How to wire up a 240VAC receptacle

[Richard Crowley]

So when HP speaks of 1-phase and lists NA/JP for the models, they're really meaning split-phase, for the higher than 120VAC PDUs, correct?   

NO!!!!  Single-phase (or "1-phase")  NEVER means the same thing as "split phase"  Single-phase (at least here in North America) implies that one side ("Line") is "HOT" and the other side ("Neutral") is essentially at zero-potential (i.e. GROUND).  In North America, the convention is that Neutral (white wire) is connected to Ground (green wire) at the breaker panel.  And the equipment is designed on the assumption that Neutral will be effectively at zero volts.  If you connect it to 120V you are just asking for trouble.

And split-phase is what we have coming into our house, not 1-phase, right?   120VAC - 0 - 120VAC. 

Each side (120VAC to neutral/ground) is a "1-phase" circuit.  What you have coming into your house (and virtually everyone's house in North America) are two "single-phase" circuits.  You can get 240V from one "phase" to the other because of the North American convention established long before we were born.  But those two sides are not REALLY "phases".  Electricians call them "phases", but electronic engineers do NOT call them "phases" because they are not.

Appliances that are designed to operate on 240V in North America are designed to have the two 120V sides at 120V above ground.  They are typically resistive heaters (water heaters, forced air furnaces, cook-stoves, ovens, etc.)  And BOTH sides are well insulated and assumed to be always HOT. 

But what you have is a piece of industrial equipment that was designed with the assumption that it would be connected to a source of GROUND_REFERENCED 240V. That is what THEY mean by "single-phase".  Your PDU was designed on the assumption that the Neutral line will be essentially zero volts.  Connecting it to 120V is a monumentally terrible idea.  Before you identified what your mystery load was, we were assuming that it was some kind of gadget that might operate on "split-phase power.  Perhaps a domestic welder or air-compressor, etc.

But you have a sophisticated piece of industrial equipment which has a bunch of sensitive and expensive loads (computers) connected to it. And that is a whole different ball-game.

I would rather try wiring it up myself, properly.

 
By operating a business in your home, you create a hugely gray area.  Technically you should take out a permit and have an inspection.  Else your can cancel your fire insurance because they won't pay off if you have done something like this and your house goes up in flames.  Be sure and have a good off-site daily backup/archive scheme in operation.

Are you familiar with the brand name at all?   Are they any good?

I would feel perfectly comfortable using that transformer if I were in the position of needing something like that.  If you have any qualms, be sure and buy a transformer with proper approval stamps (UL, etc.)  See Dave's recent video on this topic.

When I said Where I wouldn't be violating any codes, I was speaking strictly about the NEC, not the modifications (more like additions, from how I read the rules) that my local jurisdiction (Steuben County) can make to the NEC.   Would this violate any of the NEC that all states must follow?   If I cannot get passed that, there's no point going to my local governmental jurisdiction.   As I understand it, they can add to the NEC, but they cannot remove stuff from the NEC.   So if it fails the NEC right  now, no matter where I live in the USA, no local governmental jurisdiction can modify the NEC in such a way where it'd pass.

That is why getting a plan from a licenced professional engineer will help you do something that is legal.

You won't find big industral transformers like that with "IP" ratings.  They are designed for harsh, outdoor conditions.  They are not designed to be impervious to water, they are designed to operate with rain-water washing through them.  I can't imagine that there is any condition in your basement that would exceed what they would face every day outdoors. Of course, this assumes proper installation where the outer case is very well bonded go a good earth ground.  Because the transformer is completely enclosed in a ground steel case, it should be safe from animals and children.

Finally, is 7.5KVA the correct rating for this unit? 

Dunno?  What is the power rating of the (unidentified) loads NOW?  What are your expansion plans?  If you are already starting out with 5KW load, then perhaps it might be wiser to get a 10KVA (or 15KVA) transformer.

 Of course, this also begs the question how much power do you have coming into your house from the electric utility?  Typical domestic service that I have seen is 240V @ 200A which is 48KVA (minus what the rest of your house uses).  Do you have/need air-conditioning for all this?  Remember that when it comes down to it, a computer is just a really expensive heater.  If your computer uses 1000W, then you need enough air conditioning for a 1000W heat source.  So a rule of thumb is to plan on enough power to keep everything cool as well as powering it.

[Richard Crowley]

Also, that transformer lists the input as 240,480VAC.   It also lists it as single phase.   240x480 on the primary, 120x240 on the secondary.   With it being one phase, wouldn't that put us in the same predicament that we're in now?   Or am I misunderstanding something here?

That is a single-phase transformer.  There is only one core.  Than makes it single phase.  All the input (primary) and output ( secondary) wires are isolated from ground so that you can connect it whichever way you need.  You can connect the primary to anything from 216 to 504 volts.  And you can wire the secondary for either 120V or 240V.

So I'd connect the primary lines to H1-H3 and H2-H4, then I'd connect the secondary lines to X1 - X4?

