standard 120v PSU into 240v?

sutheksuthek Member Posts: 271 ✭✭
I have a Corsair HX1000i and it's currently plugged into a 120v circuit.

However, I see the sticker on the power supply states "110 - 240v".

What confuses me though is that older power supplies had a little switch on the back that you'd flick to go from 120v to 240v.

How do I wire this into 240v without that switch? And what's the wiring diagram? Both main legs are 120v? And then the 3rd prong is neutral?
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Comments

  • RedsquirrelRedsquirrel Member Posts: 20
    Some PSUs can handle the full range without a switch. If you convert a circuit in your house or run a new one that is 240v then you would use both hots from the panel as power between two hots is 240 while any hot to neutral is 120. You would not use a neutral, the ground would still be ground.

    This would essentially double your wattage capacity for that outlet as a load that would normally use 10 amps might only use 5 now. (wattage stays the same of course). Just be careful to note that it's 240 and use proper plug type so you can't accidentally put a 120v load into it. You'll also need a UPS that can do 240, which may be hard to find.

    I'm new to mining myself, but I'm probably just going to stick to 120v for simplicity and just run a bunch of 14/3 BX to do a couple split 120v 15a plugs to my rack.
  • wirelessnet2wirelessnet2 Member Posts: 380 ✭✭✭
    @Redsquirrel so you are saying that you would just wire a 120/240 volt power supply as hot/hot/ground instead of hot/neutral/ground?
  • RedsquirrelRedsquirrel Member Posts: 20
    That's correct. Has to be two hots that are separate though obviously. In your electrical panel each breaker is staggered so you would put a double pole breaker which takes up two spaces, so the two hots on that breaker will be 240v. Though you need to check this when you do the install as panels may vary. Basically you can think of the incoming hydro feed as being 240v, but at the transformer there is a centre tap, that is the neutral. So between the two legs of the transformer you get 240v but between any leg and neutral you get 120v. For a dryer or stove you will often see a big plug that has 4 prongs instead of 3, the way this works is that the two side ones are 240, then one of them is neutral and the other is ground. But for a computer you don't need the neutral at all if you go 240v.

    Though if you are not familiar with electrical probably best to get an electrician to help.
  • noobminer001noobminer001 Member Posts: 7
    edited January 10
    Hello,

    I was thinking about this more and wanted to test it. I was under the impression that 110-240VAC labeled on electrical equipment, the 240VAC was for European/Asia standard where its 240VAC Line to Neutral. I wasn't sure how the equipment would handle two 110 hot lines if the equipment is looking for a neutral reference. I can understand if its labelled 240VAC for NA markets only, but I am pretty sure most of the equipment labelled 110-240VAC is intended for NA and EU/AS markets. Have you ever tested this? I am surprised if the PSU doesn't need a neutral reference if you feed it two hot lines (given that they are designed for European/Asia standard of 240VAC line to neutral). How would it complete the circuit? The neutral acts as floating ground or a bonded ground if its connected to Earth ground. Please don't take this as saying you're wrong, I actually want to test this but I don't have an old PSU and haven't got around to buying one but if someone has already tested this, I would like to know.
  • wirelessnet2wirelessnet2 Member Posts: 380 ✭✭✭
    edited January 11
    @noobminer001 That's why I was confused too! But I do know that the two 120v lines are not in phase, so the return current could return along the other hot wire. Some water heaters and whatnot only need two 120v hot lines and a ground. I think it may work...

