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Single Phase Problem

06/18/2017 8:23 AM

i was told a single phase is a two wire system, so to get a 220 volts i need a three wire system. but im encountering a problem where im living in south america,a country call guyana not ghana. the power company came and provide electricity to my home,but the only ran two wire,one neutral and one live..but when the leave i decided to take my multimeter and take a reading, and its saying 220volts instead of 120 volts, why is that happen? dont the power company need two live or two hot wire and the ground to produce 220v

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#1

Re: single phase problem

06/18/2017 8:35 AM
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#2
In reply to #1

Re: single phase problem

06/18/2017 10:17 AM

it has both 120 and 240v. but my problem is how can they provide 240v with one hot wire and one ground?

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#3
In reply to #2

Re: single phase problem

06/18/2017 10:37 AM

What has both 120 and 240v?

If you need 120 volts, you will have to get one or more 240v/120v transformers, with enough power rating to handle your loads (appliances).

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#4
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Re: single phase problem

06/18/2017 11:13 AM

It all depends on how the transformers are set up....you start with a very high voltage coming from the generation facility and it is gradually stepped down to lower voltages at the points of use....

Using a transformer you can raise or lower the voltage to what is required....generally each country makes that determination of what will be the standard voltage supplied to houses, it is usually an accepted standard that appliances require....a 120v to another 120v = 240v single phase(2 wires)....240v to neutral = 240v single phase(2 wires)...

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#5
In reply to #4

Re: single phase problem

06/18/2017 12:36 PM

That looks a bit weird; between each 240v pair, it gives 480v. (Not impossible, but weird.)

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#6
In reply to #5

Re: single phase problem

06/18/2017 7:43 PM

I'm guessing that each customer only gets 240v and the neutral wire. The neighbor next door might get the other phase, so the potential between the two "hots" might be 480vac.

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#7
In reply to #4

Re: single phase problem

06/18/2017 10:37 PM

That's a diagram of a SWER (Single Wire Earth Return) system, rarely found except in very remote regions. The exact implementation varies by country and region; the one in that illustration supplies 230VL-N for normal loads, or 460VL-L for large single phase loads such as pump motors.

I do question how technically astute the author is, particularly the note that says "Separate High Voltage and Low Voltage Earths" since "earth is earth", and all current returns to the source via the same earth.

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#10
In reply to #4

Re: single phase problem

06/19/2017 4:32 PM

In other words, when supplying 240 VAC single phase, through one hot and one neutral, the neutral to ground short will kill you as quickly as hot to ground.

Sounds like a moron came up with that system, sorry, but are they competing in this year's Darwin Awards for best mass hazard scheme?

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#8

Re: Single Phase Problem

06/18/2017 11:13 PM

"i was told a single phase is a two wire system, so to get a 220 volts i need a three wire system...", You are confusing the number of wires with the voltage between them. Depending upon how the transformer is constructed, you can get either 120V or 240V (but not both simultaneously) across two wires (one hot, one neutral), or both 120/240V across three wires (two hot, one neutral) where the two hot wires are 240V apart but only 120V from one hot to neutral.

Unfortunately in Guyana, you do not have a choice of supply voltage, that depends upon which county/region you live in, so moving around may render your current appliances unusable because "... GPL supplies all its domestic customers with voltage ranging from 110 to 220 Volts depending on the area. The voltage distribution system of GPL is quite unique since it delivers both 50 and 60 cycle power..."

Here's their website. Contact a local electrician familiar with your particular situation.

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#11
In reply to #8

Re: Single Phase Problem

06/19/2017 4:34 PM

Makes me right proud to be an American, where at least I won't fry grabbing white, usually.

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#9

Re: Single Phase Problem

06/19/2017 5:15 AM
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#12

Re: Single Phase Problem

06/19/2017 5:11 PM

As it was explained to me once when I was helping a friend move there, GPL does not distribute 50Hz power, but there are still pockets of autonomous generation in some regions where GPL doesn't reach yet, and many of them supply whatever power comes from the generators they bought the day they needed power, meaning some will put out 380V 50Hz 3 phase 4 wire power, so the single phase feed from that is 220V Line to Neutral.

There is a movement afoot for them to convert all regions over to GPLs standard 60Hz power, because they made a major investment in Hydro power from a big waterfall, and they want the revenue from everyone to help defray the costs. That system is all 60Hz and will be set up similar to other countries in the area, basically the US system of 3 phase distribution to industrial and large commercial customers, and 110/220 "split phase" 3 wire (L-N-L) for residential customers.

So if you (fitzzchisholm19) have 220V L to N, that means you are in one of those still autonomous power areas supplied by privately owned European diesel generators and will be 50Hz. You will not be able to use 110V appliances unless you go buy your own transformers (or "travel converters"). Be aware though that old motorized electric clocks will not keep time and other 110V appliances with AC motors will run slower.

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#13

Re: Single Phase Problem

06/29/2017 10:38 PM

"dont the power company need two live or two hot wire and the ground to produce 220v"

In the above statement this is true if the utility use a 3 wire system (in case of delta connected) each wire gives 120 V, Yes single phase installations requires two wires to have at least a suitable voltage level which is also country dependent (in your case 220V).

What you also need to know aside from just the "single phase" is how supply lines is configured (wiring, configuration delta or wye) For the above example if a utility uses a delta configuration two lanes A&B will have a voltage level of 120 V each, by providing customer with both lanes A & B they will have a 220 V ready supply to power up appliances.

In case of a 4 wire configuration (Wye connection, 4th wire is for the neutral maybe grounded or ungrounded if 5 wire) each lanes A-B & C are rated at 220 V the neutral wire will act as a return part therefore completing the circuit that is why in your case when you measure your conventional outlet the multimeter gives 220V not 120V.

I hope this helps

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