Electronics > Beginners

How to wire up a 240VAC receptacle

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Spork Schivago:

--- Quote from: Gregg on May 16, 2018, 02:18:00 am ---
--- Quote from: Spork Schivago on May 16, 2018, 12:02:20 am ---I cannot use the P9S13A's.   That's 208VAC outlets.   I need 220VAC+.

--- End quote ---
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. :-//

--- End quote ---

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:

--- Quote from: C on May 16, 2018, 02:32:01 am ---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

--- End quote ---

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:

--- Quote from: Spork Schivago on May 16, 2018, 04:33:42 pm ---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. 
--- End quote ---
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.


--- Quote ---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.
--- End quote ---

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.


--- Quote ---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.
--- End quote ---
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".


--- Quote ---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.
--- End quote ---
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.


--- Quote ---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.
--- End quote ---
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.


--- Quote ---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?
--- End quote ---
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.


--- Quote ---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.
--- End quote ---
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.

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