120 and 220? - Electronic Circuits Projects Diagrams Free

bootstrap's_bootstraps · 10th June 2005, 03:03 AM

here where i live (brazil) and europe they use 220-230 volts. in north america it is 120. why do they use different voltages?

mahinda jayasinghe · 10th June 2005, 04:02 AM

I belive it is expensive to maintain 120V electrical network, than 220V network. But 120V is much safer than 220V. USA and other oil rich countries are using 120V sypply.

Morgen · 10th June 2005, 06:32 AM

http://www.straightdope.com/classics/a3_292.html
I don't think oil has much to do with it.

williB · 10th June 2005, 06:51 AM

i wouldnt consider us oil rich .
an oil rich country actually HAS oil under their country .
we on the other hand have to purchase it..

**Jay.slovak** · 10th June 2005, 08:59 AM

Quote:

Originally Posted by bootstrap's_bootstraps

here where i live (brazil) and europe they use 220-230 volts. in north america it is 120. why do they use different voltages?

This is just only a historic issue. Back in Edisons and Teslas times, they competed which technology is better (AC or DC), And the voltages didn't chage until novadays.

Styx · 10th June 2005, 09:20 AM

Quote:

Originally Posted by mahinda jayasinghe

I belive it is expensive to maintain 120V electrical network, than 220V network. But 120V is much safer than 220V. USA and other oil rich countries are using 120V sypply.

The UK is oil rich, we are in the black for oil atm and we use 230V.
just a convention a country chose, the same with the freq

if you look at it UK worked on 240V and EU worked on 220V, we now harmonise at 230V, but hte UK still outputs 240V, its just appliences have a voltage tolerance

**Nigel Goodwin** · 10th June 2005, 10:46 AM

[quote="Styx"]

Quote:

Originally Posted by mahinda jayasinghe

if you look at it UK worked on 240V and EU worked on 220V, we now harmonise at 230V, but hte UK still outputs 240V, its just appliences have a voltage tolerance

Yes, the UK altered the tolerance figures, everyone else is something like +/- 5% - the UK is something like +7% -3% (these aren't the exact figures, just to give an idea of what was done). This allowed the UK not to make any changes to the infostructure.

BTW, the safety aspects of 120V vs 240V don't make a sensible reason for the difference, as I understand it, deaths by electrocution in the USA are no lower than in 230/240V countries. However, from what I've seen on TV (good old Norm 8) ) the wiring practices in the USA leave a lot to be desired?, so perhaps that makes it higher in the USA?.

Pyroandrew · 10th June 2005, 11:48 AM

The wiring practice have been tightened again recently in the UK. On a death point, the two AC supplies are just as lethal as each other. You only need 120v DC to kill, and 50V AC to kill (at 50Hz). So both have more than enough "overkill" to a good job of polishing off someone.

What is interesting is that around 50Hz is the worst place to have to have it, 60Hz more so. Of equal voltages, 60Hz is more deadly than 50Hz, but they are both smack in the middle of the most dangerous electrical frequency region to humans, make it just 100Hz and you would need about 80V AC to kill, 200Hz about 90V, make it 10Hz and you need about 110V to kill. I don't think that the frequency of the mains was selected on a safety note, just like the voltage wasn't either.

It's all to do with what is the most efficient, only 28% of the energy generated actually makes it to our homes and is used for the intended use (UK figures), so minimising waste is a top priority. Just by making the loss 1% less you would produce 16million tonnes less carbon emissions a year in the UK.

**mechie** · 10th June 2005, 04:39 PM

Quote:

Originally Posted by Pyroandrew

The wiring practice have been tightened again recently in the UK.

And we are to get more confused very soon (so-called harmonisation)
The ancient colour code for our mains cable was :-
. Red =Live
. Black= Neutral
. Green = Earth
and still is for 'installation cables'

BUT we have used
. Brown = Live ( :!: an earthy-sort of colour?)
. Blue = Neutral
. Green/Yellow (stripes) =Earth
for flexible cables for ages now.

And now in the name of politics we are to change our three-phase cable colours :-
Old colours ...
. Red = phase 1
. Blue = phase 2
. Yellow = phase 3
becomes
. Brown = phase 1
. Black = phase 2
. Grey = phase 3
Nobody seems able to explain why - I guess it's just to employ bureaucrats

Quote:

Originally Posted by Pyroandrew

It's all to do with what is the most efficient, only 28% of the energy generated actually makes it to our homes and is used for the intended use (UK figures), so minimising waste is a top priority. Just by making the loss 1% less you would produce 16million tonnes less carbon emissions a year in the UK.

I'm not sure this isn't a bit misleading - the electricity industry is pretty efficient at transporting electicity, the wasteful bit is generating the stuff.
Both the UK and the US (and everywhere else :?: ) actually transport power at much higher voltages than your domestic 240v anyway.
The UK 'SuperGrid' runs at 400,000 volts (400kv) in order to keep the current as low as practicable - current generates heat, that is where most of the transport loss is.

