Not wanting to further hijack the chest type refrigerator thread I'll start a new thread.
I'm interested in the reasons people give for why a 220 volt powered appliance is necessarily (or not) better than a 110 volt application.
I've already heard that 220 use less power (watts), but Watts = Volts x Amps, so if you double the voltage (110 to 220) you just cut the amps in half. Our power company electric meters measure kilowatt-hours directly (not amps), so it seems there would be no electric cost savings whether you use 110 or 220.
Any thoughts?
wire is cheaper. with 220 you can run smaller gauge wire to deliver more watts at the end.
for example, a 20 amp 110 line will yield you 20*110 = 2200 watts
however, a 20 amp 220 line will yield you 4400 watts.
20 amp wire is 20 amp wire. you just need another one in the run for the other half.
http://www.houwire.com/products/technical/article310_16.html
If you needed 4400 watts in 220, you would use 20 amp wire - likely number #14 or #12
if you needed 4400 watts in 110, you need 40 amp wire, - like #10 or even #8.
-- aside from that I have heard that a 220 version will create less heat than the 110 counterpart but have no idea if this is a true statement. If something is generating heat it is loosing energy which would indicate inefficiency.
There would be no difference in power used comparing a 220 VAC appliance to a 110 VAC appliance if both were designed properly, which I think we must assume would be true. You are right in that at 220 VAC fewer amps would be conducted along the wires, but the watts would be the same. There would be a savings in the amount of wire used though, both in the supply lines and the actual appliance wires.
In this country the reason some things run on 220/240 VAC is related to the total power they consume. At 110/120 VAC the amperage drawn would be too high without impractical sized wires. I might be wrong, but I think once the USA settled on AC power instead of DC, we went with 110/120 VAC. As we developed more electrical devices we found that there was a point where it was better to make the appliance run on 220/240.
As for why does some of the world run 220/240 as its main supply voltage and others 110/120 I'm not certain. Maybe the wire cost? Maybe they learned from our "mistake" in selecting 110/120 as the primary voltage?
Maybe it was just done that way originally and once you start it's difficult to change. Sort of like left hand drive vs right hand drive automobiles. ??? Like why is some of the world 60 Hz and the rest 50 Hz?
220 , 222 whatever it takes eh d*
Little humor from the movie Mister Mom. :)
I believe the "use less power" argument came from how some power companies measured the used power. I believe it was an old wives tale. the concept being that 220 is actually 2 legs of 110. The wives tale came from the power company would just measure 1 leg and double it in the meter assuming the power was evenly divided. The "trick" was to determine which leg was being metered and switch all of your heavy usage 110V loads onto the leg that wasn't metered to "decrease the cost".
Anyway, that's what I heard. I am sure it's wrong because companies don't usually allow their money to be cheated out. But hey, it's a fund story.
Quote from: PEG688 on December 18, 2008, 11:50:53 AM
220 , 222 whatever it takes eh d*
Little humor from the movie Mister Mom. :)
I shall take this rare opportunity to correct PEG!!!! The quote was "220, 221, whatever it takes."
Woohoo, I shall revel in this moment for years to come. I'd like to thank all the little people who have helped me reach the top. ;D
Quote from: phalynx on December 18, 2008, 11:56:12 AM
I shall take this rare opportunity to correct PEG!!!! The quote was "220, 221, whatever it takes."
Woohoo, I shall revel in this moment for years to come. I'd like to thank all the little people who have helped me reach the top. ;D
Enjoy your moment of glory , I shall hope / do what I can to insure it is fleeting rofl
Quote from: phalynx on December 18, 2008, 11:54:34 AM
........ But hey, it's a fund story.
I got it, I got it! Clever!
You also deserve a prize. You beat Glenn to it!!! This truly is the season of miracles.
In general, appliances that draw over about 2000 watts are usually offered only in 240v, since they would require a dedicated circuit anyway, you might as well run a 240v circuit and get to use smaller wire. This is the case for electric water heaters, clothes dryers, and the like.
