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I have two 5 card rigs.

Each one has 2 PSUs.  The PSUs say they are 110-240V.  At 110V they use 12 amps, at 220V they use 6 amps.


My whole house is mostly wired with 15 amp breakers.


I have a friend who is an electrician and will come run me a couple 20 amp 220V breakers/outlets.


Only thing is he isn't sure if you can plug the PSUs up to 220 once they have been plugged into 110.


None of the PSUs have 110/220 switches on them.  They are supposed to automatically sense which V it is hooked up to.  But I know some PSUs (not computer ones) want whatever they are hooked up to originally.


So since I have already been running my PSUs on 110 can I switch them over to 220 or will they not like that now?



Much thanks!

If it does not have a voltage selection switch, then it is a newer design with active PFC. A feature of an active PFC system is that the input voltage doesn't matter as long as it's within its design range.

You could literally plug it into an adjustable transformer and spin the knob up and down from 90-240vac and the psu wouldn't care.

If it's an older design with the red voltage switch in the back, you will just need to flip it to 240v and you will be good to go.

I worry about an electrician that can't simply look at a PSU Label, as all modern PSUs that I know of state that they are designed for 120 and 240 input. That aside, photon said it all.

He isn't looking at anything.



He works as an electrician at Tropicana.  He said that some of the power supplies they use up there will take 110 or 220 also but that once you hook it up it always wants whatever it was hooked up to first.

He wasn't sure if the computer PSUs were the same.

lol.....
it is STill the same number of watts, it is not magic you do not get anything for free......

Yes they are switched mode PSU they work from about 95-350V,  they really do not care if they have been on 110 before.

Only point is to make sure there are no dust bunnies and they have GOOD ventilation round the components because at 240 the break-over distances will be reduced  if it is damp.

yeah, thats why active PFC tends to survive a voltage surge more often than not, cuz they are extremely flexible ... and past the 300v range is when ur surge suppressor starts to clamp.

So he thinks they'd put a sensor and a circuit to remember that and burn it to memory forever, rather than just a sensor.

Think twice about allowing him to rewire your home.

for active PFC PSUs you don't need to switch the voltage, but you should check the manual first.
for a passive PFC one there may be a voltage switch on the PSU

I think OP is wanting it to draw lower amps.

Computer PSUs certainly do not behave this way. I doubt any device would...

Well sort of. They can take 110 or 220, but you can switch anytime you would like.

It's automatic and your friend is an idiot and shouldn't be an electrician.

Yes, we european residents (and rest of the 220-240 V world) is plagued with PSU fires. lol

Mmmm not quite. Most PSUs will run More efficient (http://en.wikipedia.org/wiki/80_Plus#Efficiency_level_certifications) on a 220V line.

It's still the same wattage being drawn by the cards, that much is true. But, at the same wattage and higher voltage, the amps go down, which means less heat (heat = wasted energy). This lowers are draw from the wall, and can lower your bill. Only by 1-2%, but still...

EDIT: fixed a crucial mistake, and fixed a typo.

^This.  He's correct.

 ::)

I just can't believe there's electricians that are so incompetent. I'm sticking to diy.

+472

This.  Or ask him to lay off the weed for a few days before coming round.

If the PSU doesnt have a switch and the label says 110-240v then it will auto switch. I would be more worried about your electrician friend replacing your breakers with 20A versions without checking whether the wire gauge was thick enough on that circuit to support the increased current you plan on drawing. If it's too small, you'd have to replace the wire with thicker gauge before using 20A breakers. Unless you really are itching for a house fire, that is.

I'm not having a 20 amp breaker put in.  I'm having 2 220 V breakers/outlets put in.  If it was just switching a breaker I would do it myself.

If the idiot thinks psus have drm, you're begging for a house fire if you don't hire someone else. This is his profession. It's like a doctor saying something retarded.

I was not aware of this. The lower heat would also mean less cooling required and longer part life though, wouldn't it? If so, I think that benefit alone would be worth it. Unless it's only a small amount of heat that is reduced.

Ps if he's truly a good friend then it's your obligation to get his license taken away before he says, this drm breaker can't be turned back on and kills himself. If he's not a good friend, then please let natural selection kill him.

Pps yes 220v upgrade really is worth it but GET SOMEONE ELSE!

I think the only parts getting reduced amperage would be the wire from the wall and the primary coil of the transformer, not gonna make a huge difference as those ain't things that are likely to go bad, the solid state components give out wayyyy before the transformers!

Ppps I hope you realize you must use different plugs and replace the cable. Don't let him reuse the outlet!

@bitpop:  I don't understand why you think the electrician is an idiot.  Electrician <> Electrical Engineer.  It would not surprise me if there existed some industrial machinery that *did* remember its original voltage settings.  And why should the Electrician know how CPU power supplies are designed?  It sounds to me like he told his friend (the OP) "I don't want to be blamed if the higher voltage burns out your computers."