    I found this
    https://diy.stackexchange.com/questions/33602/why-do-240v-circuits-not-require-neutral
  • sutheksuthek Member Posts: 271 ✭✭
    Anyone brave enough to test it with a power supply?
    best I can tell, the 240v on a PSU is expecting 240 on a single line plus a neutral.
  • wirelessnet2wirelessnet2 Member Posts: 380 ✭✭✭
    edited January 11
    I’ll call EVGA and ask them
    Edit: I called EVGA and asked the technical support if hot-hot-ground should work, and the rep said that as far as he knew that should be a valid and working configuration. I’ll put a 750 P2 to the test sometime (probably not too soon), and if it works I’ll report back.
  • sutheksuthek Member Posts: 271 ✭✭
    I don't trust customer service people. They don't know anything technical.
    I really think it needs the positive and a neutral.... but if someone has an old PSU to test that would be great.
  • sutheksuthek Member Posts: 271 ✭✭
    it might not though.
  • Ericjh801Ericjh801 Member Posts: 17
    I'm currently running EVGA power supplies (and a few others) on 240v in the US. I just had an electrician run 240v lines to a few different outlets (each on their own circuit) and use a power strip made for 240v. I can provide models of the power strips if anyone is curious. They seem to run really well, no issues thus far, just plug in and go.
  • sutheksuthek Member Posts: 271 ✭✭
    can you confirm the wiring?
    was it two phase? 120v x 2?

    Or did they somehow give you a single line at 240v?
  • Ericjh801Ericjh801 Member Posts: 17
    The outlet itself has two hots (120v) and 1 ground. It's a residence also if that helps (single phase power, not 3 phase). The breaker has 2 hots coming off of it (30 amp). So 120v x 2 on the breaker to the outlet, and then ground wire. No neutral. (Was wired by a master electrician who upgraded my power to support mining, along with the power company upgrading the main line to my house).

    It measure 120v from either hot to ground, and then 240v from hot to hot when I metered it.
  • sutheksuthek Member Posts: 271 ✭✭
    Ericjh801 said:

    The outlet itself has two hots (120v) and 1 ground. It's a residence also if that helps (single phase power, not 3 phase). The breaker has 2 hots coming off of it (30 amp). So 120v x 2 on the breaker to the outlet, and then ground wire. No neutral. (Was wired by a master electrician who upgraded my power to support mining, along with the power company upgrading the main line to my house).

    It measure 120v from either hot to ground, and then 240v from hot to hot when I metered it.

    Which power strip did you buy? Does it then take the 240 and distribute it as multiple 120v's?
  • wirelessnet2wirelessnet2 Member Posts: 380 ✭✭✭
    @suthek I just did it too. I got a bunch of AP7841 PDUs and connected them to 30A 240V circuits. It distributes 240 volta
  • sutheksuthek Member Posts: 271 ✭✭

    @suthek I just did it too. I got a bunch of AP7841 PDUs and connected them to 30A 240V circuits. It distributes 240 volta

    So you have USA two phase 240v (120v+120v+Ground) going into power supplies?
    Frig I need to buy a $50 power supply and just giver and see if it pops.
  • wirelessnet2wirelessnet2 Member Posts: 380 ✭✭✭
    @suthek yup. Two 120v hot lines offset 180 degrees from each other
  • Ericjh801Ericjh801 Member Posts: 17
    Exactly what wirelessnet says. The PDU he listed would work fine. I happen to have a few APC 240V PDU's around so I wouldn't have to buy anything else for it. All the PDU's are 240v input and 240v output and the power supplies don't care as long as it's 120 or 240. The PDU's only care that you stay under the 24 AMP max output. (You can run approx. 5760 watts constant on them)
  • sutheksuthek Member Posts: 271 ✭✭
    do I need a PDU though? Or can I just plug in? (assuming I change the outlet?)
    Like does the PDU change anything? or is it just a fancy powerbar?
    Ericjh801 said:

    Exactly what wirelessnet says. The PDU he listed would work fine. I happen to have a few APC 240V PDU's around so I wouldn't have to buy anything else for it. All the PDU's are 240v input and 240v output and the power supplies don't care as long as it's 120 or 240. The PDU's only care that you stay under the 24 AMP max output. (You can run approx. 5760 watts constant on them)

  • sutheksuthek Member Posts: 271 ✭✭
    but do I need one? or can I skip it?
    suthek said:

    do I need a PDU though? Or can I just plug in? (assuming I change the outlet?)
    Like does the PDU change anything? or is it just a fancy powerbar?

