Electronics > Beginners
How to wire up a 240VAC receptacle
Spork Schivago:
--- Quote from: IanB on May 18, 2018, 02:12:40 am ---
--- Quote from: Spork Schivago on May 18, 2018, 01:46:26 am ---Then the servers themselves, as we verified once again, are designed for single phase 240VAC but learned they won't even power on if we attempt to feed them split-phase. This is probably a safety feature.
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A couple of puzzles with this are:
1. If you take the two line conductors from a split phase supply then that is, electronically, a single phase 240 V supply. The equipment being supplied cannot tell the difference between a 120-0-120 supply and a 240-0 supply unless it specifically measures the line-ground potential difference and acts on it. That seems unlikely as there would be no point.
2. A 240-0 single phase supply is nonstandard in the USA. So any equipment purchased in the USA for use in the USA market is unlikely to have this requirement--for the simple reason that nobody would have a suitable power supply for it. It makes no sense that the vendors would require customers to arrange a special installation with custom wiring, transformers and so forth just to use their equipment. Nobody would be prepared to stump up the cost.
The short answer is that equipment appears to come in two flavors: North America and "Worldwide", where "Worldwide" is everywhere except North America. It is logical that if servers, PSUs and PDUs are purchased with a North American specification for use within North America then they will be compatible with standard North American power distribution arrangements.
In North America the standard arrangements are 120-0 single phase, 120-0-120 split phase, or 208-0 single phase (derived from a three phase transformer). There could be three phase arrangements, but those are not under consideration here.
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Keep in mind, most of the equipment that is available for me is designed to run off of 3-phase. There aren't really any 120VAC options. And these power supplies are expensive, the server is very expensive. The CPUs are Xeon E5-v2699v4's, so maybe HPE techs are wrong? But they checked. They just didn't give me an answer. They came back and said no, the power supplies would not even power on with split phase. So, there is a good chance that they have circuitry to detect the voltage. Keep in mind, we're talking just the server, with options well over 100,0000$ for possible configurations. This isn't consumer grade equipment, it's Enterprise grade equipment. The mainframe is Enterprise grade, the switch is Enterprise Grade, the servers are Enterprise grade, etc. The GPU alone, they make a commercial model for consumers, but I cannot use that. I need a special version made for this server, even though the model numbers are the same. The price tag is not. And it's design is not the same either.
There's North American and Worldwide, but when you reach a certain level, it doesn't really matter anymore. I believe 3-phase is the same here as it is anywhere. And we were lucky that this PDU was available without needing 3-phase. Our PSUs do not say 120-240VAC. They're 220-240VAC. I guess there's a chance HPE techs where wrong? But I'm not going to try it and risk damaging the equipment because of the price we've invested this year alone, let alone all the previous years on equipment. The best I can do is give you my contact number for HPE and you can talk to them.
Heck, one of the options for my server is a DC power supply that supports 380VDC. I don't think that is common in households, but these servers are Enterprise grade and generally aren't ran in households. Maybe that's where we're running into trouble? Without knowing the exact equipment, people just speculate as to what we have. I can say each CPU cost over 4,000$ and we got them at rock-bottom price, where our VAR did not make any money at all on them. He did this because I was in the Marine Corps. I've recently switched doctors after this memory doc (who said he was in the military) went and told my civilian doctor (who ordered the memory tests) that I had PTSD. And that sucked, but they got me on new meds that seem to be helping, when I remember to take them.
If I was out of line, I apologize. I know you guys are just trying to help me get the best solution and safest solution. It's just a bit frustrating and I'm not really used to dealing with that. I got access to this site that I'm working through which helps you transition from the military world to the civilian world and run a business successfully.
A lot of this equipment isn't sitting around on a desk waiting to be sold. When I place the order with one of my VARs, they contact the various companies, and the company specially makes it for me. That was the case with the PDU, that was the case with the processors. I don't know about the PSUs though. We might be able to find a tear down for the PSU and see what happens?
It's fancy and supports other features as well, and maybe that's why split-phase won't work? They're HPE's Flex Slot Platinum Plus Hot Plug, 1400 watt, part number: 720620-B21
Spork Schivago:
--- Quote from: Monkeh on May 18, 2018, 02:17:45 am ---
--- Quote from: Spork Schivago on May 18, 2018, 02:10:19 am ---
--- Quote from: Monkeh on May 18, 2018, 01:52:23 am ---
--- Quote from: Spork Schivago on May 18, 2018, 01:46:26 am ---Then the servers themselves, as we verified once again, are designed for single phase 240VAC but learned they won't even power on if we attempt to feed them split-phase. This is probably a safety feature.
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This seems unlikely. There's no safety benefit.
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You are saying there's no safety to the equipment that was designed to run off 240VAC single phase, 120VAC - 0 - 120VAC split phase? Didn't we just go over all the dangers to doing that with the PDU? Surely there are dangers to the server as well. I cannot think of any other reasons as to why HPE would design the PSUs not to turn on at all if we tried feeding them 120VAC down the L/+ line, and 120VAC down the neutral line....
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There are no dangers with the individual power supplies. I think it extremely unlikely they designed them not to operate off split phase.
--- Quote from: Spork Schivago on May 18, 2018, 02:11:29 am ---
--- Quote from: Monkeh on May 18, 2018, 01:19:08 am ---
--- Quote from: Spork Schivago on May 18, 2018, 01:18:04 am ---the PSUs cannot run off split-phase. They won't power up, they won't provide power to the servers.
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And you know this how?