No, you will blow up the transformer and burn down your house if you do that.

You need a straight-across, 1:1 transformer from your 240V "split-phase" source to a 240V, ground-referenced single-phase output.

The table shows that for 240V input, one side goes to H1 and H7 connected together, and the other side goes to H10 and H4 connected together
And the table shows the for 240V output it comes from X1 and X4, with X2 and X3 connected together.

If you connect X1 to ground, then X1 becomes "Neutral" and X4 is the source of your ground-referenced 240V SINGLE PHASE.

Please note that I am NOT a professional electrician, and I am not a licensed practicing engineer.  You should seek competent advice from a professional licensed in your jurisdiction.  High-power engineering advice, like legal advice is never completely reliable from a stranger on the internet.  Just common sense.

[Gregg]

I cannot use the P9S13A's.   That's 208VAC outlets.   I need 220VAC+.

The HPE P9S13A shows on page 8 of the HPE G2 Switched Power Distribution Units.PDF as having input of 1-ph 200-240V 24 amps with L6-30P plug on the cord.  It has the same footprint, the same outputs as the P9S16A.  The two are probably exactly the same except for input cable, plug and internal breakers. 
There is zero chance that the P9S13A can magically reduce the input voltage of 240 down to 208 volts.
The HPE website is anything but user friendly and seems like it is a product of marketing with almost total disregard for engineering; in other words, business as usual.  The places that state it is 200-208V are most likely cut and paste errors by the person that made the document.

[Richard Crowley]

The places that state it is 200-208V are most likely cut and paste errors by the person that made the document.

208V is a very common mains voltage in 3-phase power distribution.  As is 277V. 
They seem odd to us who mainly see single-phase utility power.

[C]

With
P9S16A
HPE G2 Swtd 7.3kVA/60309 2U INTL PDU

In the USA in a house, I see one of three things happing.

1. You burn your house down and insurance will not cover loss.
2. You get someone hurt, probably criminal charges.
3. You destroy some equipment.

HP lists four major categories of models

220-240V Input, Single Phase, International
Not a standard in USA.

200-208V Input, Single Phase, North America/Japan
Is using one phase of a three phase power source. Only industrial not in a house.

100-240V Input, Single Phase, Worldwide

This only matches the 110-120 used in USA.
And
HP makes a model for this
100-120V Input, Single Phase, North America/Japan

USA's 220-240Volt house standard does not match any of above.
As has been stated many times it is split phase with two hots and a common or center tap.

So the outlets of P9S16A with a transformer will still be non-standard in the USA and that will probably get someone/thing hurt!

C

[Bratster]

Also one thing to keep in mind regarding the term International, it doesn't always mean the world.

If it's a US company using the term International it's can mean the rest of the world, not the US.

HPE may be using the term in that sense,
So that power distribution unit is intended for everywhere but the US.

And I would think it's just a typo on their part that the 208 volt USA model wouldn't also be able to do 240 volt USA.
But again that's up to them to answer.

Sent from my Moto x4 using Tapatalk

[dmills]

Almost certainly the "208V" model is the one you want for a 240V split phase service, but you will need to check that with HP (It also has the US plug that your sparks should be happy to install a socket for).

It will output 240V split phase (No neutral) just the same as it is input, these are not any kind of voltage converter, just breakers relays and load measurement hardware. 

Regards, Dan.

[Spork Schivago]

So when HP speaks of 1-phase and lists NA/JP for the models, they're really meaning split-phase, for the higher than 120VAC PDUs, correct?   

NO!!!!  Single-phase (or "1-phase")  NEVER means the same thing as "split phase"  Single-phase (at least here in North America) implies that one side ("Line") is "HOT" and the other side ("Neutral") is essentially at zero-potential (i.e. GROUND).  In North America, the convention is that Neutral (white wire) is connected to Ground (green wire) at the breaker panel.  And the equipment is designed on the assumption that Neutral will be effectively at zero volts.  If you connect it to 120V you are just asking for trouble.

And split-phase is what we have coming into our house, not 1-phase, right?   120VAC - 0 - 120VAC. 

Each side (120VAC to neutral/ground) is a "1-phase" circuit.  What you have coming into your house (and virtually everyone's house in North America) are two "single-phase" circuits.  You can get 240V from one "phase" to the other because of the North American convention established long before we were born.  But those two sides are not REALLY "phases".  Electricians call them "phases", but electronic engineers do NOT call them "phases" because they are not.

Appliances that are designed to operate on 240V in North America are designed to have the two 120V sides at 120V above ground.  They are typically resistive heaters (water heaters, forced air furnaces, cook-stoves, ovens, etc.)  And BOTH sides are well insulated and assumed to be always HOT. 

But what you have is a piece of industrial equipment that was designed with the assumption that it would be connected to a source of GROUND_REFERENCED 240V. That is what THEY mean by "single-phase".  Your PDU was designed on the assumption that the Neutral line will be essentially zero volts.  Connecting it to 120V is a monumentally terrible idea.  Before you identified what your mystery load was, we were assuming that it was some kind of gadget that might operate on "split-phase power.  Perhaps a domestic welder or air-compressor, etc.

