4 ms·

a 220 volt 20 amp circuit should be good for over 3500 watts constant load in North America. Why is it requiring two circuits?

hashhar 2y ago
IIRC USA is 110V, not 220V?
- WoahNoun 2y ago
  Most US homes have at least one 220v split phase line for major appliances like stoves or AC.
  - teraflop 2y ago
    Yes, but most homes don't have extra 220v outlets except for the ones provided for the specific appliances that need them. So if you want to plug in a device like this "tinybox" at home, it's going to be a lot easier to find two separate 110v outlets on different circuits than to have a new 220v circuit added, or to unplug your stove every time you want to use it.
    - michaelt 2y ago
      Who needs a stove? My 3200W GPU box puts out more than enough heat to roast a chicken.
    - philistine 2y ago
      I don't know what adversarial relationship you have with electricians, but adding more 220v outlets is absolutely feasible. Usually takes an electrician a day of work.
- bitexploder 2y ago
  I have a lot of 220V circuits. One is like 80A and powers a whole building. Also, almost all power comes into a home as 220V single phase from the local power distribution. Water heater, heat pumps, stove, dryer, hot tub, etc are all 220.
- IWeldMelons 2y ago
  220V is American version of what is known as 380V/400V elsewhere.
  - ianburrell 2y ago
    US three-phase power is mostly 208V, 240V, and 480V. The 208V is what normal residential 120/240V split-phase was made from. 240V is high-leg delta three phase and I think was old alternative to split-phase. 480V is used for light industrial that needs more power. There is nothing in US power system that is 220V.
    - IWeldMelons 2y ago
      Ackshually, you need to tell that the GP of the thread, they began using "220v".
- cptskippy 2y ago
  Most homes have a 240V supply with a neutral wire (V1, V2, N). This allows for split phase 120V power (V1+N, V2+N). You can also get 240V (V1+V2). It's common for EVs, clothes dryers, ovens, and hot water heaters to use 240V while most other appliances are 120V.
luma 2y ago
Because most households in the US might have maybe 3 breakers setup this way, all of which are likely running critical infrastructure already. Most folks aren’t going to unplug their water heater to turn on their AI.
- bob1029 2y ago
  Swapping an electric dryer around is maybe more practical. It also gives you an obvious place to dump the waste heat. If I was serious about this I'd have an electrician and HVAC installer on the way first. A mini split in the computer room with a dedicated 50A/220v circuit.
- mmmlinux 2y ago
  I assume the people dropping 15$k on one of these to have in their house are comfortable with paying an electrician to wire it in if necessary.
michaelt 2y ago
Most likely what they actually mean is: This server has two IEC C20 connectors, rated for ~16 amps, each feeding a PSU rated for 1600W (i.e. 16A @ 100v) If you're plugging in to 110v you shouldn't plug them both into the same outlet, as a 20A circuit can't supply 32A. As each PSU is rated for 1600W you'll have to plug both in to get 3200W even if you're running on 220v - although they'd only draw ~7.2A each in that case. US Residential 220v dryer outlets are usually wired one-circuit-to-one-outlet, and multi-way adaptors are discouraged. So although plugging two 7.2A loads into a single 20A feed would work from a current perspective (and indeed it's common in Europe), I don't know how easy it is to do legally. If you're in a data centre with a 3-phase 220v power you probably know what you're doing. Your UPS guy will probably thank you if you split your load over two phases instead of putting the whole load onto one phase.
- bombela 2y ago
  You can feed a US outlet the split phase 240V and get two 120V@20A each. It used to be done in kitchens in the US, back when appliances were power hungry. I have done so in my workshop for the same reason. Houses are wired in split phase 240V, with the neutral in the middle. That is, you have two opposite 120V phases, around the same neutral. This is a clever way to double the power, while adding a single wire. In the US the standard outlet receptacle has two outlets. Bring the same neutral to the two outlets, and assign one phase per outlet (outlets have metals tabs you can break off, you don't need any extra wiring). At the panel, you have a dual breaker. One breaker per phase, with a physical linkage forcing them to trip and arm together at once. As a benefit; but very unsafe; you can make up a Y that plugs into the two 120V outlets, and gives you a single 240V receptacle. This is unsafe because if you plug only one of the 120V plug, the other one has now 120V on its exposed phase prong! On the other hand, I have both 240V@20A and 2×120V@20A anywhere in the shop ;)
  - oasisbob 2y ago
    GFCI requirements will interfere with the legality of many modern-day multi-wire branch circuit plans, yeah?
amluto 2y ago
There are few or no 220 volt circuits in North America. Your choices in that range are 208V or 240V. But yes, a power supply can draw around 240V times 20A = 4800VA, which is nearly 4800W if the power factor is close to 1. An office in an office building is more likely to have 208V.

hashhar 2y ago

IIRC USA is 110V, not 220V?