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By talking to HPE directly, instead of going through my VAR? I have a direct phone number I can give you, if you'd like to verify this information. I can PM you the part number to the PSUs and you can talk to them directly and ask them for yourself if you don't believe me.
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The answer will be given to me the same way it was given to you: A person on the other end of the phone with no knowledge whatsoever of power supplies reads '240V single phase' off the datasheet and says 'it will only work with this'.
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No, they did not just give me an answer. They went and checked the design specs, like they always do. This isn't consumer grade equipment, it's Enterprise Grade equipment. So like IanB was saying, 120-0-120VAC is common in North America and most products sold would be designed to work with that. Maybe with consumer grade equipment, yes. But most options I have available are 240V single phase or 3-phase or high DC voltage, which is used in telecommunication centers mainly (from what I've been told).
If the datasheet doesn't tell us and only lists supply voltage as 220VAC - 240VAC (not on just this, but some of the other equipment as well) and the manufacturer is claiming it will only work with 240VAC single phase, what would you do? Tear it apart to check and void the warranty and your really expensive equipment? Or would you assume they know what they're talking about, seeing how they're the ones who built it? Or would you just disregard them and wire it up for split-phase? After someone suggested that with the PDU, I almost did that, because I thought the people here knew what they was talking about, but I guess I didn't give enough info. I should have posted a datasheet or something, so they could see for themselves all the info. I do have some stuff I bought from Germany for my previous hobby, that was specially designed to run off USA power, but I had to specifically say I needed it for the North American wiring, and that's not really enterprise grade equipment. Just some Weller soldering stations, preheaters, hot air rework stations, etc. Nothing too fancy or expensive.
Enterprise grade hardware isn't the same as regular hardware you buy at Walmart or Home Depot.
Spork Schivago:
Output on those PSUs are 12v, 117 amp! That's a good amount of current.
Monkeh:
--- Quote from: Spork Schivago on May 18, 2018, 03:27:50 am ---But they checked. They just didn't give me an answer. They came back and said no, the power supplies would not even power on with split phase. So, there is a good chance that they have circuitry to detect the voltage.
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There's an equally good chance they didn't understand what the test setup was meant to be. Sorry, but I just can't see any reason whatsoever they'd care whether it's a single phase supply with a ground referenced neutral or not. Being Enterprise with a capital E doesn't change that.
--- Quote ---Heck, one of the options for my server is a DC power supply that supports 380VDC.
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That's what your 240VAC power supplies really run off. 240VAC rectified and boosted by a PFC controller to approximately 380VDC.
--- Quote ---It's fancy and supports other features as well, and maybe that's why split-phase won't work? They're HPE's Flex Slot Platinum Plus Hot Plug, 1400 watt, part number: 720620-B21
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It's.. a really ordinary power supply sourced from at least two manufacturers (Delta and Flextronics). People run these types of off split-phase all the time.
--- Quote from: Spork Schivago on May 18, 2018, 03:36:37 am ---No, they did not just give me an answer. They went and checked the design specs, like they always do.
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Design spec: 200-240VAC single phase. Your supply: 240VAC single phase. Yes, it's a split phase installation - the final load does not care about that detail.
--- Quote ---Or would you assume they know what they're talking about, seeing how they're the ones who built it?
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The ones who had multiple other companies independently design and manufacture a supply which is physically and electrically compatible. Nobody you spoke to specified, designed, tested, built, or was otherwise involved in the development of any of the several supplies with that part number.
This thread is going to keep going around in circles.
Change your PDUs for the type with double pole breakers and use your existing supply, or have an electrician (yes. really. please don't do it yourself.) install the transformer. Either will work.
Good luck with the heat problem.
--- Quote ---Enterprise grade hardware isn't the same as regular hardware you buy at Walmart or Home Depot.
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Where can I get Enterprise grade electrons for it?
IanB:
--- Quote from: Spork Schivago on May 18, 2018, 03:27:50 am ---It's fancy and supports other features as well, and maybe that's why split-phase won't work? They're HPE's Flex Slot Platinum Plus Hot Plug, 1400 watt, part number: 720620-B21
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OK, I did some reading around the HPE document library and the situation is clearer now.
This equipment is certainly intended for installation in commercial data centers and is not meant to see a home environment.
HP expects commercial power to be available in North America in two flavors of single phase: either 120 V AC ("low-line") or 208 V AC ("high-line"). The 208 V power would be derived from one leg of a three phase transformer and would be true 208-0 V single phase line to neutral.
HP does not expect 240 V AC single phase to be available in North America and their PDUs designated for the NA market are not specified this way. Their NA PDUs are specified for 200-208 V AC single phase input.
(Various flavors of three phase AC are also supported but they are not relevant here.)
The actual PSUs such as the HPE 1400W Flex Slot Platinum Plus Hot Plug Power Supply (720620-B21) that you quoted simply say "200-240 V, 50/60 Hz". There's nothing to indicate that the 240 V can't be derived from a split phase supply, but the split phase supply wouldn't be compatible with the PDU or the intelligent power management services.
So, in summary, what you have been told is correct. Your system needs a true 200-240 V AC single phase supply such as would be found in a commercial facility where it would come from one leg of a three phase utility transformer as 208 V AC. Since this is not available to you, you do indeed need a transformer to convert 240 V split phase to 240 V single phase line to neutral.
[Edit: Apparently I am wrong. The 208 V AC is not line to neutral, it is phase to phase with two hot legs and no neutral, similar to the 240 V split phase in a home. So maybe the transformer would not be needed if the P9S13A PDU were to be used instead of the P9S16A.]
Overall, your whole setup would work better in a commercial building.
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