# Running pc on 220v in the USA

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August 12, 2011 9:40:00 AM

I have a machine that I have running 24/7 with a fairly heavy load that I want to run on 220v. I have a plug located fairly close to where my pc is running, so I want to use it. My question is can a PS run on a pair of 110v lines, or does it require a single 220v line?

More about : running 220v usa

a b ) Power supply
August 12, 2011 9:49:11 AM

if the PSU support the range 90 - 240, I think you'll be fine. check in label PSU !
and if the PSU No support it, then you can use UPS or transformer Step Up 110 to 220v.
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August 12, 2011 9:56:53 AM

It's compatible with 240, however that still doesn't answer my question, of if it can run on a pair of 110v or if it needs a single 220v line.
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a b ) Power supply
August 12, 2011 11:13:32 AM

See label PSU, have not range 90-240 input voltahe you need UPS or converter VAC. I know in US 110V. Example PSU seasonic ran at range input voltage 90V- 240 VAC , you do not neet anything just fine and enjoy with your PSU ran at 110V , the psu will convert voltage by self.
Look like this :
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a c 289 ) Power supply
August 12, 2011 1:46:44 PM

The way US 220V is set up is different than the way european 220V is setup due to their being a hot, and another hot of the opposite polarity instead of a single hot and a neutral and i believe thats the question you are getting at. Since its AC power, all the unit cares about is the difference between the lines, not that one is +110 V and the other is -110 V all it senses is a 220 V difference between the two so it will still work just fine.
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August 12, 2011 3:31:49 PM

The answer is NO NO and NO.

You need to run a DEDICATED circuit to do what you are doing OR change the breaker AND the outlet that you want 220V on.

AC electricity is different that DC. 110+110 != 220, it is = 110, unless you happen to use a different phase or side of the plug, and if you do a "hey, let me jury rig for 220 from two outlets" you can possibly do 220V on the WHOLE circuit and BLOW UP everything on that circuit!

and you need a different plug for 220v, it is | -- instead of | l (one vert and one horizontal, instead of two vert)

So yes, you have to use the dedicated outlet that you have already. The only thing I do not recall is if the phase matters to the psu, us power is two phase (hot+hot) and european is single I think (hot+neutral)?
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August 12, 2011 3:48:27 PM

Seconding hiring a licensed and bonded electrician. You will want to follow the local electrical code and the manufacturer's guidelines.

That's even assuming that there's some good reason for the machine to be on 220v. I can't say I've ever heard any, I've seen a study based on DC, but that's a different principle at work.

If you're just having problems with the load on the machine, you want more watts out, not more volts input. Though I suppose some PSU's do uprate based on the input, it's not enough to matter compared to a better CPU.

If you want to save money on electrical costs, there's probably better ways.
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August 12, 2011 7:56:45 PM

hunter315 said:
The way US 220V is set up is different than the way european 220V is setup due to their being a hot, and another hot of the opposite polarity instead of a single hot and a neutral and i believe thats the question you are getting at. Since its AC power, all the unit cares about is the difference between the lines, not that one is +110 V and the other is -110 V all it senses is a 220 V difference between the two so it will still work just fine.

Ive asked on a couple forums and this is what I gathered as well.

ngoy said:

The answer is NO NO and NO.

You need to run a DEDICATED circuit to do what you are doing OR change the breaker AND the outlet that you want 220V on.

AC electricity is different that DC. 110+110 != 220, it is = 110, unless you happen to use a different phase or side of the plug, and if you do a "hey, let me jury rig for 220 from two outlets" you can possibly do 220V on the WHOLE circuit and BLOW UP everything on that circuit!

and you need a different plug for 220v, it is | -- instead of | l (one vert and one horizontal, instead of two vert)

So yes, you have to use the dedicated outlet that you have already. The only thing I do not recall is if the phase matters to the psu, us power is two phase (hot+hot) and european is single I think (hot+neutral)?

The plug that I have is a typical dryer plug. It has 2 110v lines, and a neutral.

MysticMiner said:
Seconding hiring a licensed and bonded electrician. You will want to follow the local electrical code and the manufacturer's guidelines.

That's even assuming that there's some good reason for the machine to be on 220v. I can't say I've ever heard any, I've seen a study based on DC, but that's a different principle at work.

If you're just having problems with the load on the machine, you want more watts out, not more volts input. Though I suppose some PSU's do uprate based on the input, it's not enough to matter compared to a better CPU.

If you want to save money on electrical costs, there's probably better ways.

Better efficiency, if only by a few percent. The circuit it's on has other stuff on it, and with it having 2 video cards in it crunching numbers, it does draw a decent amount of current. I'm not sure why everyone is thinking I need an electrician. It's no different than plugging in a (insert device) into an outlet, it's just a question of if the PSU can run off 2 phase vs Euro style single phase 220v.
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a b ) Power supply
August 12, 2011 8:22:16 PM

A PSU uses a transformer to step the voltage down (Sure you know already). It could care less if the input is two phased 110 or a single phase 220. What you need to verify is two things. (A) Is the one input side (Nuetral) tied to case ground on the inside of the PSU - IF so BIG arc and blown fuse. (B) input EMI filtering, again on the normally nuetral line, need to verify that the caps going from this to chassie Ground have a high enough voltage rating (normally only a couple of volts so manuf could have saved some money and used a lower rated Cap.

