How to wire up a 240VAC receptacle

[Gregg]

Actually Split-phase can be safer.

First you have GFCI or RCD to think about.
To reduce EMI or RFI X-cap's or Y-cap's are used. With two wire power and one side Neutral you are connecting 1/2 AC voltage to somethiing, the Neutral lead or safety ground. To work around this the GFCI or RCD has to be made less sensitive. With the center Neutral you have 0 volt AC EMI/RFI connected to Neutral so a more sensitive GFCI/RCD is possible..

There is no perfect wire so there is always a voltage drop on the Neutral lead making it NOT ground. A short from Neutral to something is connecting the voltage drop to something and not detected with fuse or circuit breaker in the hot lead. With split-phase this is detected. Shorts like this do happen and can have many watts of power turned in to heat.

Then you have 1/2 voltage difference to actual ground, again safer

The big cost is often just the one added wire and dual breakers.

Equipment designed for split-phase can be designed three ways.

1. You have Equipment that needs some 110-120 for internal use in addition to 220-240. Here three wire or safer 4 wire connection.

2. like above but with no 110-120 internal use so that the Neutral lead supplies no power.

3. A variation of #2 is Two hots and where Neutral lead is just used for a safety ground.

Three phase is just a shift to three hots vs two hots.

C

Three phase is far from just a shift to three hot leads.  There are several methods of connection used in the US, but all of the large data centers I have worked with use 480 volt 3ph UPSs connected to 208/120V transformers and then breaker panels.  Several customers had large cabinets that had 40 amp 208V 3ph power supplied.  3ph when rectified has far less ripple than single phase and the 3ph SMPS are more efficient.   

Neutral conductors should never be used as ground connectors.  True, there are a few cases where the NEC allows a ground conductor to carry a small neutral current; but I would never wire my house in such a manner, even if it is officially OK. 

Back to the subject at hand; Richard Crowley is absolutely correct and it is sad that Spork purchased the wrong PDU.  It isn’t our fault he didn’t ask first and now there isn’t any way to easily fix the situation short of taking it apart and seeing if it can be modified to install 2 pole breakers and to ensure the switching mechanism switches both hot legs of the 240V. 

If I were in Spork’s shoes, I would try to return the PDU on the grounds that they didn’t properly describe it in their literature and instead purchase two of the P9S13A units if he needs the capability to switch each branch circuit remotely. 

Let’s consider the possible unsafe modes of failure using the P9S16A PDU:

Suppose there is an internal ground fault in one of the server power supplies that is from the hot without the single pole breaker.  The single pole breaker doesn’t respond and the fault remains until the 40 amp two pole breaker trips after things catch fire.  Or the fault gets to the point where it blows up the power supply and possibly ruining the whole server.  If the 40 amp breaker trips, and nothing much else happens your whole system still goes down until you figure out the problem.  Assuming your server racks/cabinets are properly grounded; if they are not, you could be in for the shock of your life.

Suppose you figure out there is something wonky with one of the server power supplies and you turn it off remotely because you are not at home; but the PDU switch only turns off one hot leg.  Failure modes are the same as above.

I’m sure others on the forum could add to this list.

[james_s]

Same thing with 110 115 and 120, all of them acceptable.

In the US the nominal is 120 and 240, but it's quite common for people to say 110 and 220 Etc.

I'm not familiar with the UK at all, but I think their nominal voltage is 230 volts? But the specification allows anywhere from 220 to 240 or something like that.

*Except in some special cases, mainly on large equipment that has its own transformer built-in, then there are multiple Taps to get the voltage just right.

The nominal voltage in the US has gradually crept up over the years, I suspect to squeeze a bit more capacity out of the existing grid but I don't really know. In the early days it was 110/220, then it was 115/230, then it rose to 117/234, and finally to what it has been throughout most/all of my own life, the 120/240 that we have today. Quite a few people still refer to it by the old ratings though.

[Spork Schivago]

Note that "120VAC - 0 - 120VAC" is the same thing as "split-phase".

