# Tripple phase to split phase

1. Jul 13, 2010

### chopficaro

how are the wires wrapped on a transformer that converts from triple phase power distribution to split phase outlets?

2. Jul 13, 2010

### dlgoff

3. Jul 13, 2010

### chopficaro

yes, but it must be BALANCED, how would they maintain balance if all the loads are not equally shared on all 3 phases?

4. Jul 13, 2010

### dlgoff

This is in my opinion since I don't have first hand information as to how, since it would depend on how the supplier operates their business, but... When they install residential transformers in a city or in rural areas where it is easier to string one wire, the power company would wire the areas according so a plan so to maintain a phase balance. Power is transmitted from power generation station to large substations that then ship the power to distribution substations. Here at the distribution point is where you would need watch. So depending on the situation, when unbalance occurs you may be able to switch some of the load around. If all three phases are available at the pole, it would be a simple matter to switch the wiring to a different phase.

5. Jul 13, 2010

### Staff: Mentor

Power distribution is always 3 phase and it is converted to single phase locally. Pole mounted transformers you see outside some neighborhoods are where it is done:
http://www.powertransformer.us/polemountedtransformers.htm

6. Jul 13, 2010

### chopficaro

tyvm, very informative, this has been bothering me for some time

7. Jul 13, 2010

### dlgoff

Just a quick note. In the rural area where I live for example, there are only two conductor strung between the poles that service many square miles. So that means that to balance the transformer loads on their "distribution" substation, moving loads to a different phase would be impossible without building a new line. Unless there are several lines by design coming from each phase to start with that could be switched at the station, which I think is very unlikely.

8. Jul 14, 2010

### sophiecentaur

I think they work on the statistics of large numbers. If they share out the phases between equal numbers of similar consumers then the demand will balance out 'near enough'. In the UK, they tend to have a single, three phase, transformer which has sets of three single phase (plus neutral) pairs, radiating out along the streets in a locality. The phases tee off to each house, in turn,so each house gets a phase different from its two neighbours. Of course, we use 230V supply for everything so we do not need a special split phase supply for heavy domestic loads. A 100A fuse is about the maximum you will ever (?) find in a domestic situation.
I imagine the average length of supply line is much shorter in the UK than in the US - There are more remote dwellings in the US and even the cities in the US (with a few exceptions) have more space between dwellings.