three breakers share one neutral and one grouding wires

[dpb]

On 11/28/2014 5:19 PM, yyy378 wrote: ...

The attached indicates Myanmar follows IEC and has 230V/50Hz distribution for low-voltage (household) use.

Code in US isn't government-controlled, either, the NEC is written/maintained/underwritten by a private membership non-profit corporation. Local governmental regulations may require use of these Codes but that's not the same thing as the government itself actually being the regulator. Hence, I suspect the response to the question asked was correct; if you're located in a population center of any size I'd be quite surprised if there isn't a regulation somewhere that doesn't reference IEC or the like.

Now, that building codes and the like may not be enforced or very laxly enforced wouldn't surprise me a bit...there are areas in the US where that is also true.

As others have said, I suspect the only way to get any kind of resolution whatsoever on your queries here will be for you to take and post pictures on one of the hosting sites that show the subject pieces/parts and areas of concern/question. Simply trying to describe it with the unfamiliarity from both sides isn't going to get anywhere useful as can be seen from the meandering thread...

[Seymore4Head]

230V single phase would be double pole breakers, wouldn't it? Do they even use a neutral?

[dpb]

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This makes zero sense...there is no such thing as "wiring single-phase in a 3-phase way". It's either single or three phase.

Can you make a sketch of what this arrangement is or are you making assumptions as to what wires go where and where return neutrals/grounds may be just by looking at one end?

[dpb]

Yeah, 'cepting up way early he's insisted there are only two service leads to the panel so it can't be three phase.

I'd also suspect that 3- and single-phase don't exist side-by-side routinely even in Myanmar in residential dwellings unless they're sizable apartment complexes--it isn't logical they'd go to the expense.

It's frustrating that the OP doesn't just follow-up with a picture or two on one of the hosting sites...it would be interesting to see the actual setup if nothing else.

[John G]

you must live in the splendid isolation of the USA. 3 phase is very common in residentials in the real world. :-?

[dpb]

On 11/30/2014 4:21 PM, John G wrote: ...

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Perhaps; not a routine habit in opening service closets when visiting... :)

[TimR]

I was rather surprised to see electric boxes exposed in hallways and basements in Germany rather than in closets, and to be covered in plexiglass rather than steel. And yes, you could see 3 phase connections clearly that way.

[dpb]

But were those single-residence dwellings or multi? I've seen it in England as well but was always in hotels and/or apartment complexes, not single residences. It's the latter I've never poked around in when doing the B&B thingie; figure that's a little "over the top" for an in-house guest even if it is a routine of the household to host... :)

I've not been anywhere in Asia other than one trip to S Korea for a business purpose following a nuclear power plant man-replacement robotic system delivery for which had done most of the software. That was a very uncomfortable trip in the mid-80s when made it and was glad to "get the heck out of Dodge" when it was over. Outside the plant I saw virtually nothing and we were escorted everywhere...think China wouldn't have been any less restricting at that point.

Anyway, the general rules I've always figured were more-or-less universal simply based on the equipment and end use would be something like the following --

"2. Residential Service at 120/208 Volts:

In areas where the secondary distribution system is 208Y Volts, three phase, 4 wire (grounded neutral), residential buildings with one or two dwelling units are served through a single phase, 3 wire, 120/208 Volt common service.

Residential buildings with three or more dwelling units are served through a three phase, 4 wire, common service and the individual single phase, 3 wire, 120/208 Volt sub-services to the individual dwelling units shall be balanced as nearly as possible on the three phases.

All services, other than residential, are served through three phase, 4 wire services except small establishments with limited loads requiring a service of 100 Ampere or less capacity. They may be served through a single phase, 3 wire service."

OP in this thread never indicated despite being asked about what the facility itself was other than clearly was his residence. Sorry he seems to have disappeared w/o ever getting to the bottom of it.

[John G]

Yes the OP eventually said there were only 2 wires at the building entry so the whole thread is confused by that. As for Distribution.

you must live in the splendid isolation of the USA. 3 phase is very common in residentials in the real world. :-?

In the 50 hertz world-- A lot (I cant say all) distribution is 3 phase

230/400 volts from a big transformer (the one at my front gate is 400 KVA) that serves a number of single residences, most of which get 3 phase because they have 3 phase air conditioners and this has been the practice for many many years. Of course the use of air cons has risen dramatically as the standard of living has risen. 120/240 single phase and 120/208 three phase and small pole pigs is a system limited to the 60 hertz world and certainly not universal.

Too often statements are made as Absolute Facts in various news groups when really they are only the very limited experience of the poster :-Z

-Z

[dpb]

As said, nothing was said as "absolute" simply an impression from what I've seen in what overseas I've been at...and while that's a little limited, my time in Germany and England didn't run across any 3P in the single-family housing with which I came into contact -- and that was on the order of a couple dozen I'd guess w/o a firm count. Of course, I'm not sure there was a single one of them that did have A/C; don't recall one...

While particular voltages/frequencies are US, still distribution is 3P until the transformer...and again, it's been mostly 25 yr ago or so since was there a lot and time in Germany was back in the 70s when employer here was trying to start a series of European co-ventures. Babcock-Brown/Boveri in German, Babcock-Atlantique in France, ... All were rather short-lived with the demise of nukes in the US there was no piggy bankroll any longer.

[trader_4]

Another angle on 3 phase showing up in typical houses in other countries would be if it is done, what's the purpose? I see extra cost, but I don;t see a benefit. The loads are all single phase, just like they are here, aren't they?

[TimR]

I didn't understand that either. My house in Germany had 3P, but as far as I could tell all the loads were 1P. There must be an advantage, maybe somebody can explain it.

[John G]

No The general household loads are of course only single phase. In the past some Electric stoves were spread over 2 phases but with increased capacity in the whole system I think that practice has ceased

Many Aircnditioners have 3 phase compressors and single phase 240volt control and fan circuitry.

In recent times there has been a growth in "INVERTOR" air cons and I guess they are only single phase as they are supposed to be more economical.

I have no idea why we have 3phase 400 volt compressors and the USA manages with just single phse 240volt compressors but that is a system designers area not a simple electric technicians job :-?