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115v vs 230v

L

lehmann

[H]ard|Gawd
Joined
Feb 8, 2005
Messages
1,362
As well know there is a little switch on our power supply's where we can chose either 115 or 230 volts. though i have never seen a 230v power supply cord? My under standing is that higher voltage is more efficient. Anyone have experience with this as i have no problem with the wiring. but is it worth it?
 
At work yes. We have some rack mount UPSs that put out 220/230, and the servers all automaticly switch to 230. All except the IBM terminal I plugged into it!!!! Now I have no terminal for the AS400 machine.... :( Made a nice POP though.

I also fried a few Dell monitors on those UPSs, so beware if you go that route. I've only seen this in a datacenter though, I doubt you would see enough of a gain at home to be worth it.
 
This is actually something interesting to consider considering that most homes already have several 220 volt circuits for the stove and dryer units. If one was going to add another circuit to power their folding farm, I wonder what kinds of efficiency gains you could get by running your entire fan with the PSU switched to 220volts. I was considering adding another circuit since my computer room is already maxed out when I have the window unit or space heater running, and it never ocurred to me that I could add a 220 volt circuit instead.
 
lehmann said:
As well know there is a little switch on our power supply's where we can chose either 115 or 230 volts. though i have never seen a 230v power supply cord? My under standing is that higher voltage is more efficient. Anyone have experience with this as i have no problem with the wiring. but is it worth it?
Click to expand...

You would have to check your specific power supply specs, but most are about 2-3% more efficient at 230V. So with a higher powered farm and expensive power, it probably would. The only problem is that I believe, technically, you need a licensed electrician to run a 230V circuit.
 
In the US the 220 V home outlets all have two hots leads and the difference between them gives you 220 volts. I am not sure how you would wire that up to a PC because it only has one hot lead connection. Like said above you will save a little if you can pull it off.

amdgamer You have a space heater in your computer room? Who needs a space heater in their computer room? Someone who needs more folding rigs.
 
You'll most likely need a transformer as most power supplies are wired for single-phase 110/220VAC. Most US homes are wired for single-phase 110VAC and split-phase 220VAC which wouldn't work. I don't know if it'll be worth it as any gains in efficiency would be offset by the transformer. Best route would be to ask a licensed electrician before experimenting. ;)
 
nwrtarget said:
In the US the 220 V home outlets all have two hots leads and the difference between them gives you 220 volts. I am not sure how you would wire that up to a PC because it only has one hot lead connection. Like said above you will save a little if you can pull it off.
Click to expand...

You just plug it in. It doesn't matter if one or both wires are providing voltage. All that matters is the difference in potential.

All you need to do is get a 220V circuit wired up, flip the switch to 220V (if there is one), and get a plug adapter to plug into a 220V outlet.
 
rmdashrrootsplat said:
You'll most likely need a transformer as most power supplies are wired for single-phase 110/220VAC. Most US homes are wired for single-phase 110VAC and split-phase 220VAC which wouldn't work. I don't know if it'll be worth it as any gains in efficiency would be offset by the transformer. Best route would be to ask a licensed electrician before experimenting. ;)
Click to expand...

It's actually single phase 240v that's split into two 120v circuits by center tapping the transformer on the pole. At the outlet, there is no difference except for potential. The sine wave between L1 and N for 120v is the same sine wave you'd see between L1 and L2 for 240v.

nwrtarget said:
In the US the 220 V home outlets all have two hots leads and the difference between them gives you 220 volts. I am not sure how you would wire that up to a PC because it only has one hot lead connection. Like said above you will save a little if you can pull it off.

amdgamer You have a space heater in your computer room? Who needs a space heater in their computer room? Someone who needs more folding rigs.
Click to expand...

If doesn't make any difference. two hots will behave exactly the same as a hot and neutral with regard to an AC electric circuit. L1 is 180º out of phase with L2, so while one is hot, the other isn't.
 
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Now here is my question. Are the two 120v leads joined at the psu plug, or are they both feed into the psu? (Neutral is on ground)
 
EngrChris said:
Now here is my question. Are the two 120v leads joined at the psu plug, or are they both feed into the psu? (Neutral is on ground)
Click to expand...

