3 Phase Power

Gordon_R

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Jul 5, 2009
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#2
The only appliance that is wired for 3-phase power in a normal household is an electric stove. You would never (seriously) run that off a generator, so everything else would work fine.

You would also never plug a a generator directly into the distribution board, so when its done properly, a qualified electrician would know what to do...
 

savage

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Aug 11, 2003
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#4
Well, phases should be balanced. So a generator just one one phase (and putting your load only on one phase) means your phases won't be balanced anymore. Obviously depends on the load...
 

greggpb

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#5
Well, phases should be balanced. So a generator just one one phase (and putting your load only on one phase) means your phases won't be balanced anymore. Obviously depends on the load...
Thanks so much guys, building our house in phases so we went 3 phases but think we are only using one at the moment, so as a quick fix I should be able to get a 1 phase generator.
 

greggpb

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#6
The only appliance that is wired for 3-phase power in a normal household is an electric stove. You would never (seriously) run that off a generator, so everything else would work fine.

You would also never plug a a generator directly into the distribution board, so when its done properly, a qualified electrician would know what to do...
THanks mate, thankfully GAs Stove
 

The_Traveller

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#7
Thanks so much guys, building our house in phases so we went 3 phases but think we are only using one at the moment, so as a quick fix I should be able to get a 1 phase generator.
If you got a 3-phase supply, that means you are using all 3 phases. What you need to do is get the council to change your 3 phase to a single phase.
 

mmacleod

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#8
Only stick with three phase if you actually have a good reason to do so, otherwise you will keep having extra costs for it at every turn when it is unnecessary.
 

cavedog

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#12
If your house is supplied by 3 phase you can still use a single phase generator by simply bridging the 3 live wires. Am I correct at saying this?

Since everything in the house is single phase even the poolpump this means that if you get 3 phase supply from the municipality or eskom they simply wired the house to split the load over the 3 live wires. It does not mean your appliances are suddenly 3 phase.

Also I stand to be corrected but if you have 3 phase power you must be on postpaid billing and receive a bill where they measured the consumption on all 3 live wires?

Also I don't think it is very important to split the load equally across the phases unless you got sensitive 3 phase ewuipment running. I stand to be correct because I'm no expert.
 

Gordon_R

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#14
Don't see why a house would need 3 phase at all tbh.
There is a physical limit to how much current you can draw through a single phase power supply (typically 60-80 amps). A large residence with electric stove, geyser, tumble drier, and room heaters would easily exceed this limit at times.

BTW: Tripping the mains power can be a great inconvenience (especially if you have to phone the council to get re-connected!?)
 

greg_SA

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May 24, 2005
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#15
I have 3 phase at home. I'm on prepaid. The meter measures the power of all the phases independently. AFAIK, the load doesn't have to be balanced - all my loads are single phase. I could run everything off one phase if I wanted.

The advantage of 3 phase, is that you have more power available - 3 x 60 A = ~ 40kVA., and you can run 3 phase equipment. If you have lots of aircons, pool heater, jacuzzi, etc, then it is handy.

You can't bridge/join the phases together!
 

savage

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#16
I have 3 phase at home. I'm on prepaid. The meter measures the power of all the phases independently. AFAIK, the load doesn't have to be balanced - all my loads are single phase. I could run everything off one phase if I wanted.
6.1.1 In a multiphase installation, the circuits shall be so arranged that the total load is, as nearly as is practicable, balanced between the phases of the supply.

I really, really, don't suck all these things I say out of my thumb. Really, I promise.

And yes, as others have said, you can get max 60A on a single phase. If you need more than 60A (for whatever reason), a three phase installation is a must. I've personally worked in residential houses with elevators and escalators and stuff in them :D
 

greg_SA

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#20
6.1.1 In a multiphase installation, the circuits shall be so arranged that the total load is, as nearly as is practicable, balanced between the phases of the supply.

I really, really, don't suck all these things I say out of my thumb. Really, I promise.

And yes, as others have said, you can get max 60A on a single phase. If you need more than 60A (for whatever reason), a three phase installation is a must. I've personally worked in residential houses with elevators and escalators and stuff in them :D
I never said anything about the regulations - was talking about what happens in practice... so I'm not disagreeing with you.

I have my geyser and oven on one phase... So in the evening, I am drawing almost everything from that phase, and almost nothing from the others. So my understanding is that it is not a technical requirement for your house... is is just what is ideal from a distribution point of view?

The fact that the 3 phases are balanced higher up stream (taking many houses together into account) is just random...
 
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