But you have a sophisticated piece of industrial equipment which has a bunch of sensitive and expensive loads (computers) connected to it. And that is a whole different ball-game.

I would rather try wiring it up myself, properly.

 
By operating a business in your home, you create a hugely gray area.  Technically you should take out a permit and have an inspection.  Else your can cancel your fire insurance because they won't pay off if you have done something like this and your house goes up in flames.  Be sure and have a good off-site daily backup/archive scheme in operation.

Are you familiar with the brand name at all?   Are they any good?

I would feel perfectly comfortable using that transformer if I were in the position of needing something like that.  If you have any qualms, be sure and buy a transformer with proper approval stamps (UL, etc.)  See Dave's recent video on this topic.

When I said Where I wouldn't be violating any codes, I was speaking strictly about the NEC, not the modifications (more like additions, from how I read the rules) that my local jurisdiction (Steuben County) can make to the NEC.   Would this violate any of the NEC that all states must follow?   If I cannot get passed that, there's no point going to my local governmental jurisdiction.   As I understand it, they can add to the NEC, but they cannot remove stuff from the NEC.   So if it fails the NEC right  now, no matter where I live in the USA, no local governmental jurisdiction can modify the NEC in such a way where it'd pass.

That is why getting a plan from a licenced professional engineer will help you do something that is legal.

You won't find big industral transformers like that with "IP" ratings.  They are designed for harsh, outdoor conditions.  They are not designed to be impervious to water, they are designed to operate with rain-water washing through them.  I can't imagine that there is any condition in your basement that would exceed what they would face every day outdoors. Of course, this assumes proper installation where the outer case is very well bonded go a good earth ground.  Because the transformer is completely enclosed in a ground steel case, it should be safe from animals and children.

Finally, is 7.5KVA the correct rating for this unit? 

Dunno?  What is the power rating of the (unidentified) loads NOW?  What are your expansion plans?  If you are already starting out with 5KW load, then perhaps it might be wiser to get a 10KVA (or 15KVA) transformer.

 Of course, this also begs the question how much power do you have coming into your house from the electric utility?  Typical domestic service that I have seen is 240V @ 200A which is 48KVA (minus what the rest of your house uses).  Do you have/need air-conditioning for all this?  Remember that when it comes down to it, a computer is just a really expensive heater.  If your computer uses 1000W, then you need enough air conditioning for a 1000W heat source.  So a rule of thumb is to plan on enough power to keep everything cool as well as powering it.

Because of the money we have invested in equipment at this point in time, I do not feel comfortable discussing publically what the loads are, however, if you would like to know, I would more than happy to PM you.   I would love it if one of our servers drew 1,000 watt!   That'd be nice.   As for the cooling, eventually we will get central air, but right now, being in the basement, we've kinda got lucky.   Throughout the year, it seems to maintain an almost stable temperature and is cool.   We have sensors for the rack, that monitor humidity, temperature, water / moisture, etc.

I am glad that you explained the IP rating a bit more in detail.   Going off that paper, it's easy for me to not fully understand how safe it is.   By reading the rating of IP14, I thought, oh no!   This isn't what I want at all!   But after what you said, it seems IP14 is perfect.

I'm still a bit confused about the phases here.   I understand how the 240VAC works in the US.   120VAC to neutral, 120VAC to neutral, 240VAC going from hot to hot.    I understand the breaker panel, I've studied it and the various names.   I know the ground buss-bar and neutral buss-bar's are connected with a jumper wire usually.   I know there's a hot buss bar where every other connector runs off the other incoming main line.

For example, the first single pole breaker, #1, runs off the first of the two incoming main 120VAC hot lines.   #3 (directly below it), runs off the second of the two incoming main 120VAC lines.   #5 runs off the first, etc.   This is why when we install double-pole breakers, we can get 240VAC from hot to hot, instead of just 120VAC.

If I were to somehow attempt to create my own 240VAC source by using single pole breakers #1 and #2, it shouldn't provide 240VAC, from my understanding (I've never attempted), but should provide 120VAC, because they're on the same "phase".

So, if what we have is called 1-phase, but not by electrical engineers, what is it called by electrical engineers, and what is split-phase?    I thought split phase was the whole 120VAC - Neutral (or ground) - 120VAC, giving us 240VAC....

I thought split-phase was where the hot was split between two wires, each 180 degrees out of phase.   When one was at 120VAC, the other was at -120VAC, giving us 240VAC.

Also, in the first post, I believe, I did mention that it was a PDU for my server rack, because I realize even the name PDU could mean multiple things, and it's important that you guys knew I was referring to a power distribution unit for a rack, holding expensive computer equipment.