None of the HPE PDU are designed to handle split-phase.  They are all designed for schemes where Neutral = Ground.

If you connect any of those HPE PDU things to domestic split-phase where Neutral = 120VAC, you are setting up a situation that is dangerous for both equipment and people.

That is why a transformer is need to convert 120-0-120 ("split-phase")  into 240-0 ("single-phase")

I agree the transformer is needed.   That's why I posted that in my second post I think.   I just wasn't sure what transformer.   But then people started suggesting that I should rewire the PDU, etc.

I called HPE again and verified that we do need the 1400 watt PSUs that only come in 240VAC single-phase.   I had asked you if 120-0-120 was split-phase and you said NO!!!!   So that confused me a bit, but I think I worded it weirdly.

Sending back the PDU and replacing it with a PDU that handles split phase isn't an option because the PSUs cannot run off split-phase.   They won't power up, they won't provide power to the servers.   So, we need the transformer, even if people think it's a hack job or dangerous or stupid or whatever.   That appears to be our only option at this point.

[Monkeh]

the PSUs cannot run off split-phase.   They won't power up, they won't provide power to the servers. 

And you know this how?

[Spork Schivago]

Looks like you like to ignore simple facts.

In the USA the standard electrical outlet is 110-120 volts 60hz.

All 220-240 volt stuff uses different connectors. Because of the difference people take more care.

Think of how many people in the USA have used computer power cords. For the USA the end that connects to a computer is 115volts. For a lot of the world that is 220volts but not in USA.

So now you have people seeing the computer end thinking 115volts and connecting an extension cord to your PDU, but that is not 115 volts. A part of safe is knowing what to expect.
So what is a safe European standard is not as safe in the USA due to common thought.

The added transformer is creating a safe NON-USA standard in addition to wasting power. That transformer will get hot, and that is a waste of power. 

One thing you might like to know is that 220 volt 60hz is more dangerous then 220 volt 50hz. The 60hz has a greater chance of messing up your heart beat then 50hz.

If you want real safe 220 volts using a USA split phase( 220 Volts with a neutral center tap) you use a four wire connection. The forth connection the safety ground.
Unlike the rest of the world USA 220 volt equipment often has some 115 volt loads.

C

We need 240VAC, again, for the server, not 220VAC, although it would run on 220VAC.   Most of our equipment is NOT from the USA.   The cords to power these devices are NOT what you find with a NORMAL USA bought PC, so I highly doubt anyone who is allowed to be around the rack will try plugging anything into the PDU.    I mean, simple fact, strangers aren't going to be down here, and if they are, they're breaking the law.   Eventually, we have to worry about my daughter, but that's a long ways away, and even then, she cannot physically get into the rack to plug anything into the PDU.   Ohm's law shows us if we double the volts, we cut the current draw in half.   200v * 2 amp = 400 watts.   20 amp * 20v = 400 watts.    I think I'd rather get shocked, if I had to get shocked, at the 200v, 2 amp, rather than the 20 amp.

I have no idea how anyone is going to plug any cords into the PDU, I don't know what you think the inputs look like, but you physically cannot take a normal PC cord and plug it into the PDU.   You need special cords....most of our energy hungry equipment is designed to run off 240VAC, but most of it can go down to 100VAC.   I mean, we have some American made workstations, but they're not going into the rack at all, and aren't being powered by this PDU.   A lot of stuff came from Germany.   There's usually no switch on these pieces of equipment to flip.   They say 100VAC - 240VAC.

I mentioned in a previous post that security was our responsibility and we get audited, where some people from some companies come in and check to make sure everything is up to their standard.   We get a report on what needs to change, if anything, and it's our responsibility to change what they list.   Once we wire up the 15kVA transformer (or higher someone to wire it up for us), we'll have to have yet another one of those pesky audits.