If OK on above two points, then go for it.

- But really not going to help much. Going 220 vs 110 will halve the current, this will reduce the IsqR losses between main breaker and back of computer. So in an extreme case you drop your current from 10 amps to 5 Amps. Loss would equate to about 2.5 Watts Max and a Edrop of maybe 0.5VAC (Using a HIGH R of 0.1 ohms from breaker to Computer. In reality loss will probably be less and 2.5W vs 1000 Watt is like only 1/4 of 1 %
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a b ) Power supply
August 12, 2011 8:43:30 PM

Although the phrase "2-phase" is common, it's not actually true. In Canada and the USA the common household supply system runs three wires into the home from the transformer. Two of them are from opposite ends of the transformer secondary coil, and the third is from a center-tap of that coil. That last line is GROUNDED at the transformer and again in your house, establishing the 0 Volts reference point. It is called the NEUTRAL wire - it is NOT the same as the true GROUND wire that runs inside your house wiring. Referenced to that Neutral, each of the other two lines is at 110 VAC from it and are called "HOT" lines or L1 and L2. They actually are out of phase from each other by 180 degrees, so the difference between these two Lines (L1 to L2) is 220 VAC.

In Europe the wall outlet provides 220 VAC between the two power connection points (blades), and I do not know whether either of them is connected to Ground to establish a 0-volt reference point for the Neutral line. Here in North America the common household outlets provide 110 VAC between the two power connections (blades). Most commonly the WIDER of the two blades is the Neutral line - some older homes have outlets with both slots the same size. The Hot (narrower) blade is supplied from only ONE of the two Hot supply lines (L1 or L2) at the breaker panel.

In North America to provide 220 VAC to a load device you need to install special wiring. Well, in fact the wire cable in the wall may not be different (depends on current rating and on whether you need to supply the Neutral line at the outlet), but the outlet fitting AND the breaker supplying the circuit must be different. The outlet fitting must be unique so that no "regular" device (that uses 110 VAC) can be plugged in by mistake. Then of course, the plug on the end of the cord from your appliance (the computer in this case) must be installed to match the wall outlet configuration. The blade configuration is specified in Electrical Codes and depends both on the voltage and the maximum current rating (the breaker rating) of the circuit. The wire cable for the circuit also must match the maximum current of the breaker so that the breaker does provide adequate protection from over-current conditions causing excess heat.

The breaker is a particular type, called a dual-pole breaker. It draws power from both the L1 and L2 buses on the Breaker Panel to feed out to the circuit. It acts to sense current in BOTH of these two Hot lines and to switch BOTH of them off simultaneously. This ensures that there can be no voltage from either of the Hot lines out in the circuit wiring if the breaker is off.

So, to answer OP: you CANNOT feed your computer 220 VAC by fiddling with two 110 VAC standard house circuits. You must have a dedicated new circuit installed from the breaker panel with the correct breaker, wiring, and outlet fixture. Then you must change the plug on the end of your computer's cord and change its power supply input voltage setting switch if it has one.

You should NOT plug into a dryer outlet. That outlet has a breaker and wiring suitable for 220 VAC AND 35 to 40 Amps, to match a dryer's load. If you plug into that a device (your computer) wired with lighter wires for up to 15 amps, it could fail and draw 30 amps, sufficient to burn out its internal wiring and cause a fire, even though the breaker will NOT trip because it is not overloaded. The breaker is there to protect against overcurrent conditions in ALL of a circuit, including the house wiring AND the consumer device you plug into it. So the breaker and the consumer device's wiring need to be matched.

I guess you'll have to assess whether saving a couple percent in power supply efficiency is worth the time and expense of installing a new dedicated outlet for the computer. If you save 2% on a unit pulling big power like 1000 W, you'll save 20 watts. If the machine runs 24/7, that can come to about half a Kilowatt-Hour per day, or 175 KWH per year. Even if your electricity costs 15¢ per KWH, that gets to about \$26 per year.
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August 12, 2011 9:27:32 PM

blackdragonx1186 said:

Better efficiency, if only by a few percent. The circuit it's on has other stuff on it, and with it having 2 video cards in it crunching numbers, it does draw a decent amount of current. I'm not sure why everyone is thinking I need an electrician. It's no different than plugging in a (insert device) into an outlet, it's just a question of if the PSU can run off 2 phase vs Euro style single phase 220v.

The few percent is probably not worth it, and I saw a picture of the outlet you posted elsewhere, it did not look like it was in good condition. I would get an electrician.

And that's even assuming you can find a compatible cord for your PSU. If you have to rig something up yourself...really do stick with an electrician.

Or at least have a fire extinguisher ready.

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September 25, 2012 2:28:26 AM

I replyed but a lawer friend of mine suggested I remove it sorry I couldnt do more
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