I agree that only about 30% of the energy is delivered as electricity though - the rest is lost in the power station (depending on type)

Quote:

Originally Posted by Morgen

http://www.straightdope.com/classics/a3_292.html

I wonder if the likes of Parsons would agree with this article?
http://www-g.eng.cam.ac.uk/125/nofla...0/parsons.html
Also
http://home.frognet.net/~ejcov/ediswan.html
http://home.frognet.net/~ejcov/alfredswan.html
Not to mention a host of other nationalities

eblc1388 · 10th June 2005, 04:51 PM

Quote:

Originally Posted by mechie

Old colours ...
becomes
. Brown = phase 1
. Black = phase 2
. Grey = phase 3
Nobody seems able to explain why - I guess it's just to employ bureaucrats

From the IEE review I read that the reason is to "help" electricians with color blindness who cannot distinguish the old color.

Of course I love the old color. I think the change is totally unrealistic and if color is such an important part of the job and getting it wrong would kill, not oneself but others as well, then electricians should be tested for color blindness.

Why not? Would you like to ride on a plane whose pilot is color blind?

**mechie** · 10th June 2005, 04:55 PM

Quote:

Originally Posted by eblc1388

Quote:

Originally Posted by mechie

Old colours ...
becomes
. Brown = phase 1
. Black = phase 2
. Grey = phase 3
Nobody seems able to explain why - I guess it's just to employ bureaucrats

From the IEE review I read that the reason is to "help" electricians with color blindness who cannot distinguish the old color.

I can't wait to see matching traffic lights :roll:

JFDuval · 10th June 2005, 06:48 PM

Hello!

Quote:

Originally Posted by mechie

Both the UK and the US (and everywhere else Question ) actually transport power at much higher voltages than your domestic 240v anyway.
The UK 'SuperGrid' runs at 400,000 volts (400kv) in order to keep the current as low as practicable - current generates heat, that is where most of the transport loss is.

Here in Quebec, its 735 000 Volts. Probably this is because electricity is producted far from the cities...

Styx · 10th June 2005, 06:58 PM

Quote:

Originally Posted by JFDuval

Hello!

Quote:

Originally Posted by mechie

Both the UK and the US (and everywhere else Question ) actually transport power at much higher voltages than your domestic 240v anyway.
The UK 'SuperGrid' runs at 400,000 volts (400kv) in order to keep the current as low as practicable - current generates heat, that is where most of the transport loss is.

Here in Quebec, its 735 000 Volts. Probably this is because electricity is producted far from the cities...

Damb!! you must have alot of ceramic/glass disks on yr pylons for that kind on potential, equally your main sub-stations must be fairly big as well

JFDuval · 10th June 2005, 07:02 PM

To this point, I cannot comment. I'm not aware of how big it is in others country. So, for me, what we have is normal

zevon8 · 10th June 2005, 07:54 PM

The thing about Hydroelectric power in Quebec, Canada, is that alot of it is generated in the James Bay area, so to get to say Montreal, it is over 1000 kilometers.

Some good info is here:
http://www.hydroquebec.com/visit/vir...transport.html

one of the substations is here:
http://www.hydroquebec.com/visit/vir..._radisson.html

100 football fields in size, transfering 6600 MegaWatts.

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10th June 2005, 03:03 AM	(permalink)
bootstrap's_bootstraps	120 and 220? here where i live (brazil) and europe they use 220-230 volts. in north america it is 120. why do they use different voltages?

10th June 2005, 04:02 AM	(permalink)
mahinda jayasinghe	I belive it is expensive to maintain 120V electrical network, than 220V network. But 120V is much safer than 220V. USA and other oil rich countries are using 120V sypply.

10th June 2005, 06:32 AM	(permalink)
Morgen	http://www.straightdope.com/classics/a3_292.html I don't think oil has much to do with it.

10th June 2005, 06:51 AM	(permalink)
williB	i wouldnt consider us oil rich . an oil rich country actually HAS oil under their country . we on the other hand have to purchase it..

10th June 2005, 11:48 AM	(permalink)
Pyroandrew	The wiring practice have been tightened again recently in the UK. On a death point, the two AC supplies are just as lethal as each other. You only need 120v DC to kill, and 50V AC to kill (at 50Hz). So both have more than enough "overkill" to a good job of polishing off someone. What is interesting is that around 50Hz is the worst place to have to have it, 60Hz more so. Of equal voltages, 60Hz is more deadly than 50Hz, but they are both smack in the middle of the most dangerous electrical frequency region to humans, make it just 100Hz and you would need about 80V AC to kill, 200Hz about 90V, make it 10Hz and you need about 110V to kill. I don't think that the frequency of the mains was selected on a safety note, just like the voltage wasn't either. It's all to do with what is the most efficient, only 28% of the energy generated actually makes it to our homes and is used for the intended use (UK figures), so minimising waste is a top priority. Just by making the loss 1% less you would produce 16million tonnes less carbon emissions a year in the UK.

10th June 2005, 07:02 PM	(permalink)
JFDuval	To this point, I cannot comment. I'm not aware of how big it is in others country. So, for me, what we have is normal __________________ JFDuval jfduval --@-- aqra.ca http://www.aqra.ca

10th June 2005, 07:54 PM	(permalink)
zevon8	The thing about Hydroelectric power in Quebec, Canada, is that alot of it is generated in the James Bay area, so to get to say Montreal, it is over 1000 kilometers. Some good info is here: http://www.hydroquebec.com/visit/vir...transport.html one of the substations is here: http://www.hydroquebec.com/visit/vir..._radisson.html 100 football fields in size, transfering 6600 MegaWatts.