Finally, because we are running a business, have a daughter, living in the city, etc, we will always follow the law, and get the proper permit, after drawing up our design, and have it inspected.   In the country, where we used to live, when I ran the 240VAC to my BGA rework station, we had tried, but the city inspector didn't really care about the country, which we thought was odd.   Technically, we were living in the Town of Country, not the City, but they said generally, in the country, you just wire it up or hire someone to wire it up.   They wouldn't actually come up to inspect my work.   I thought that was horrible and should have been reported.

I still want to wire the transformer myself.   I want to learn this stuff and I feel that I can do it, although I might need a little guidance.   I don't expect anyone to do my homework for me, just maybe double check my design before I take it to the city, that's what I'm hoping for.

[Spork Schivago]

Also, that transformer lists the input as 240,480VAC.   It also lists it as single phase.   240x480 on the primary, 120x240 on the secondary.   With it being one phase, wouldn't that put us in the same predicament that we're in now?   Or am I misunderstanding something here?

That is a single-phase transformer.  There is only one core.  Than makes it single phase.  All the input (primary) and output ( secondary) wires are isolated from ground so that you can connect it whichever way you need.  You can connect the primary to anything from 216 to 504 volts.  And you can wire the secondary for either 120V or 240V.

So I'd connect the primary lines to H1-H3 and H2-H4, then I'd connect the secondary lines to X1 - X4?

No, you will blow up the transformer and burn down your house if you do that.

You need a straight-across, 1:1 transformer from your 240V "split-phase" source to a 240V, ground-referenced single-phase output.

The table shows that for 240V input, one side goes to H1 and H7 connected together, and the other side goes to H10 and H4 connected together
And the table shows the for 240V output it comes from X1 and X4, with X2 and X3 connected together.

If you connect X1 to ground, then X1 becomes "Neutral" and X4 is the source of your ground-referenced 240V SINGLE PHASE.

Please note that I am NOT a professional electrician, and I am not a licensed practicing engineer.  You should seek competent advice from a professional licensed in your jurisdiction.  High-power engineering advice, like legal advice is never completely reliable from a stranger on the internet.  Just common sense.

Huh, the way you've been talking, I thought you were a professional electrician.   Regardless of whether you are or not, isn't this the whole reason I'm required to have a permit?   They have a professional electrician go over my diagram to make sure it's sound and not going to blow up the transformer or kill someone?   I am going to study the wiring diagram again and re-read what you wrote, to see if I can understand it more clearly.   I'd connect H1 and H7 together, and then run 120VAC to H1 and H7.   I'd connect H10 and H4 together, than run the other hot from the double pole to H10 and H4.   We have 200-amp coming in.   I told my wife, we might need to upgrade that to 400-amp.   She wasn't happy about that at all, seeing how we just paid to go from 100-amp service to 200-amp service.

[Monkeh]

Forget about the transformer.

Get some P9S12As instead.

[Spork Schivago]

I cannot use the P9S13A's.   That's 208VAC outlets.   I need 220VAC+.

The HPE P9S13A shows on page 8 of the HPE G2 Switched Power Distribution Units.PDF as having input of 1-ph 200-240V 24 amps with L6-30P plug on the cord.  It has the same footprint, the same outputs as the P9S16A.  The two are probably exactly the same except for input cable, plug and internal breakers. 
There is zero chance that the P9S13A can magically reduce the input voltage of 240 down to 208 volts.
The HPE website is anything but user friendly and seems like it is a product of marketing with almost total disregard for engineering; in other words, business as usual.  The places that state it is 200-208V are most likely cut and paste errors by the person that made the document.

I gotcha.   That was the only reason we originally ruled out two P9S13A's.   The document, as you referred to, on page 8, shows that it'd work, but one their sales page, it shows it wouldn't.   When talking to their sales, it seems they tend to reference that sales page, rather than the technical document.

I think the transformer is cheaper than two P9S13A's though, and I'd like to learn how these transformers work, how to wire them properly, etc.   It's a new experience for me, so I think we're going to go that route.

[Richard Crowley]

Are all your loads (computers) set for 230V? 
Those PDU gadgets don't change the voltage.
If you put 230V in, the provide 230V out.

[Spork Schivago]

With
P9S16A
HPE G2 Swtd 7.3kVA/60309 2U INTL PDU

In the USA in a house, I see one of three things happing.

1. You burn your house down and insurance will not cover loss.
2. You get someone hurt, probably criminal charges.
3. You destroy some equipment.

HP lists four major categories of models

220-240V Input, Single Phase, International
Not a standard in USA.

200-208V Input, Single Phase, North America/Japan
Is using one phase of a three phase power source. Only industrial not in a house.

100-240V Input, Single Phase, Worldwide

This only matches the 110-120 used in USA.
And
HP makes a model for this
100-120V Input, Single Phase, North America/Japan

USA's 220-240Volt house standard does not match any of above.
As has been stated many times it is split phase with two hots and a common or center tap.

So the outlets of P9S16A with a transformer will still be non-standard in the USA and that will probably get someone/thing hurt!

