Hello I'm from Europe, I wanted to talk a little about electric systems What is actually about using 120 volts in America and 240 volts for big appliances, because in Europe or Asia it is voltage over 200 volts like 230v for every appliance even with the lowest power and three phase 400 volts for big appliances. Do You think is this to high for households?, like for example for American conditions. Have You in America got a proplems with to low voltage when using for example hairdryers on 120 volts I,ve heard that breakers turn off when it's 2000 watts and like 20 amps, and how about very big houses (like in Hollywood ;-) Do the voltage falls down significantly? Regards

 

You need to deliver power, that is, voltage x current.

A 120V system has to deliver twice the current as 240V for the same power.
Modern homes in USA are wired for 100A service, that's 12kW. Older homes might be wired for 60A.
Most outlets are wired for 15A or 20A service. That's 2400W with 20A circuit.

Do voltages drop? Yes when equipment that demands large power turns on, you can see the lights dip but only for a fraction of a second. Household appliances, electronics and computers are designed to handle a small drop in voltage.

When you consider that most modern electronics run on 5-12-24VDC some new homes are being wired for 12VDC or 24VDC in order to eliminate all those wallwarts.

 

We were told that the US could afford the extra cost of thicker copper wiring needed for double the current consumption that occured by using 110 volts instead of 220 volts AC.

 

Hello,

I live in Holland and here we use 230 Volts @ 50 Hz.
My main fuse in my appartment is 30 Amps, so total power is 6900 Watts.
I have 5 groups in my home wich are fused by 16 Amps each.
I have no electric heating, but use a gas central heating with hot water supply.
I also use gas for cooking.

Here is an overview of the wiki about the different mains voltages in the countries around the world:
https://en.wikipedia.org/wiki/Mains_electricity_by_country

Bertus

 

Welcome to AAC!

Do You think is this to high for households?, like for example for American conditions.

Personally, I feel safer working with 120VAC than with 240VAC. I've seen people literally knocked off their feet when contacting 240VAC.

Have You in America got a proplems with to low voltage when using for example hairdryers on 120 volts I,ve heard that breakers turn off when it's 2000 watts and like 20 amps

Our typical circuit breakers are 15A and most hairdryers I've seen are 1000-1500W; so there is no issue when the hairdryer isn't run with too many other appliances at the same time on the same circuit.

, and how about very big houses (like in Hollywood ;-)

Size doesn't matter. Standard breaker sizes are still 15A. For higher current, they can use 20A, but the wire needs to be sized accordingly.

Do the voltage falls down significantly?

That's generally not a problem in developed countries and appliances are designed to work with the typical voltage variation.

 

The 120 VAC is households. In the US it's generally called single-phase, but I think it's better call split-phase.

The primary is single phase, but the secondary is center-tapped 240 V transformer with the center tap grounded,

The AHU/NEC (Authority Having Jurisdiction, National Electric Code) generally limits continuous loads to be 80% of the breaker rating and a 3% voltage drop. So, by design if the voltage drops, there is something wrong. "continuous" has a specific meaning.

In a home an electric water heater, clothes dryer dishwasher, air conditioner or dryer might be 240 VAC. Water heaters are likely 240 VAC. Clothes dryers can be 120 (typically gas) or 240. A dishwasher can be either. Central air is more than likely 240 VAC. We had a uge commercial window unit at one time that was 240 VAC.

There's some weirdness with dryers. The new code uses a 4-wire system where you have L1, L2, Ground and Neutral. All that's necessary to use the old outlets 3-wire outlets is a cable.

Some history: We used to have 2 pole non-polarized outlets, then there was polarized outlets with ground run to the metal box for safety, but not to the outlet and finally the 3 prong polarized outlets with 15 and 20 A varieties. Now, I think, two 20 A circuits is required in the kitchen and one in the bathroom.

The new codes are requiring AFCI's and GFCI's in most locations but you don't have to retrofit.

3 phase power is available in some jurisdictions for houses, in some locations.

==

We have typically have two different types of 3 phase for "normal stuff". Something called a high leg delta which gives 240 three phase and 125 V single phase and a 208 three phase Y type of system. There is a 277 VAC (480/sqrt(3) system that runs lighting only. In the lab I worked in, we had a lot of "plugged in stuff" that was 60 Amp three phase and 60 A single phase and some 90 A 3 phase @ 208V. One piece of equipment took an entire sub-panel feed of 200 A 3 phase 208 V.

The building infrastructure also had, I think 480 VAC 3 phase for 32 water to air heat pumps, the chiller and circulator pumps.The feed, to the building power room was something like 9.6 kV 3 phase.

 

Some history: We used to have 2 pole non-polarized outlets, then there was polarized outlets with ground run to the metal box for safety, but not to the outlet and finally the 3 prong polarized outlets with 15 and 20 A varieties. .

In N.A. the 15a and 20a duplex outlet has polarized sockets for two pin application if required.
One pin larger than the other.
Max.

 

On a side note and slightly related I had a conversation yesterday with a friend. They had recently spent some time in Sweden and Italy. During my younger years I worked and lived in Europe as well as living in Japan for about a year. Here in the US Americans for the most part are spoiled. This is especially true when it comes to electricity and more important what we pay for electricity. Currently here in Ohio we pay between five and ten cents per kilowatt hour and while cost across the US vary overall the cost of electricity is inexpensive. Fortunately we have an abundance of natural resources to produce electricity as opposed to for example Japan which has few natural resources to produce electricity. We discussed how in Europe, Japan and around the globe people are very conservative with electricity, especially in countries where they use electric heat during cold winter seasons.