@snootch:  Nothing in this thread suggests the electrician is incompetent.  He should know what gauge to use for a 20A circuit.

@OP:  I will give your electrician the benefit of the doubt and assume he is doing everything by the book.  Most jurisdictions require you to pull a permit, even for DIY work of this nature.  Your electrician friend shouldn't mind as long as you pay the permit fees.  You get the benefit of having the work inspected, and the permit fee sometimes let the materials be purchased free of sales tax.  In the worst cases, without a permit, your insurance might not pay off, or you might not be able to sell your home in the future, or an overzealous code-enforcement department might even try to condemn your property.

There may be restrictions on where a 240V outlet can be placed in a residence.  [The kids' bedroom might not be a good idea.]  And unlike 120V circuits, which can feed multiple outlets, a 240V circuit may be limited to a single outlet.  [A 20A circuit will be overkill for one computer with a 5A power supply input.]

You do understand your savings won't be half?  Power = Voltage * Current.  So twice the voltage and half the current results in the same (approximate) power consumption.

As others have said, some of your savings will be in lower losses from your electrical panel to the back of the computer.  If you really want to be as energy efficient as possible, consider asking the electrician to use the next smaller gauge (larger diameter) compared to what code requires.  The wire will be more expensive, but you might make that back over a few years.  You could get some of this benefit by sticking with 120V circuits, but rewiring from 14 gauge to 12 gauge, for example.

The label of an HP power supply I am looking at says the input is 10A at 100-127V, and 4A at 200-240V.  That suggests the power supply may be more efficient at 240V.  Your power supply labels don't suggest a big difference in efficiency, but the manufacturer's Web Site may have better specs that would tell you if there is better efficiency at the higher voltage.

Finally, do you have a 240V electric dryer or electric range outlet in your home?  If you can find a cord, you could test before you rewire.  First, if you are concerned about burning out your computer, remove all of the expensive GPU cards and drives and test with the most bare-bones system you can.  I don't know if there is a 240V Kill-A-Watt meter in the US.  So, when you decide it works, turn everything in the house off, including the refrigerator.  Go out and see if the meter has stopped spinning.  Then turn on one computer, plug it in to 120V and fire up your miners.  Go out and watch the meter.  Time how long it takes to go around once (or a few times).  Then plug it in to 240V and fire up your miners.  Go out and watch your meter, again.  You probably can measure a 5% change in billed power consumption.

Yea I didnt feel like arguing with everybody here.  The guy is almost 60 years old (guessing but prob close) and has been a cert electrician for Tropicana for nearly 30 something years.  And he is the most senior electrician there.  Im sure if the Trop trusts him with millions and millions in equipment he can run a breaker.  Even though he knows more about computers than most people I know his age he still is almost 60 something years old so I dont think hes up on anything that has happened in the last 10 years computer wise.


But yea the only reason I did this was because I have 2 five card BAMT rigs.  I want to put them all in the same room because of the heat.  If I do this they keep tripping my breakers because all of my rooms except for the bathrooms/kitchen have 15 amp breakers.  I was gonna run two 110V 20A breakers but I decided it would be better to run two 20 A 220V breakers.

My PSUs say 110-240V @ 12-6 A respectivly.  I have 2 PSU per rig.  So on 110 its 24A and on 220 its 12A.  Per rig.



So Now I have two 220V 20A outlets to plug my rigs into.  I dont really care about code or anything like that.   Ill just remove it if I move.

Pics!

I've wondered about something like this. If you live in NA where 120v circuits are standard and get 240vs installed to power your rigs, how do you reconcile the different plug shape? Adapters seem perilous because they're usually sold for people traveling between EU/NA, rather than for continuous, high load use.

There are US standard plugs for 240v outlets

http://upload.wikimedia.org/wikipedia/commons/thumb/0/0d/NEMA_simplified_pins.svg/350px-NEMA_simplified_pins.svg.png

The look pretty flimsy. UK plugs are really robust and very safe, till you step on them, OUCH.

They work fine. UK plugs are pretty over-engineered (and yes, not much fun to stand on in the night). Though I would say that US plugs are a little under-engineered (hate having to straighten the pins to be able to use them).

Guess that makes the europlugs the happy medium. :)

GO Europa! :P

Pretty reasonable if you have the ground pin.

One thing with the US plugs is that they tend to stick out which is untidy and a problem with furniture. You can get plugs with side-exit cables but you're typically stuck with what came with the equipment and they have the issue with the standing-on (though rare enough to not be a real issue). I really don't know why we haven't managed to solve this issue already. It doesn't seem all that complex. Especially with modern manufacturing techniques.

You buy a replacement cable for your psu