C

Why would that transformer Mr. Crowley linked to get someone hurt?   When you say non-standard, do you mean not-common, or it violates some standard somewheres?   When we were looking into three-phase, an alternative the electrician gave us was a transformer, although there where some down-sides, if I remember correctly (which I might not remember correctly) about using it, compared to direct three-phase.   I think he said something about it wouldn't be "true" 3-phase.   It would look like it, but wouldn't be as clean or something.    I took it (just as a comparison) as comparing a digital oscilloscope to an analog.   The analog will provide a true sine wave, but a digital will try to emulate it, buy drawing lots of little tiny squares (or whatever) to make it appear as a sine wave.

[Bratster]

The correct thing to do in the situation is to get the correct power distribution unit. It is unfortunate that you already have one that will not work easily.

If you absolutely have to use the one that you already have, and don't mind the possibility that it may never be fully compliant since it is not intended for the u.s...

Then you have to use the Transformer that is already been picked out by other people or something along those lines.

And you would wire it for 240 volts input, split-phase, from your circuit breaker panel. And then the output would get wire for 240v with the secondary side wired as a separately derived power source. One side of the Transformer secondary would be grounded and become your neutral the other side would be 240 volts.


Also the loads you're plugging into this, they do accept 240 volts right? Stupid question but just making sure.

Edit: other people already posted some of what I said while I was typing, sorry about that.

Sent from my Moto x4 using Tapatalk

[Richard Crowley]

Because of the money we have invested in equipment at this point in time, I do not feel comfortable discussing publically what the loads are, however, if you would like to know, I would more than happy to PM you. 

We don't care what they are. I was just asking what is the nameplate rating of the power consumption.  You can't identify what kind of car I drive if I tell you that the engine has 230 horsepower.

I'm still a bit confused about the phases here.   I understand how the 240VAC works in the US.   120VAC to neutral, 120VAC to neutral, 240VAC going from hot to hot.    I understand the breaker panel, I've studied it and the various names.   I know the ground buss-bar and neutral buss-bar's are connected with a jumper wire usually.   I know there's a hot buss bar where every other connector runs off the other incoming main line.


For example, the first single pole breaker, #1, runs off the first of the two incoming main 120VAC hot lines.   #3 (directly below it), runs off the second of the two incoming main 120VAC lines.   #5 runs off the first, etc.   This is why when we install double-pole breakers, we can get 240VAC from hot to hot, instead of just 120VAC.

If I were to somehow attempt to create my own 240VAC source by using single pole breakers #1 and #2, it shouldn't provide 240VAC, from my understanding (I've never attempted), but should provide 120VAC, because they're on the same "phase".

So, if what we have is called 1-phase, but not by electrical engineers, what is it called by electrical engineers, and what is split-phase?    I thought split phase was the whole 120VAC - Neutral (or ground) - 120VAC, giving us 240VAC....

I thought split-phase was where the hot was split between two wires, each 180 degrees out of phase.   When one was at 120VAC, the other was at -120VAC, giving us 240VAC.

The standard her in North America (or at least the USA) is that the power utility delivers 240V to your house (and my house)  But it is center-tapped, and the center-tap is grounded.  So if you take either side to ground/neutral, it will be 115V.  And the only way to get 240V is to connect from one side over to the other side, but then BOTH sides will be 120V above ground because the center-tap (aka. "ground", or "protective earth" or "neutral") is grounded.

As I said before consumer, domestic appliances that run on 240V are designed with the assumption that both sides of the power line are at 120V above ground. They typically have double-pole switches, breakers, etc.  Just as a 240V branch circuit uses a DOUBLE pole breaker. 

But those HPE PDU things were designed to operate on single-phase sources.  That means that the "Neutral" side is essentially zero volts.  You don't have 240V GROUND REFERENCED coming into your house.  You have only two out-of phase 120V ground-referenced circuits.  So the only way you can get 240V is to connect from one "hot" side over to the other "hot" side.  Electricians call these "phases" but they are not.

Also, in the first post, I believe, I did mention that it was a PDU for my server rack, because I realize even the name PDU could mean multiple things, and it's important that you guys knew I was referring to a power distribution unit for a rack, holding expensive computer equipment.

You can go back and read it for yourself.  You did not identify that it was a PDU, and you did not identify that it was going into a rack, and you did not mention that it will be powering computers.  You only revealed that it was "a device".

Finally, because we are running a business, have a daughter, living in the city, etc, we will always follow the law, and get the proper permit, after drawing up our design, and have it inspected.   In the country, where we used to live, when I ran the 240VAC to my BGA rework station, we had tried, but the city inspector didn't really care about the country, which we thought was odd.   Technically, we were living in the Town of Country, not the City, but they said generally, in the country, you just wire it up or hire someone to wire it up.   They wouldn't actually come up to inspect my work.   I thought that was horrible and should have been reported.

That is good.  You can try drawing up the diagram yourself and submitting it to your jurisdiction (city or county, etc.)  But some jurisdictions won't accept submissions unless they come from a licenced architect (or whatever).  If you can befriend someone in the planning/permits office, they could help you create something they will accept.

