supply voltage specified in AS 60038 is 230 V with a tolerance of +10% -6%[3]. This was done for voltage harmonisation - however 240 V is within tolerance and is commonly found."
http://en.wikipedia.org/wiki/Mains_power_systems

I didn't know this. I am going to go and ask Integral Energy about this

Cheers
matt

Matt_Edwards
07-29-2009, 07:20 AM
damn I hate that.

toodle_pipsky
07-29-2009, 07:21 AM
Because of the egos of men.. (Toodle should like that).

I did say something about "the man". . . . I also mentioned imperial and metric. Ooooh it's a can of worms ;)

oldcqr
07-29-2009, 08:53 AM
... and I'll have you know that some of us Americans really want Metric. I'm sick of keeping 2 sets of tools around!:p

g2ktcf
07-29-2009, 08:57 AM
... and I'll have you know that some of us Americans really want Metric. I'm sick of keeping 2 sets of tools around!:p


No kidding! Would make engineering alot easier as well! :lol:

dirknerkle
07-29-2009, 01:32 PM
... and I'll have you know that some of us Americans really want Metric. I'm sick of keeping 2 sets of tools around!:p

I harken back to the old days of street racing when all you needed was a flat blade screwdriver, a vise-grips, a 9/16 wrench and some electrical tape and you could fix a Chevy... (sigh...) :(

rstehle
07-29-2009, 01:56 PM
I harken back to the old days of street racing when all you needed was a flat blade screwdriver, a vise-grips, a 9/16 wrench and some electrical tape and you could fix a Chevy... (sigh...) :(

Don't forget a big Crescent wrench and a 3/4" spark plug socket...........

dirknerkle
07-29-2009, 03:01 PM
Don't forget a big Crescent wrench and a 3/4" spark plug socket...........

So you have fond thoughts about the 'old days' too, eh?

synnie
07-29-2009, 03:32 PM
Oldcqr------you can never have too many tools:P

ErnieHorning
07-29-2009, 06:40 PM
... you can never have too many tools:PThatís what I tell my wife, every time I need just one more.:p

rstehle
07-29-2009, 08:03 PM
So you have fond thoughts about the 'old days' too, eh?

Oh Yeah! That's how I kept my '57 Chevy running................

(Had an old ammo case with my tools in it, kept it in the trunk in case of breakdowns......... none of the tools matched, but they worked.........)

wjohn
07-29-2009, 08:15 PM
Rebuilding a 1944 1/4 ton Jeep over the last year, I have had to learn all about UNC and UNF threads, #10,8 and 12 sized screws. And add to that 6 V auto systems with fabric covered wires!

Wayne J
07-29-2009, 09:20 PM
ehh, I really have no desire for the metric system. Decimal is just fine for me and what I do.

As for the old days, don't forget a matchbook to set the points gap. ;)

NORTHEASTER
07-29-2009, 09:51 PM
ehh, I really have no desire for the metric system. Decimal is just fine for me and what I do.

As for the old days, don't forget a matchbook to set the points gap. ;)

Don't forget for the Mopar lovers out there the spare firewall resistor you had to carry in your glove box that would fail at the worst possible time like when it is raining cat and dogs! I have a friend that worked for Sears appliance service centers back in the late 70's when Sears used Dodge vans. The firewall resistor was a mandatory stocked item on every service truck. Got to love those days!!

synnie
08-02-2009, 06:52 AM
[QUOTE=Wayne J;71570]ehh, I really have no desire for the metric system. Decimal is just fine for me and what I do.QUOTE]

Ummm..is there a difference between metric and decimal?

coolspot
08-02-2009, 08:58 AM
Most European countries don't use a grounded neutral either, making it difficult to get shocked.

doesn't make it any harder to get shocked as its the live that does it, not shorting the neutral and live

mrpackethead
08-03-2009, 03:22 AM
In 2000. AS/NZ2926 was 'harmonised' with the rest of the world. the new standard is 230 VAC (+10/-6%) . The math shows the the Upper and Lower limits are the same, just the label has changed.

and for the record, 220 and 240 VAC fall within the standard AS/NZ2926 as part of the harmonisation protocol.

To para-phrase an ex PM of NZ, for every KIWI that returns to NZ, the collective IQ of NZ and AUS increases.

Most interesting and informative. I'm glad our aussie cousins are now harmonized. I've often seen >230 on the wire. i was'nt aware that the voltage range was so great though.

230+ 10% = 253V, 230 - 6% = 217, so this a range of 217-->253V

dirknerkle
08-03-2009, 10:37 AM
Most interesting and informative. I'm glad our aussie cousins are now harmonized. I've often seen >230 on the wire. i was'nt aware that the voltage range was so great though.

230+ 10% = 253V, 230 - 6% = 217, so this a range of 217-->253V

"Harmonized?"

I think I got "harmonized" the first time when I was in college... it's all a blur and I don't remember a lot of it... :rolleyes:

WireWrap
08-05-2009, 11:48 AM
doesn't make it any harder to get shocked as its the live that does it, not shorting the neutral and live

When the neutral is connected to ground (earth), then connecting yourself from the live mains to earth is the same as going from main to neutral. When the neutral is isolated, there is less chance of a severe shock from the main to ground. Not to say the chance is eliminated, but it is reduced.