Sometimes though both voltages are available, and there can be efficency advantages to be gained by running on 240v as well as installation cost differences. A good example where a home builder may need to make the decicsion is electric heaters.
Lets look at one example. You need to install 1000 watts of baseboard heaters in a room, on a dedicated circuit with a 50 ft homerun to the panel. If you run this as 120v, you will draw 8.3 amps. On 240v, 4.2 amps. For either circuit you will need to run 14ga wire, no savings there. The 240v circuit will require a 2-pole breaker which is more expensive than the single pole breaker the 120v circuit would require. As far as operating efficency, your voltage drop in the 120v circuit would be 1.8% versus 0.5% voltage drop for 240v. This voltage drop is wasted heat. So the 240v circuit is 1.3% more efficient than the 120v circuit. This will pay back the cost of the extra circuit breaker in a short time.
For higher watt loads, or longer distances from the breaker panel, there are usually savings in wire cost when using 240v appliances since you have to upsize the wire more with higher current or longer distances to stay within the voltage drop requirements of the NEC.
Correct me f I am wrong, go ahead and line up PEG, but 240V isn't available in most US homes. The 220V that is installed is only 2 110V legs. You never actually get to use smaller wiring because the amperage is the same as a 110V circuit. You only get to double the amperage by adding in a 2nd 110V leg. It is true that running 220V over a single wire would be 1/2 the amperage of a 110V wire at the same wattage.
Phalynx,
Yes, it is available in almost all homes. Back in the very early days of electricity homes were wired with 30A 120V service but nearly all of these have already been upgraded. The code minimum service for a dwelling now is a 100A, 240V single phase service, and most average size homes are provided with 200A service based on load calculations.
I think you are confused about 220 versus 240. The nominal system voltage is 240V and 120V, I believe that is specified in the NEC. Of course this varies, in homes I have lived in it has tended to be in the 115-120 range. You would have to contact your electric utility to get their system voltage specs, but for the sake of discussion there is no difference between 110 and 120, or 220 and 240.
I don't understand what you mean by "the 220 installed is only 2 110v legs" as a reason for not using smaller wiring for a 240v circuit. On a single phase service, you are provided with two hots and a neutral. To supply a 120v load you wire between one hot and the neutral. To supply a 240v load, you wire between the two hots. The two hots are 180 degrees out of phase with each other so they "add up" in effect to 240v. That's how you get 240v from your residential service.
yes, 220, 240, and 208 all refer to the same thing. 2 legs of 110 power. There is no 240 line - that is the nominal value given just as 120 is the nominal value on what most call a 110 line. It steps up from there, a 480V is common in branch distribution and so on.
As for using another line for the 220 side, consider the difference between a 3 wire 110 run and a 4 wire 220 line. The extra conductor runs the other hot 110, but your neutral and ground are shared. It does come out cheaper to use 220 where you can because amps are amps. A 20amp 220 circuit would be a 40 amp 110 circuit so you can use 20 amp wire instead of 40 amp wire.
Hope that makes sense.
-- went to post and see cfabien beat me to it. what the hell, im posting mine anyway.
Correction to my earlier post - the standard that specifies 120V/240V as nominal system voltage is ANSI Standard C84.1.
This has been beat to death already, but as I look at the meters on the wall one is reading 120.8 V and the other is reading 120.6 and the third 241.5. There's a tenth of a voltage wandering around someplace, or the meters are off calibration. ??? Of course they actually fluctuate as things turn themselves on and off (or are turned on-off) and so on. This is measured right at the CB panels.
notice any warmth in those wires or meters? that's your lost voltage, that voltage drop is given up due to resistance in the conductor. a lightbulb works on the same principle. the energy is "lost" and given off as light and heat.
Since we're being technical, I must correct muldoon on one point.