I still want to wire the transformer myself.   I want to learn this stuff and I feel that I can do it, although I might need a little guidance.   I don't expect anyone to do my homework for me, just maybe double check my design before I take it to the city, that's what I'm hoping for.

Read the transformer specs very carefully and double-check how you are connecting.  Something that high-power really can burn down your house if you don't get it right.  You are operating in dangerous territory for an amateur.

Huh, the way you've been talking, I thought you were a professional electrician.   Regardless of whether you are or not, isn't this the whole reason I'm required to have a permit?   They have a professional electrician go over my diagram to make sure it's sound and not going to blow up the transformer or kill someone?

Yes, if it is officially approved by the jurisdiction, you have reasonable assurance that it is legal.  But there are many details where you could go wrong that are not on the plans or reviewed by the authorities.

I am going to study the wiring diagram again and re-read what you wrote, to see if I can understand it more clearly.   I'd connect H1 and H7 together, and then run 120VAC to H1 and H7.   I'd connect H10 and H4 together, than run the other hot from the double pole to H10 and H4.   We have 200-amp coming in.   I told my wife, we might need to upgrade that to 400-amp.   She wasn't happy about that at all, seeing how we just paid to go from 100-amp service to 200-amp service.

NO!  Nobody mentioned 120VAC anywhere.  The transformer will take the split-phase 240V from your domestic service and turn it into 240V "single-phase", ground-referenced which is what the HPE PDU is designed for.  If you try to connect that transformer to a 120V circuit, you will be lucky if only the breaker blows.

[IanB]

They have a professional electrician go over my diagram to make sure it's sound and not going to blow up the transformer or kill someone?

Just for clarity, there's a difference between an electrician and an engineer (a P.E.).

An electrician will provide and/or inspect an installation to make sure it complies with the applicable code. You may get some variation between electricians about how to interpret the code in some areas of detail, but primarily electricians follow their training and make sure what is done matches what the code says should be done.

On the other hand, the code itself is written by P.E.'s with relevant professional experience in wiring and power distribution systems. If you hire a professional engineer they can potentially design a system that has variances from the code, and can justify by calculation why those variances are safe, and can put their professional stamp on that design to certify it. Needless to say, it will cost a lot more to hire a P.E. than to hire an electrician. But in special circumstances it may be worth it.

(This is just in general--I'm not saying you need to hire a P.E.)

[bob225]

I would check your lease or land title and the zoning laws in you area, the last thing you need is $K in fines, or swat busting your door down because they think you have a grow (high power usage)


2018 Honey I blew up the house

[Richard Crowley]

Why would that transformer Mr. Crowley linked to get someone hurt? 

Easy.  By improper installation, incorrect connection, etc.  It is unfortunate when somebody powers a little 5V board from 12V and turns it into toast.  But is is a whole different ballgame when you are talking about thousands of watts of power that could kill your whole family AND burn down your house.

When you say non-standard, do you mean not-common, or it violates some standard somewheres?

Didn't you answer that yourself when you said that the electrician would not connect to the IEC Euro-connector?  Of course, maybe that was just someone who does domestic wiring in private homes.  Not surprising that they would shy away from an unfamiliar connector.  But if you were talking to an electrical contractor that does big commercial and industrial projects, they may have had a very different response.

When we were looking into three-phase, an alternative the electrician gave us was a transformer, although there where some down-sides, if I remember correctly (which I might not remember correctly) about using it, compared to direct three-phase.   I think he said something about it wouldn't be "true" 3-phase.   It would look like it, but wouldn't be as clean or something.    I took it (just as a comparison) as comparing a digital oscilloscope to an analog.   The analog will provide a true sine wave, but a digital will try to emulate it, buy drawing lots of little tiny squares (or whatever) to make it appear as a sine wave.

Yes, people who buy big industrial machines (lathes, milling machines, etc.) to put in their garage are faced with the problem that big motors operate on 3-phase power which is very rare here in North America in private homes.  So there are all sorts of gadgets from rotary converters (a single-phase motor driving a 3-phase alternator), or electronic circuits that create 3-phase, to dodgy resonant contraptions that put out pseudo-3-phase.

But you do not need 3-phase.  You are having enough problems just getting 240V single-phase.  And the PDU you selected isn't suitable for a 3-phase source any more than it is suitable for 240V split-phase.

[Spork Schivago]

Are all your loads (computers) set for 230V? 
Those PDU gadgets don't change the voltage.
If you put 230V in, the provide 230V out.

Yes.   For the servers, the PSUs we needed are only provided in 240V, because of how large they are.   For the other equipment, we have the option of running 120VAC or 240VAC.    For the PSUs, the lowest I think was 220VAC, not 208VAC or anything.

