Electronics > Beginners

How to wire up a 240VAC receptacle

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IanB:

--- Quote from: Spork Schivago on May 16, 2018, 04:38:46 pm ---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 ---

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:

--- Quote from: Spork Schivago on May 16, 2018, 05:16:04 pm ---Why would that transformer Mr. Crowley linked to get someone hurt? 
--- End quote ---
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.


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


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

--- Quote from: Richard Crowley on May 16, 2018, 05:15:12 pm ---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.

--- End quote ---

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:

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

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...

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