There's security in place.  Maybe you can take comfort in knowing that currently, no one who is specifically supposed allowed in the datacenter can get into the datacenter without doing a lot of illegal work?   This isn't a playroom.   The idea is though, we do our own thing once these contracts are up, and hopefully, later on in life, our daughter takes interest.   If not, that's okay, we'll love and accept her no matter what.   That's years down the road before we burn that bridge though.

Heck, do you know how hard it was to say no to the three phase installation?   We were talking over 50,000$ and almost went for it, because then we can purchase stuff that's a bit more suited to our task at hand.   I feel better having a PDU hooked up with a backup sitting on the shelf in case one shits the bed, rather than daisy chaining a whole bunch to try and get my systems running.

220 230 and 240 volts are all the same.
Voltage wise all of those are acceptable. *

Same thing with 110 115 and 120, all of them acceptable.

In the US the nominal is 120 and 240, but it's quite common for people to say 110 and 220 Etc.

I'm not familiar with the UK at all, but I think their nominal voltage is 230 volts? But the specification allows anywhere from 220 to 240 or something like that.

*Except in some special cases, mainly on large equipment that has its own transformer built-in, then there are multiple Taps to get the voltage just right.



Sent from my Moto x4 using Tapatalk

Yes, and our power supplies can take anything from 220VAC - 240VAC, but run optimally with 240VAC.   Thankfully, here, we actually have 120VAC when I measure the receptacles and not 115VAC.   The transformer will be an Edison, but they're literally the exact same thing as Acme Electronics.   Same catalog number, everything.   Hopefully, the transformer will put out 240VAC and not something lower, like 220VAC or 230VAC.

[Spork Schivago]

IMHO while I think you could install this with minimal problems you really should get an electrical engineer or commercial electrician that is familiar with something along these lines to have a plan drawn up and run it past your electrical inspector for the city and make sure everything will be okay.

You seem very concerned with security and Audits and having it done as right as it can be and all of that stuff;
 so having this planned out by a professional and approved by the inspector before you start doing things would be highly important. IMO

I would bet your insurance is going to absolutely require that.



Sent from my Moto x4 using Tapatalk

Yes, even though I'll be installing it, I'm going to be running it by professionals before I actually even touch anything.   It's out of my league a bit, and I will learn, but because of the dangers involved, I have no choice but to run it by professionals first.   Heck, I'm still having a hard enough time trying to understand how to wire it properly to begin with.   I will not take chances and just randomly guess or say yeah, I think this is right.   I just thought that was assumed, but yeah, that's the plan and was from the git go.   I might be able to get the company in my city that I'm working with to send one of their guys over, I dunno.   But I still want to wire it up, I don't want them doing it for me.   I just need them to double check everything and make sure it's correct before I go to the city, and watch me while I'm wiring it up, to make sure I don't make any horrible mistakes.

[Spork Schivago]

Mr. Crowley certainly has more patience than I. 
When stated that

“None of the HPE PDU are designed to handle split-phase.  They are all designed for schemes where Neutral = Ground.”

I believe He may have overlooked the P9S13A, as I previously posted, states it is for North America and Japan as it is rated for 200 -240V, uses a standard L6-30P plug (208-240V 3 pole twist lock labeled L1, L2 and Ground in the USA) and it has 2ea 2pole 20a breakers, one for each level of the PDU.  It also has the exact same receptacles as the one chosen by Spork. 
I’m not trying to rag on Mr. Crowley here, but I still think two of the P9S13A deserve more consideration especially since Spork has stated that he may expand his power requirements.  It would eliminate the need for a transformer unless his servers specifically need a grounded neutral which is very doubtful for SMPS typical server power supplies. 
Bratster’s drawing is a fine example of how to install a transformer; with the breaker panel on the output and proper breakers installed I believe it would pass any reasonable inspection.  However there are inspectors out there that kind of make up their own rules.