You cannot join both hot's together, you will create a short. With 240v, there is no neutral. Each hot has to go into a separate pin. You'll need one of these power cords (240v sockets are different depending on the amperage).
http://www.amazon.com/6-20P-C13-Pow...6?s=electronics&ie=UTF8&qid=1313504167&sr=1-6

or

http://www.amazon.com/6-15P-C13-Pow...2?s=electronics&ie=UTF8&qid=1313504232&sr=1-2

DO NOT use these cords unless you PSU is designed to accept a 240v input AND the voltage switch (if it's not autoranging) is set for 240v. You can set your shit on fire if you're not paying attention.
 
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ah ok, that explains it. I have never seen the low amperage plugs before, just the 50 amp stuff.
 
normal new drier plugs have four prongs (old ones had three) the two hot, one neutral and one earth ground. If you were to tie the two hot leads to the hot and neutral leads on the normal cord what would you hook to the normal earth ground pin?
 
nwrtarget said:
normal new drier plugs have four prongs (old ones had three) the two hot, one neutral and one earth ground. If you were to tie the two hot leads to the hot and neutral leads on the normal cord what would you hook to the normal earth ground pin?
Click to expand...

You wouldn't use a drier plug, that's designed for an appliance that uses 240v (hot-hot) for the heating element and 120v (hot-neutral) for the motor, timer, and lights. The ground is purely for safety and is connected directly to the appliance case. In the older 3 prong drier plugs, the Neutral was bonded to the appliance case, but the NEC decided that wasn't safe enough and required a separate ground conductor all the way back to the panel.

For a PC, you would use a socket that is designed for only 240v (i.e has no neutral) and use the cords I linked above.
 
nwrtarget said:
In the US the 220 V home outlets all have two hots leads and the difference between them gives you 220 volts. I am not sure how you would wire that up to a PC because it only has one hot lead connection. Like said above you will save a little if you can pull it off.

amdgamer You have a space heater in your computer room? Who needs a space heater in their computer room? Someone who needs more folding rigs.
Click to expand...

The dimwit who designed this house didn't put any heating or cooling on the second floor which is my computer room. As a result it needs a space heater in the winter and a window unit in the summer. On a hot upper 90's day, temps in the computer room can easily hit 135+ degrees. As a result, both folding rigs are down in the guest bedroom which is cooled and heated with the rest of the house. I would like to add more folding rigs, but just don't see myself having the funds for the time being.

My computer room also serves as my entertainment room as it holds my gaming PC, DVD and HD-DVD players, sound system, and of course my Xbox 360.
 
I was told many years ago that a 220 circuit was more efficient than a 120 because of load imballance at the tranformer at the pole. Not sure if anyone has any info on this. I tried to google it to back up the theory but found so many stupid answers that I finally quit reading.

In any case it makes sense to me that if you load the transformer at the pole only on one side that it will actually be less efficient. Therefore actually using slightly more current to drive the household.

In any case I use a clamp on multimeter to measure current throughout my electrical service box and try and balance all the loads as much as possible. Easy to do if the box was wired correctly to begin with. Or if your like me, you take out the original service box and put in a new one and wire it with long leads than can be moved around some to balance things.

Just my .02

I have thought of going 220 in the computer room but never done it.
 
I've thought of going partially 240 in the server room. Basically, one or two circuits that are 240 and the rest 120. From my understanding a 240v 15a circuit would have double the capacity (3600w) of a 120v 15a circuit (1800w).

The problem is finding a UPS that will take 240. Would probably need to either buy from the UK or do a specialty order.
 
We have a 240 plug here in the office, well at least I think it is.

It has orange plugs and is set off on it's own.

It goes to the sever rack here.
 
Red Squirrel said:
The problem is finding a UPS that will take 240. Would probably need to either buy from the UK or do a specialty order.
Click to expand...

Looks like most of the larger online retailers sell 240V UPSes. Best bet would probably be to find the model you want, then find it on Amazon for some free Prime or Super Saver shipping.
 
Kendrak said:
We have a 240 plug here in the office, well at least I think it is.

It has orange plugs and is set off on it's own.

It goes to the sever rack here.
Click to expand...

does it have one or two of the slots turned sideways? If not, then it's a 110v. The color probably means it's on a backup generator.
 