Electric billing here in the US has a breakdown of the cost. Things like cost per KWh, delivery cost and other itemized cost on the bill but overall on a national basis electricity in the US is relatively inexpensive. The same is true for fuel like gasoline, even with the taxes.

Ron

 

We have 240V 50Hz in Australia too. My place is wired single phase and has a 50A main breaker.
I'm looking into getting 3 phase put on. It used to be very hard to do that for a home but now it is easier as more aircons are 3 phase.
Also I want to extend my solar power. At the moment I have 2 x 5KW units, (partly broken but that is another involved story), and I'd like to have 3 x 5KW, one per phase.
Across 2 x 240V phases (120 degrees out of phase ) you get 415V so for bigger current devices you can use the higher voltage single phase like a 415V welder.
And yes, the power in the US is very cheap. My wife come from Washington state and I was amazed at the low cost of power there.
And the fuel too!

 

Interesting reguarding voltage standards around the world. It's pretty easy to convert voltages so adapting is not so hard. The thing that I've puzzled over is the frequency standards. Last summer we were in Brazil which has a huge dam on the border with Paraguay. Of the 20 turbines, 10 on the Brazil side generate at 60hz and 10 on the Paraguay side generate 50hz. Even weirder some of the 50hz power is sold back to Brazil and converted to 60hz for local use.

I guess I'll have to do some research to find out how this whole 50/60hz mess got here. I know in the good old mainframe days IBM and CDC machines used motor generators to convert 60hz to whatever they needed (100hz?) but I'd like to know more about that.

 

ThankYou very much dl324 and everyone, for these explains

 

I asked actually about American haidryers on 120v, but how about hairdryers on 240v split phase, do You think is that possible?

 

If you get an Australian hair dryer it is 240V. So are some from many other countries. They work quite well.
Just don't run a 110V one on 240V unless you want a paint stripper, very briefly before it becomes a smoke generator!

 

If you get an Australian hair dryer it is 240V. So are some from many other countries. They work quite well.
Just don't run a 110V one on 240V unless you want a paint stripper, very briefly before it becomes a smoke generator!

So You use in the U.S. the 240v outlets in the bathrooms sometimes?

 

I'm in Australia and on my visits to the U.S., didn't use a hair drier so no, I don't.
If you have a 240V outlet and a 240V hair drier where ever you are, they should play together ok.
BUT, most of those outlets in the hotels could be low power, just for shavers, so I'd check before you try to use a drier on them to see what the power capability of the outlet is, and if it can handle the consumption of the drier.

 

I'm in Australia and on my visits to the U.S., didn't use a hair drier so no, I don't.
If you have a 240V outlet and a 240V hair drier where ever you are, they should play together ok.
BUT, most of those outlets in the hotels could be low power, just for shavers, so I'd check before you try to use a drier on them to see what the power capability of the outlet is, and if it can handle the consumption of the drier.

Oh sorry I forgot You wrote before, that You are from Australia, and thankYou for this explain. I'm pulling that topic again because I've been growing in "200 volts country" ;-) and this is interesting that USA stand by lower voltage and it's still ok, meanwhile rest of the world wanted to change to higher, because of wire diameters, but America has the biggest power use and large buildings. I wish to have lower voltage in the house also because of costs because American appliances have visibly lower power use, and the distribution between the buildings is based on voltage on level like 7200 volts when for example in Europe it is only that 3-phase 400v actually, sometimes on long distances. You wrote about house supply in Australia, that You often 1 phase, and in many european countries (except Great Britain probably) when the stuff is over like 3500 watts is rated for 400v only, because the wires are very thin. I think 3 phases are good only for motors because they can spin on windigs in circle with the natural move of motor, it's called probably Power of Electromotoric Rotation but also multipolar direct current is good for that. Regards

 

So You use in the U.S. the 240v outlets in the bathrooms sometimes?

I've never seen one in a bathroom.

We use 240VAC for high wattage appliances like stoves, dryers, air conditioners, water heaters, and well pumps. Some things are hardwired and some things have receptacles.

 

I saw something about this yesterday. American electricity was decided in an argument between Tesla and Westinghouse starting with the idea that Edison already had a DC system in place. I wouldn't be surprised if it was on this site.

 

I saw something about this yesterday. American electricity was decided in an argument between Tesla and Westinghouse starting with the idea that Edison already had a DC system in place. I wouldn't be surprised if it was on this site.

Yeah, I know that history very good, but I'm new on this site so I didn't see it here, and I'm just asking about it, because that system 230/400v proposed for global standard by International Electrotechnical Commission is actually ..... primitive a little, because it's over 200 volts even for smallest appliances, and in the U.S. it's used only for high wattage stuff and not even for all. In America are specialized parameters of energy for specific appliances, for example for computers and audio systems is balanced split phase 2 x 60v = 120v, (transformed from 2 x 120v), You use generators, transformers, frequency converters and much more often the direct current, and in Europe it all is not common (everything is simplified to send 3ph 400v on long distances and minimalized, the old wires are very thin so easy to damage and then You have open 200v, but from the other side if You have big sizes of conductor it's actually waste of money), many NEMA plugs configurations which makes unable to plug 120v connector to 240v receptacle f.exmpl., so I just wanted to know some practice here about that 120v system. Regards

 

Do You know maybe the american practices about using the motors for saws, when You want to change the direction of rotating of the saw, what is the often solution in America when You don't have three phase system, is that multi-magnet motor which makes the natural rotation? Is that rather DC or AC single phase?, or maybe just electric generator whith 3 phases