WoahNoun 2y ago
Most US homes have at least one 220v split phase line for major appliances like stoves or AC.
- teraflop 2y ago
  Yes, but most homes don't have extra 220v outlets except for the ones provided for the specific appliances that need them. So if you want to plug in a device like this "tinybox" at home, it's going to be a lot easier to find two separate 110v outlets on different circuits than to have a new 220v circuit added, or to unplug your stove every time you want to use it.
  - michaelt 2y ago
    Who needs a stove? My 3200W GPU box puts out more than enough heat to roast a chicken.
  - philistine 2y ago
    I don't know what adversarial relationship you have with electricians, but adding more 220v outlets is absolutely feasible. Usually takes an electrician a day of work.
bitexploder 2y ago
I have a lot of 220V circuits. One is like 80A and powers a whole building. Also, almost all power comes into a home as 220V single phase from the local power distribution. Water heater, heat pumps, stove, dryer, hot tub, etc are all 220.
IWeldMelons 2y ago
220V is American version of what is known as 380V/400V elsewhere.
- ianburrell 2y ago
  US three-phase power is mostly 208V, 240V, and 480V. The 208V is what normal residential 120/240V split-phase was made from. 240V is high-leg delta three phase and I think was old alternative to split-phase. 480V is used for light industrial that needs more power. There is nothing in US power system that is 220V.
  - IWeldMelons 2y ago
    Ackshually, you need to tell that the GP of the thread, they began using "220v".
cptskippy 2y ago
Most homes have a 240V supply with a neutral wire (V1, V2, N). This allows for split phase 120V power (V1+N, V2+N). You can also get 240V (V1+V2). It's common for EVs, clothes dryers, ovens, and hot water heaters to use 240V while most other appliances are 120V.

luma 2y ago

Because most households in the US might have maybe 3 breakers setup this way, all of which are likely running critical infrastructure already. Most folks aren’t going to unplug their water heater to turn on their AI.

bob1029 2y ago
Swapping an electric dryer around is maybe more practical. It also gives you an obvious place to dump the waste heat. If I was serious about this I'd have an electrician and HVAC installer on the way first. A mini split in the computer room with a dedicated 50A/220v circuit.
mmmlinux 2y ago
I assume the people dropping 15$k on one of these to have in their house are comfortable with paying an electrician to wire it in if necessary.

michaelt 2y ago

Most likely what they actually mean is: This server has two IEC C20 connectors, rated for ~16 amps, each feeding a PSU rated for 1600W (i.e. 16A @ 100v) If you're plugging in to 110v you shouldn't plug them both into the same outlet, as a 20A circuit can't supply 32A. As each PSU is rated for 1600W you'll have to plug both in to get 3200W even if you're running on 220v - although they'd only draw ~7.2A each in that case. US Residential 220v dryer outlets are usually wired one-circuit-to-one-outlet, and multi-way adaptors are discouraged. So although plugging two 7.2A loads into a single 20A feed would work from a current perspective (and indeed it's common in Europe), I don't know how easy it is to do legally. If you're in a data centre with a 3-phase 220v power you probably know what you're doing. Your UPS guy will probably thank you if you split your load over two phases instead of putting the whole load onto one phase.

bombela 2y ago
You can feed a US outlet the split phase 240V and get two 120V@20A each. It used to be done in kitchens in the US, back when appliances were power hungry. I have done so in my workshop for the same reason. Houses are wired in split phase 240V, with the neutral in the middle. That is, you have two opposite 120V phases, around the same neutral. This is a clever way to double the power, while adding a single wire. In the US the standard outlet receptacle has two outlets. Bring the same neutral to the two outlets, and assign one phase per outlet (outlets have metals tabs you can break off, you don't need any extra wiring). At the panel, you have a dual breaker. One breaker per phase, with a physical linkage forcing them to trip and arm together at once. As a benefit; but very unsafe; you can make up a Y that plugs into the two 120V outlets, and gives you a single 240V receptacle. This is unsafe because if you plug only one of the 120V plug, the other one has now 120V on its exposed phase prong! On the other hand, I have both 240V@20A and 2×120V@20A anywhere in the shop ;)
- oasisbob 2y ago
  GFCI requirements will interfere with the legality of many modern-day multi-wire branch circuit plans, yeah?

amluto 2y ago

There are few or no 220 volt circuits in North America. Your choices in that range are 208V or 240V. But yes, a power supply can draw around 240V times 20A = 4800VA, which is nearly 4800W if the power factor is close to 1. An office in an office building is more likely to have 208V.