A 208v circuit is not the same as 220/240. 208v is available only as part of a 120Y208 three phase service. It's a wye/star connected three phase service with 120v from each phase to a center neutral and 208V(120 * sqrt of 3) between each phase. Mostly used in office and commercial type buildings where there are a lot of 120V loads but due to setting and service size three phase service is preferred. You could conceviably tap two of the three phases and get a single phase 208v circuit, but I am not sure if there is much equipment made for this application. I worked for an equipment manufacturer once who made 240v single phase tools, and we had problems when a customer tried running them like this, on a 208v single phase leg of the three phase service they had available in their buildings. Three phase 208v equipment is pretty common though, for large loads in commercial settings (HVAC, elevators, etc).
Thank you cfabian, that makes sense. I wish I knew that a year and a half ago when I was in a meeting with a vendor and we were talking about requirements for datacenter work in a commercial building. The electrician was telling me there was no such thing as 220 in the building that he would give me 208. Fast forward a year and sure enough, he gives us 3 phase instead of the single phase 220-240 voltage my equipment needs. I did not realize the distinction.
To crosspost to another active thread, this is why I like it here. I learn everyday.
cfabian, by the way - welcome to the forum.
Thanks for the welcome. Been lurking here quite a while, two years at least. Keep quiet for the most part but electrical is my strong point. Unfortunately I haven't got a chance to build my dream cabin yet - maybe in the future.
Don, if the legs are not loaded equally and the 120's could read different. Seems the 10th is probably within the meter tolerances unless you are soon to have fire spewing from your wall.
We had a panel at Kathy's old house that was aluminum and had voltage loss- resistance heating and eventually destroyed the panel.
Seems you could take readings on the bus bars and the breakers and determine if there were bad connections. If reading on the same breaker and bar the resistance of the bad connection should give you a direct reading from the bar to the breaker connected to it.
Sorry Glenn, you're getting a tad too serious on this... my tongue was firmly planted in my cheek when I posted that in a hurry. Me bad. I should have used ::) ::) or something.
I've seen one leg drop several volts when something big comes on. It's especially interesting to watch when turning on the table saw and air compressor at the same time; drops as low as 103 from the nominal 120.
Let it be noted that over the years and in various places, the standard north american voltage has been, at various times, 110, 115, 117... but is now listed as 120.
With no house loads, other than phantom, we usually have 122-123. The transformer is not too far away.
I still say 222 will do [rofl2]
Mtn D's Little difference MTL is from his meter. We used Simpson 260's mainly while working on the jets ( EA-6B , Prowlers, USN ) I worked on, good meters. Then we transitioned to Fluke digital meters , junk , every time the ships radar swept the deck the meters would go nuts , about the time it would settle, the radar would sweep it again. I wonder if they ever worked that out. I also wonder what that radar did to a human body , not that I'd know d* being sort of super human in all :-[ :)
PEG, I used to work with Radar as well. We always said if your coffee was still warm 30 minutes later, someone forgot to turn off the radar!!
QuoteSorry Glenn, you're getting a tad too serious on this
rofl Sorry Don. Knowing how you like your numbers I thought you may actually have been concerned about the tenth.
I assume by New Years you will lighten up and only be concerned about a fifth. hmm
Hey everyone, been away for way too long and wanted to just check in and make sure everyone was doing ok????
I see Glenn is being his usual helpful self, Peg his usual masterful self and Mtn Don keeping all in order!!!
I must say that CFabien is a great addition to the crew and obviously knows electricity. Thanks so much for
everything you passed on CF and welcome to the crew!!
Well, I'm heading back to the lake tomorrow after turkey and Santa at my son's house in town. So here is wishing you all a very
Merry Christmas and a Happy New Year. What a great bunch of people. And good luck on all your projects!
Okie Bob
So nice of you to remember us and check in, BoB. [waiting]
As one of my great forum and personal friends, I'm hoping you have a great trip and time with your family and return to chat wit us ASAP. Great Holidays to you, family and all. :)