The ones for the servers run optimal when the hardware is drawing 80% of what they're rated for.   Each server has two 1400 watt PSUs in them.   It's probably obvious that we have a switch, so I see no harm in sharing that.   The switch has two 500 watt PSUs, currently running at 120VAC.   The second is for redundancy.    With the various hardware, there's proper ways to make sure they're cooled adequately.   For example, with our servers, we needed to purchase the high performance fan kits and heat sinks, because of how much more powerful the CPUs where compared to the ones that came with them.   The idea is to switch all the equipment that is capable of running off 120VAC or 240VAC over to 240VAC.

I can PM you a list of the other equipment that draws a good bit of current, if you're interested.   I just don't want to share it publicly on the list.   We have a lot of thieves around here.   I had some acquaintances that weren't the best type of crowd.   We are dealing with what we consider confidential / sensitive information, and with some of the contracts we have, we need to take certain security precautions.   We have x amount of time to implement the SOPs and then they come to the house and perform an audit.   It's our responsibility to keep the information secure, the network secure, etc.   We can't even have anyone down in the basement unless they sign an NDA.

For the local electric company, we had to have them install something outside the house, so they didn't have to go down in the basement to read the meter.

[IanB]

As for the cooling, eventually we will get central air, but right now, being in the basement, we've kinda got lucky.   Throughout the year, it seems to maintain an almost stable temperature and is cool.

Hopefully you realize that will only be true as long as the basement is not full of computer equipment?

At work our server rooms always have to have big powerful aircon units in them. If for any reason the aircon unit fails the temperature in the room skyrockets, alarms go off, and then all the equipment shuts down due to overheating.

What you need to do, if you haven't already done it, is to add up the power consumption of all the equipment in the basement (seems like it could be around 7 kW based on the size of the PDU?), and then determine how you are going to remove 7 kW of heating from the room. You can imagine that if you put a 7 kW electric heater in your basement it is not likely to maintain a stable, cool temperature...

[Spork Schivago]

...

I am going to study the wiring diagram again and re-read what you wrote, to see if I can understand it more clearly.   I'd connect H1 and H7 together, and then run 120VAC to H1 and H7.   I'd connect H10 and H4 together, than run the other hot from the double pole to H10 and H4.   We have 200-amp coming in.   I told my wife, we might need to upgrade that to 400-amp.   She wasn't happy about that at all, seeing how we just paid to go from 100-amp service to 200-amp service.

NO!  Nobody mentioned 120VAC anywhere.  The transformer will take the split-phase 240V from your domestic service and turn it into 240V "single-phase", ground-referenced which is what the HPE PDU is designed for.  If you try to connect that transformer to a 120V circuit, you will be lucky if only the breaker blows.

It was the 2nd and 3rd post I made where I said it was a PDU going into a rack and gave the model number, you are correct.   I actually tried uploading pics of the plug and in that post, I believe I actually wrote a statement saying that because PDU can mean multiple things, blah, blah, blah, this was for a rack and would run computer equipment.   But for some reason, that post never made it threw.

So, I run both "phases" or "mains" into H1 and H7, after tying them together?    and then neutral into H10 and H4 together?    My wife just got home and I'm the only one who watches my daughter while she's at work, so I can't do much with the business until she gets home.   I can post a list of exactly what loads we have (or at least, what power supplies we have).

I think C said there's no way to safely do this though.   So if the transformer is wired correctly, I'm a bit confused as to why some say it will work, some say it won't.   We have also sent a message to our licensed electrician, but that's a pain now.   We were offered some contracts, they're a one time thing.   It's not what we want to do with our business, but we took them.   We know someone who knows someone and a company or two outsourced to us.   Having someone down there, even to wire it up means we gotta get it approved by at least one of the companies, if not both, have the electrician sign an NDA, etc.   It becomes a real pain.   In my jurisdiction, I can provide the sketch myself.   We did that when we wired the low-voltage wires for our daughter's room, so we're familiar with the process there.    Here, we can run ethernet, for example, between two floor joists that connect to the cold-air return, but only if we use plenum grade ethernet.  We don't actually run it down the ductwork, we run it outside of the duct-work.   But if it wasn't plenum grade, we wouldn't be able to do that, unless we used conduit or something along those lines.

[Spork Schivago]

Why would that transformer Mr. Crowley linked to get someone hurt? 

Easy.  By improper installation, incorrect connection, etc.  It is unfortunate when somebody powers a little 5V board from 12V and turns it into toast.  But is is a whole different ballgame when you are talking about thousands of watts of power that could kill your whole family AND burn down your house.

Yes, I understand that, but _if_ it's wired correctly, the way C was responding, it sounded like it was just wrong and wouldn't work.   Even DC can be dangerous and kill you.    I try to treat all electricity as the same.   I don't have special rules just for low-voltage sources.   I try to practice safe standards everywhere, even if there isn't necessarily a threat or chance for personal injury.   That way, it becomes a bit of muscle memory.

When you say non-standard, do you mean not-common, or it violates some standard somewheres?

Didn't you answer that yourself when you said that the electrician would not connect to the IEC Euro-connector?  Of course, maybe that was just someone who does domestic wiring in private homes.  Not surprising that they would shy away from an unfamiliar connector.  But if you were talking to an electrical contractor that does big commercial and industrial projects, they may have had a very different response.