I appreciate the suggestion again for the P9S13A, but as Mr. Crowley had previously stated (which I was unaware of), these PDUs put out what they're fed.   So if they're fed a split-phase 120VAC - 0 - 120VAC source, they're going to output a split-phase 120VAC - 0 - 120VAC source, thus, we would not be able to use it.   We would still need the 240VAC - 0 - 0 for the PSUs (Power Supplies) that are in the servers.   If that makes since to you.   Unless I am misunderstanding something, and the P9S13A can actually provide single phase 240VAC on the output....

[Spork Schivago]

Certainly Spork would be better off with something he can connect directly to his split-phase domestic service as @Gregg observes.  It seems unfortunate that he selected that particular PDU.  The "documentation" provided by HPE leaves a great deal to the imagination from lack of useful details.

It's not like we actually just randomly picked a PDU Mr. Crowley.   We had a power assessment done for the server and where told we could only power our servers with one model PSU, which is 240VAC single-phase.    Then, after that, the HPE technicians found a suitable PDU for our rack environment.   I let those people make the decisions like that, so if something goes wrong, it falls back on them, not me.    But according to them, anything less than 1400 watt, our servers aren't going to power on at all with the hardware that we have in there.   And for the PSU, there was only one choice they provided us with, which expects the 1-phase 240VAC.    I mean, to use a split-phase service, we'd have to ditch some hardware, or go through another company.

We cannot mix and match equipment either, or it voids the warranty.   I don't necessarily mean we cannot go for a PDU made by a different company, but because we have HPE servers, we need to use HPE RAM, HPE Power Supplies.   If we don't, and something breaks, even if it's not related to us using something that isn't HPE branded, they will use that as an excuse to not warrant the hardware.   (one of those, oh, we see you're using non-qualified power supplies.   We're not going to replace your broken really expensive CPUs because you used unapproved PSUs.   For all we know, those PSUs killed your CPUs).

[Spork Schivago]

Actually Split-phase can be safer.

Yes, that all may be true, but none of it is beneficial (or even relevant) to the specific case at hand.
Bottom line: The PDU appears to be designed to have Neutral = ground and connecting split-phase to it is dangerous.

And would be not only dangerous, but wouldn't work.   The equipment that the PDU powers is designed to run off 1-phase 240VAC.   Now, if we were to hook up some workstations (not desktop's, but actual workstations), they might be designed to run off split-phase or even 120VAC.   The switch is made to run off single phase (either 120VAC or 240VAC) but not split-phase 120VAC - 0 - 120VAC.   I don't know if it'd turn on at all if we tried, but it isn't right.

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.

I don't like using a 240VAC transformer anymore than some of you guys, but I don't see any other options here, unless we ditch all the money we've invested in all this very expensive equipment and go for another vendor, but chances are even then, we'll need the single phase 240VAC.    Unfortunately, when you're dealing with equipment that requires a lot of power and is commercial grade, there aren't too many options.   It was hard enough just finding stuff that wasn't designed for 3-phase.   Most of the stuff was for 3-phase.   It would have been easier, but much, much, much more expensive, to have 3-phase ran to the house, and then purchase the 3-phase equipment.

[Monkeh]

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.

This seems unlikely. There's no safety benefit.

[Spork Schivago]

Actually Split-phase can be safer.

First you have GFCI or RCD to think about.
To reduce EMI or RFI X-cap's or Y-cap's are used. With two wire power and one side Neutral you are connecting 1/2 AC voltage to somethiing, the Neutral lead or safety ground. To work around this the GFCI or RCD has to be made less sensitive. With the center Neutral you have 0 volt AC EMI/RFI connected to Neutral so a more sensitive GFCI/RCD is possible..

There is no perfect wire so there is always a voltage drop on the Neutral lead making it NOT ground. A short from Neutral to something is connecting the voltage drop to something and not detected with fuse or circuit breaker in the hot lead. With split-phase this is detected. Shorts like this do happen and can have many watts of power turned in to heat.

Then you have 1/2 voltage difference to actual ground, again safer

The big cost is often just the one added wire and dual breakers.

Equipment designed for split-phase can be designed three ways.