Parja said:
Looks like most of the larger online retailers sell 240V UPSes. Best bet would probably be to find the model you want, then find it on Amazon for some free Prime or Super Saver shipping.
Click to expand...

Hmm yeah did not figure it was that common but found some too:

http://www.N C I X.com/products/?sku=42214&vpn=SUA3000RMT2U&manufacture=AMERICAN%20POWER%20CONVERSION

And... ME WANT!!!
http://www.N C I X.com/products/?sku=63207&vpn=SUA5000R5TXFMR&manufacture=AMERICAN%20POWER%20CONVERSION


208 is usually 3 phase, but should not matter, as it's only using one phase anyway.
 
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Red Squirrel said:
Hmm yeah did not figure it was that common but found some too:

http://www.N C I X.com/products/?sku=42214&vpn=SUA3000RMT2U&manufacture=AMERICAN%20POWER%20CONVERSION

And... ME WANT!!!
http://www.N C I X.com/products/?sku=63207&vpn=SUA5000R5TXFMR&manufacture=AMERICAN%20POWER%20CONVERSION


208 is usually 3 phase, but should not matter, as it's only using one phase anyway.
Click to expand...

A single phase of a 3phase 208v supply is 120v. So, it's not going to do you much good on the PC end.
 
So, why is this supposed to be better? I can't find anything that says that it is more efficient in any way. Maybe I'm just missing something though. Is it that you can get more amps on the 230? Isn't the switch just so that manufacturers don't have to make different models for different parts of the world?
 
Doozer said:
So, why is this supposed to be better? I can't find anything that says that it is more efficient in any way. Maybe I'm just missing something though. Is it that you can get more amps on the 230? Isn't the switch just so that manufacturers don't have to make different models for different parts of the world?
Click to expand...

a 500 watt power supply will use about 4a from a 120v source, Where it would only draw 2a from a 240v source. More amperage means more heat due to the internal resistances inside the PSU. More heat means power is being lost and thus the psu is running with less efficiency.
 
Ok, gotcha. I was thinking more efficient in terms of the power bill. I was indeed missing something. :)
From what I found the difference in the bill would be negligible unless you were running something the size of a data center. I think that some of us may just be. :)
 
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Doozer said:
Ok, gotcha. I was thinking more efficient in terms of the power bill. I was indeed missing something. :)
Click to expand...

It does mean that. If you're wasting less power through heat, then more of the power you're pulling in goes to powering to the PC instead out the back as heat. So you don't have to pull as much from the mains.

In other words, that 500w PSU will do whatever it needs to do to make sure your PC is getting 500w. That means if at 120v it's losing 20% efficiency due to resistance and inductive losses, then you're going to have to pull 625w from the wall. But at a 240v, fewer amps are needed to provide 500w, so you lose less power from resistive heat dissipation and your efficiency goes up to say 82%, then you're only pulling 610w from the wall.
 
Here is something to think about that I found over at ExtremeTech. I am by no means an expert on this subject and I don't know if this guy is talking out of his ass or not. I just don't want to hear that someone has burned down their house or fried some expensive hardware. :eek:

I hate to burst your bubble...but if you are planning to just 'switch' the power switch from 115V to 230V on your PC you are out of luck. The 220/240V power in your house, or in the USA for that matter, is the same as the 230V power in the rest of the world. THe 115V/230V switch allows the same equipment to be used world wide.

Here, the 220/240V power is "phase-to-phase", two 'hot' legs and no neutral (grounded) conductor plus a ground (grounding) conductor.

The 'Europoean' 230V power is "phase-to-neutral" just like our 120V power. One 'hot' leg, one neutral (grounded) conductor plus a ground (grounding) conductor.

In regards to some of the other comments...the advantage of 240V power over 120V power is that it pulls 1/2 as many amps, thus allowing for lower amerage circuits and smaller wire. You power bill is based upon kW...and kW is kW no matter what the voltage is.

1200W/120V=10Amps

1200W/240V=5Amps

Hope this helps,

SMOEGON
Click to expand...
 
Doozer said:
Here is something to think about that I found over at ExtremeTech. I am by no means an expert on this subject and I don't know if this guy is talking out of his ass or not. I just don't want to hear that someone has burned down their house or fried some expensive hardware. :eek:
Click to expand...