When we were looking into three-phase, an alternative the electrician gave us was a transformer, although there where some down-sides, if I remember correctly (which I might not remember correctly) about using it, compared to direct three-phase.   I think he said something about it wouldn't be "true" 3-phase.   It would look like it, but wouldn't be as clean or something.    I took it (just as a comparison) as comparing a digital oscilloscope to an analog.   The analog will provide a true sine wave, but a digital will try to emulate it, buy drawing lots of little tiny squares (or whatever) to make it appear as a sine wave.

Yes, people who buy big industrial machines (lathes, milling machines, etc.) to put in their garage are faced with the problem that big motors operate on 3-phase power which is very rare here in North America in private homes.  So there are all sorts of gadgets from rotary converters (a single-phase motor driving a 3-phase alternator), or electronic circuits that create 3-phase, to dodgy resonant contraptions that put out pseudo-3-phase.

But you do not need 3-phase.  You are having enough problems just getting 240V single-phase.  And the PDU you selected isn't suitable for a 3-phase source any more than it is suitable for 240V split-phase.

Yes, I know I don't need three-phase.   We made the choice for 1-phase because of costs.   I was using that just as an example.  I was thinking maybe what C meant was with the transformer, it wouldn't be considered true 1-phase 240VAC.    It'd be pseudo-1-phase 240VAC and would possibly not be safe, for example, with the devices that are US made with the 120VAC / 240VAC switch on the PSUs, or with the actual PDU itself.   Do you follow what I was saying now?

Thanks.

[Spork Schivago]

As for the cooling, eventually we will get central air, but right now, being in the basement, we've kinda got lucky.   Throughout the year, it seems to maintain an almost stable temperature and is cool.

Hopefully you realize that will only be true as long as the basement is not full of computer equipment?

At work our server rooms always have to have big powerful aircon units in them. If for any reason the aircon unit fails the temperature in the room skyrockets, alarms go off, and then all the equipment shuts down due to overheating.

What you need to do, if you haven't already done it, is to add up the power consumption of all the equipment in the basement (seems like it could be around 7 kW based on the size of the PDU?), and then determine how you are going to remove 7 kW of heating from the room. You can imagine that if you put a 7 kW electric heater in your basement it is not likely to maintain a stable, cool temperature...

Yes, we know that it will heat up quickly when we start powering the equipment up, and have plans for a central air conditioning unit.   Until then, we have A) a portable unit we can use B) a wall unit we can use.   They're not the best options, but they can work until we have the central AC installed.

We did add up all the equipment and currently got around 5kW, but that was excluding the upgrades that we are planning on purchasing.   With the extra's, yes, we'll be around 7 kW, then during phase three, we'll be even higher, and will need another PDU.    At that point, hopefully we have enough income to get a dedicated panel just for the business though.

Removing 7 kW of heating is something I hadn't put too much thought into.   I didn't think of it like that, so I like that idea.   We remove the condensation from the room, which makes it feel cooler and doesn't provide danger to the equipment (condensation tends to rust equipment, might even short parts out, etc).    We do need to have the outside of our house tore up and properly sealed, but that's later on.

We have special sensors to monitor the temperature of the equipment in the rack, and it's designed to send us various messages, set off alarms, if certain conditions are met.    One of them includes heat.   If heat gets too high, we get cell phone messages, and there's a program written that should set off one of the alarm systems down there.

At my old work, in the server room, they had residential ACs running and just dumping the water between the cement walls, which was a horrible idea, but it saved them money.   Eventually, this caused a lot of problems for the company with things like mold.   So in the end, it costed them more money than they saved.

We also plan on purchasing a whole-home generator, that will be installed by a professional, with an automatic transfer switch, and we still need to figure out the UPS setup, where it can power the equipment long enough for the whole-home generator to kick on.   That's one of the biggest reasons we took on the first contract.   It's getting close to being finished and pays us a good amount of money that should allow us to finish purchasing those things I just mentioned.

[Spork Schivago]

Right now, we're currently at 6,360 watts, assuming full load on all devices.   That's what all the name plates, added up, come to.   Keep in mind, most systems shouldn't be running at exactly what the power supply is rated for.   They should be running at around 80% or so of what the power supplies are rated for.

Almost all the devices don't have a switch for 240VAC, but they say 115 to 230VAC for input.   And reading the technical manuals, they auto-detect and expect single-phase.

There are some other devices that we're using, but they're not rack-mountable, so we did not include them, like the BGA rework station that claims it draws 4,800 watts.   It's using Elstien heating elements for the pre-heater part, but it's a cheap Scotle unit.   Just something we bought a few years back to get us up and running.   They're not powered by this PDU, but are connected to the same panel as the PDU's transformer will be connected to.

I think I will go for the 10kVA one.   

[james_s]

Remind me what this is all for?

IMO by the time you get to several kW of computer gear in the basement, it's time to start looking for a proper data center.