1. You have Equipment that needs some 110-120 for internal use in addition to 220-240. Here three wire or safer 4 wire connection.

2. like above but with no 110-120 internal use so that the Neutral lead supplies no power.

3. A variation of #2 is Two hots and where Neutral lead is just used for a safety ground.

Three phase is just a shift to three hots vs two hots.

C

Three phase is far from just a shift to three hot leads.  There are several methods of connection used in the US, but all of the large data centers I have worked with use 480 volt 3ph UPSs connected to 208/120V transformers and then breaker panels.  Several customers had large cabinets that had 40 amp 208V 3ph power supplied.  3ph when rectified has far less ripple than single phase and the 3ph SMPS are more efficient.   

Neutral conductors should never be used as ground connectors.  True, there are a few cases where the NEC allows a ground conductor to carry a small neutral current; but I would never wire my house in such a manner, even if it is officially OK. 

Back to the subject at hand; Richard Crowley is absolutely correct and it is sad that Spork purchased the wrong PDU.  It isn’t our fault he didn’t ask first and now there isn’t any way to easily fix the situation short of taking it apart and seeing if it can be modified to install 2 pole breakers and to ensure the switching mechanism switches both hot legs of the 240V. 

If I were in Spork’s shoes, I would try to return the PDU on the grounds that they didn’t properly describe it in their literature and instead purchase two of the P9S13A units if he needs the capability to switch each branch circuit remotely. 

Let’s consider the possible unsafe modes of failure using the P9S16A PDU:

Suppose there is an internal ground fault in one of the server power supplies that is from the hot without the single pole breaker.  The single pole breaker doesn’t respond and the fault remains until the 40 amp two pole breaker trips after things catch fire.  Or the fault gets to the point where it blows up the power supply and possibly ruining the whole server.  If the 40 amp breaker trips, and nothing much else happens your whole system still goes down until you figure out the problem.  Assuming your server racks/cabinets are properly grounded; if they are not, you could be in for the shock of your life.

Suppose you figure out there is something wonky with one of the server power supplies and you turn it off remotely because you are not at home; but the PDU switch only turns off one hot leg.  Failure modes are the same as above.

I’m sure others on the forum could add to this list.

This is getting old guys.   It's not like I just surfed the net and randomly picked a PDU.   I'm running a business, so I call one of my VARs, I tell them what our requirements are.   They place a call to one of the various companies.   I like HPE, so I wanted HPE.   At first, we didn't have income to purchase everything we needed.   This is how most start-up companies operate.   They don't make a return for 2 years or so.   We got lucky and made a return early on, which allowed us to purchase the upgrades to do what we wanted.   But then we called our VAR and said hey, because we have x, y, and z added to the servers now, will the 120VAC 500 watt PSUs that are currently in the servers handle the new load?   They say let me forward that along to our HPE technicians.    They come back and say no, you need the 1400 watt PSUs part number <blah>.   We purchase the PSU part number <blah> and they say you also are going to need the PDU part number <blah>.    Our only other option was 3-phase, and if anything, we should be saying it's sad that Spork couldn't afford to get 3-phase ran to his house so he could purchase the 3-phase equipment that would be available to him.   We also need a UPS, but eventually a whole home generator with an automatic transfer station.

It'd be like me saying it's sad that you are running 3-phase to your rack.   You made a mistake in purchasing your equipment and should be running split-phase to your rack.   Your rack cannot handle split-phase, it needs 3-phase.   Why?   Because the equipment was designed for 3-phase, just like our equipment was designed for 240VAC single phase, not 120VAC - 0 - 120VAC split-phase.