He's mostly talking out of his ass. Phase to phase or phase to neutral makes not one bit of difference.
 
ah, then have at it guys. :)

Just be careful that you don't accidentally plug something else into one of those outlets. I've seen some pretty expensive electronics go up in smoke.
 
Doozer said:
ah, then have at it guys. :)

Just be careful that you don't accidentally plug something else into one of those outlets. I've seen some pretty expensive electronics go up in smoke.
Click to expand...

Well, I did say before that you have to make sure your equipment is set to handle 240v operation, or you can catch your stuff on fire.
 
This really makes one think about how much we could increase efficiency across the board at a time when electricity is becoming a scarce commodity in some regions of the US. A good chunk of the world is now running a 220volt system and we are still stuck at 110.

This is something I will have to seriously think about as i've been told numerous times that I could see some serious efficiency gains if I ran a 240volt window unit in the computer room instead of the 120volt one.
 
amdgamer said:
This really makes one think about how much we could increase efficiency across the board at a time when electricity is becoming a scarce commodity in some regions of the US. A good chunk of the world is now running a 220volt system and we are still stuck at 110.

This is something I will have to seriously think about as i've been told numerous times that I could see some serious efficiency gains if I ran a 240volt window unit in the computer room instead of the 120volt one.
Click to expand...

Why stop there, upgrade to 3-phase. Use even smaller wire on the motors.
A much bigger problem is Japan, they operate on both 50hz and 60hz systems.
 
As a licenesed electrician I would just like to chime in. First most of these PSUs have a switch to run on between 110 to 120VAC and 220 to 240 VAC. The variable here is that generally most PSU units are designed to run at 60 hz when switched to 110 and 50 hz when switched to 220. There is a small chance that the frequency of the sin wave does not matter due to the fact that the current is all being turned into DC power.

Almost any US household has the capability from the pannel to run a 220V circuit. You just run 2 hots off the pannel and a ground, the neutral is not needed generally but some stoves need it, so it depends on application. Stove and Dryer circuits are too high of an amperage for a computer, if there was a short chances are that the breaker wouldn't trip. On top of that I'm pretty sure that no PSU manufacturer would supply you with a cord with a dryer plug on the end. So you would either need to see if you would get one with a twistlock on the end or make a cord with a twistlock on the end. Then you would need to supply a breaker and receptacle to match. All of these items should be avalible in a local hardware store or on the internet. The smallest easily avalible 220/240V breaker you will find is 20A, but a 15A breaker would suit your needs better if you could find one.
 
hpglow said:
As a licenesed electrician I would just like to chime in. First most of these PSUs have a switch to run on between 110 to 120VAC and 220 to 240 VAC. The variable here is that generally most PSU units are designed to run at 60 hz when switched to 110 and 50 hz when switched to 220. There is a small chance that the frequency of the sin wave does not matter due to the fact that the current is all being turned into DC power.
Click to expand...
Most PSUs (and all quality PSUs) nowadays have active PFC, so they do not have switches. The PFC circuitry will deal with converting the input voltage to whatever the primary side needs.

There is a 100% chance that the frequency doesn't matter, since the PSUs are designed to work with 60Hz and 50Hz input signals to begin with. Which voltage corresponds to which frequency makes no difference.
 
Thanks for clearing up my confusion on the matter guys. Who is going to try this first? ;)
 
This is a great thread and I agree with what has been said. Get the 240V rolling guys! There are many reasons why power lines use really high voltage. One of them being that voltage drop is linear to the resistance in the line, which is based on wire size, distance, material, and temperature. So say there is X distance with Y gauge wire, and your source is 120V and you get 119V out and with a 240 volt source on the same line you would get 239V so say we push to 1 billion volts that line would give 999,999,999 volts. Now we also get into the fact that the higer the voltage the less current which also plays into the equation since more current means more heat and more heat causes more resistance until the wire fails. So the benefits are two fold.

Who will be the first [H]ard memeber to go suputer conductive? haha.
 
It will be a while, but when we upgrade the electric service to the house I'm tempted to have them run a 240 line to where the rack will be.

But if I'm running it to a UPS, does it really matter?
 
If the UPS takes 240V it will still matter. The UPS will become more efficient, and there are UPS's that output 240V. Any voltage increases will bring efficiency increases (assuming the load doesnt change).
 
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