    Ericjh801 said:

    Exactly what wirelessnet says. The PDU he listed would work fine. I happen to have a few APC 240V PDU's around so I wouldn't have to buy anything else for it. All the PDU's are 240v input and 240v output and the power supplies don't care as long as it's 120 or 240. The PDU's only care that you stay under the 24 AMP max output. (You can run approx. 5760 watts constant on them)

  • Ericjh801Ericjh801 Member Posts: 17
    You don't "need" one, you could just have an outlet wired for 240V via a standard plug or a slightly different plug. I guess most people just use the PDU because it gives you 16 outlets from 1 using the L6-30P plug. It also saves you wiring a ton of outlets for 240v and just having a few for it dedicated to mining. (I have 4 L6-30R outlets with a PDU plugged into each one). I can run approximately 16 8 GPU rigs on these 4 outlets. (No I don't currently have 16.... i'm at 5 currently).
  • sutheksuthek Member Posts: 271 ✭✭
    I currently have the 6-30R which appears to be useless for this. (was previously a heater.)
    I removed it and put a standard wall outlet on it for testing. plugged in my PSU. worked like a charm with hot+hot+ground.

    I just ordered a L6-30P wall receptacle as I want this to be not accidentally used for 120v stuff.
    And I'm currently shopping for a cheap PDU.
    Some guy is selling an APC smx3000rmhv2u UPS PDU Power conditioner on craigslist for a few 100.
    Thinking I might just buy that? Thoughts?

    Seems liek L6-30P PDU's are a few 100 on ebay or whatever so might as well get a UPS used that can do the same.
  • wirelessnet2wirelessnet2 Member Posts: 380 ✭✭✭
    @suthek I just picked up some AP7941s on eBay for $127/ea. If you scout around you can really find some good deals.
  • sutheksuthek Member Posts: 271 ✭✭

    @suthek I just picked up some AP7941s on eBay for $127/ea. If you scout around you can really find some good deals.

    I saw those but they appear to be 208v.
    (for 3 phase applications in industrial situations)
  • wirelessnet2wirelessnet2 Member Posts: 380 ✭✭✭
    edited January 19
    @suthek the spec page says that they can output 230/240 volts as well. It should be fine since all the PDU is looking for is two phases. In the case of 240V it's two 120V phases offset by 180 degrees from each other, and for 208V its two 120V phases offset by 120 degrees from each other. The instantaneous product to create the actual power will still be there, and all the unit is looking for is between 200 and 240 volts. I hope I'm not wrong :D
  • Ericjh801Ericjh801 Member Posts: 17
    The UPS would work fine also depending on how many rigs you are running through it. They have a max wattage so just be mindful of that. I'd recommend the PDU for convenience. I'm using 2 30Amp PDU's and also have 2 20 AMP pdu's with adapters to L6-30P. Most of the APC adapters that say 208v, if they have the L6-30P will work fine and output 240 fine.
  • wirelessnet2wirelessnet2 Member Posts: 380 ✭✭✭
    @Ericjh801 are you sure? If thats true then I will buy some AP8941 PDUs. The spec sheet for those dont say 240v output, but the spec sheet for AP7941s do say 240v. Im worried that the AP8941 wont output 240v correctly... will it?
  • Ericjh801Ericjh801 Member Posts: 17
    I'm using an AP7841 if you want to look that up and compare to what you were looking at. It supports various output (200V , 208V , 230V , 240V) so find one that matches that I would assume. You should be able to get used/cheap older APC's on ebay.
  • wirelessnet2wirelessnet2 Member Posts: 380 ✭✭✭
    edited January 19
    @Ericjh801 yeah I bought a few 7841s off of eBay until I realized that I could get 7941s for cheaper AND they were switched. Switched ones are great because I can hard reset rigs remotely.
    And THEN I discovered 8941s for the same price... I was like oh great! Free upgrade! Until I looked at the spec sheet for 8941s and damnit there’s no 240v out
  • Ericjh801Ericjh801 Member Posts: 17
    Yup! I'm looking for some 7941's myself. Would be nice to hard reset ports when something hangs and i'm not around. Been an interesting experience setting up power/rigs/etc.
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