I thought this was a simple question, I didn't expect 6 pages of people trying to get me to switch to something that just won't work, and granted, I guess it's more my fault for not giving out enough information (such as the power supplies we use, the exact equipment we use, etc), but my fear is violating the NDAs that we signed.   There's some claus that talks about us paying a lot of money if we violate it.    We have people working for us that have to sign an NDA, but we as well had to sign NDAs.   We have on-site and off-site record storage where there's different levels that different employees have access to.   There's the TRADE SECRET level, the CONFIDENTIAL LEVEL, and then the GENERAL level.   Our employees get access to the GENERAL level documents, which include stuff such as how to connect to the VPN tunnel, how to use the two factor authentication properly, what to do if there is a suspected compromise, SOPs, etc.

I don't know why everyone assumes I purchased the wrong PDU.   I don't know why almost everyone is suggesting I switch to a PDU that supports split-phase.   I said I need 240VAC single-phase and that's what I need.   I just thought in a professional environment, there'd be a lot less this is what I think you need stuff going on or if it was me, I would have done it this way or that way, or for my situation, split-phase works best, therefore, for your situation, it does as well kinda stuff.   I just thought I'd get a nice answer saying this is how you can achieve single phase 240VAC, like Mr. Crowley suggested, and a few others.

[Spork Schivago]

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.

This seems unlikely. There's no safety benefit.

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....

[Spork Schivago]

the PSUs cannot run off split-phase.   They won't power up, they won't provide power to the servers. 

And you know this how?

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.

[IanB]

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.

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.

[Monkeh]

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.

This seems unlikely. There's no safety benefit.

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....

There are no dangers with the individual power supplies. I think it extremely unlikely they designed them not to operate off split phase.

the PSUs cannot run off split-phase.   They won't power up, they won't provide power to the servers. 

And you know this how?

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.

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'.

[Spork Schivago]

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.

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.

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]

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.

This seems unlikely. There's no safety benefit.

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....

There are no dangers with the individual power supplies. I think it extremely unlikely they designed them not to operate off split phase.

the PSUs cannot run off split-phase.   They won't power up, they won't provide power to the servers. 

And you know this how?

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.

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'.

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]

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.

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.

Heck, one of the options for my server is a DC power supply that supports 380VDC.

That's what your 240VAC power supplies really run off. 240VAC rectified and boosted by a PFC controller to approximately 380VDC.

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

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.

No, they did not just give me an answer.   They went and checked the design specs, like they always do.

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.

Or would you assume they know what they're talking about, seeing how they're the ones who built it?

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.

Enterprise grade hardware isn't the same as regular hardware you buy at Walmart or Home Depot.

Where can I get Enterprise grade electrons for it?

[IanB]

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

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.

[Spork Schivago]

You still don't get it.   We still have other equipment that requires 1-phase 240VAC, unless the technicians lied about that as well.   The people I talked to tonight was to _verify_ the information.    Pre-Sales is a hell of a lot different than post-sales.   Post sales are the REAL HP technicians that are actually building the units, the ones that my VAR deals with.

My VAR is a large VAR.   They have Microsoft people in the building, they have HPE technicians in the building, building HPE stuff, they have Lenevo people in the building.   These people are paid by HPE, Lenevo, etc.   I can have my Account Executive double check with the actual technicians that build the actual devices and have him tell me, once again, that it'll only run on 1-phase 240VAC.   I dunno why they did that.

If you feel there isn't a difference between enterprise grade and consumer grade equipment, I'm sorry, but you're just wrong.   With your datacenter, would you go buy a Vizio router for the gateway?   I highly doubt it.   You were the one who posted the datacenter pics with the three-phase, weren't you?   I would think out of everyone, you'd understand the most that most of the equipment you purchased is designed to run off 3-phase, not split phase or any of that shit.   Same with mine.   But you're right, going around in circles.   I'm still not 100% clear on how to wire the AC into the transformer.

Once again though, I will state, I am still getting a professional to go over the results before I hook anything up.   I'm not an idiot, and only an idiot would try to hook a transformer like this up without having any knowledge of how it works without seeking professional help first.   I've been saying that this whole time.   I just want to be the one who physically does the work and learns how it works (the transformer).   I've learned a lot from you guys since I posted.

When I said fancy features, I meant HPE Power Discovery Services (PDS) combines the HPE Intelligent Power Distribution Unit (iPDU) and HPE Flex Slot Platinum Plus power supplies with HPE Insight Control software to create an automated, energy-aware network between IT systems and facilities.

I could not go for the HPE Intelligent Power Distribution Unit.   So I cannot use that feature.   However, there's extra stuff near the adapter plugin that interacts with the iPDUs and sends information over the network and everything.

So before you leave, can you go over this PFC Controller a bit more?   How do people get 380VDC ran into their house / building, and why is it rectified and boosted to such a high voltage?   The output of the PSU is 12VDC.   Where does the 380VDC come into play?

Thanks.

[IanB]

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.

It's not clear that there are any HPE PDUs with double pole breakers. The HPE literature divides the product range into two categories: NA/Japan which expects 200-208 V AC single phase, or INTL which expects 220-240 V AC single phase. In either case it is clear that this voltage is measured line to neutral, as is typically found in commercial premises.

[Spork Schivago]

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

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.

Overall, your whole setup would work better in a commercial building.

THANK YOU!!!!   That's what I've been trying to say!   I didn't know I'd have to go into sooooo much detail to get people to understand.   Yes, this equipment is designed for a COMMERCIAL building, not HOME!!!   But the problem is getting 208VAC to our house.   That's just as expensive as any of the other 3-phase, hence the reason we had to go with the 240VAC European factor.    Normally, a commercial facility would have 3-phase.    It's that iPDU stuff, I believe, that makes this PSU NOT boot up with split-phase, despite what other people say.   It gets frustrating repeating myself, but thank you for doing the research!   I got hurt in the Marine Corps.   It caused some brain damage.   My brain doesn't work the same way as other people, so it's hard to word things properly or talk properly sometimes and I cannot get the right words out, no matter how much I try.   This makes it frustrating and people always think I'm being an ass, but I'm not trying to be, I'm just trying to explain it the best I can.

But it's weird, although I can't tell people how to do certain things or remember, I can still do them very well, much better than before, like programming.   I don't know how.   The memory specialist doc I saw said it's like losing a sense, the other senses tend to get better.   Part of my brain don't work right or at all, so he thinks other parts work better I guess.

Anyway, now that we finally got that out of the way and almost everyone can agree that I need true 240VAC 1-phase, can we get back to the transformer issue?   I'm still having a hard time understanding it.   Do you guys have any good documents that break down how they work and what taps are and stuff like that?

[Spork Schivago]

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.

It's not clear that there are any HPE PDUs with double pole breakers. The HPE literature divides the product range into two categories: NA/Japan which expects 200-208 V AC single phase, or INTL which expects 220-240 V AC single phase. In either case it is clear that this voltage is measured line to neutral, as is typically found in commercial premises.

Yes, hence the reason we could ONLY go for the 240VAC PDU!   The 3-phase is too expensive.   I mentioned that early on, but maybe my message wasn't clear?   I said most of the equipment is for 3-phase, but after talking to the electricity company and the professional licensed electrician, we could not afford it.   So we had to go with the 240VAC one.   I was saying the Enterprise grade stuff is not like the residential stuff.  But for some reason, people just don't understand that.   Thank you for helping me word things correctly!

[IanB]

So before you leave, can you go over this PFC Controller a bit more?   How do people get 380VDC ran into their house / building

(they don't...)

, and why is it rectified and boosted to such a high voltage?   The output of the PSU is 12VDC.   Where does the 380VDC come into play?

The 380 V DC is apparently a standard found in commercial data centers. The 380 V DC is created inside the building from the normal AC supply, it is not brought in from outside.

As to why it would be used, this is about how power supplies work. In order to get the 12 V DC, a power supply first rectifies the AC into high voltage DC, and then special electronics take the high voltage DC and convert it down to the 12 V. Instead of each power supply individually rectifying the AC, it is more efficient to have a single giant rectifier somewhere in the building and then distribute this around to all the servers.