Installing and ongoing costs of 3 phase power

On completely new rural section - I would like it for my shed for welders/machinery etc but dont really want big ongoing costs - I can wear the higher install cost assuming its not stupidly high - the run is about 130m from transformer.

Anybody have it connected?

Have you thought about a single to 3 phase inverter? I got one for a customer for running lathes and cnc machines, worked very well,
http://www.eurotech.co.nz
3 phase has dearer monthly rental generally

we run 3 phase at work but in our aera all homes are 3 phase anyway.
what size welders etc. it would a be a fairly big welder to require 3 phase.
but if you ave enough machines running at once, you may overload a single phase circuit and would need 3 phase.

talk to sparky and power co first. 3 phase changes the way things get wired.

single phase to 3 phase inverter is not going to run welders.
we have a few for running variable speed on pumps. the plus is that big 3 phase motors are often cheaper than big single phase motors (especially 2nd hand).

One thing you can guarantee; it will be stupidly high :-/

We have 3 phase into our house, about 60 - 80 mtrs from the road, it did not and does not cost a fortune every month.

Why 3 phase in a house ? Just curious.

Yes I had 3 phase electricity installed on my rural farm/lifestyle property and it didn't cost much more than 2 phase which they were prepared to install. They won't usually install single phase electricity in rural areas because they can easily end up with an unbalanced load on their network.

The cost of running it is just the same as single phase, you simply pay for the amount of electricity (kwh) that you use.

I recommend it because 3 phase underground electric cables can carry much more power than single phase cables for a given cable cost.

Three phase electric motors are more efficient than single phase electric motors and you can use really big electric motors whereas with single phase you are limited to 3HP. Second hand three phase electric motors are usually quite cheap to buy and you can also buy any machinery that requires a three phase supply.

Three phase is necessary if you want to operate high current welders, or at least "two phase" (400V).

Its also a good idea to run your house on three phase so as to keep the load on all three phases balanced and thus keep the current in the neutral line as low as possible.

If you require any further info. don't hesitate to ask since if I don't know the answer, somebody else will (I hope).

This is kinda confirming what I was told, I was told also about 3 phase motors using less energy. Also it is only one extra core to run which isnt gonna change the cost that much.

Interesting comments about ongoing costs - I like the one about pay for what you use and no more!

I have heard an inverter from single to three phase of decent quality and size can be around 4k plus install - Cheaper to run the extra core I would guess.

I dont think so considering its a new install - I will find out, its only the extra core. and a different meter.

Make sure you compare the monthly line costs too.

It would be good if you got back to us and let us know the outcome.

Good luck!

Well timbo, I wouldn't worry about the energy meter as that belongs to the lines company although I can't remember whether you have to pay to have it installed, but I think that it is installed at the time your line is connected to the network so its installation will be covered under that cost; if that is the case.
The line cost is dependant on the current rating of the line fuses that you choose to have installed and I'm fairly sure will be the same for a three phase supply as for a single phase supply to supply the same amount of power. The only difference is that you would get a 90Amp fuse for a single phase supply whereas for a three phase supply you would get three 30Amp fuses although you can request larger fuses if you want to run a lot of high current equipment at the same time.
My network (line) charge is 19.17c per day or $5.56 per month for a three phase supply with 30Amp line fuses with Network Tasman on a "low daily" scheme (max 8000kwh per year). I also pay Meridian (my electricity retailer) 19.16c per day(low daily scheme) as a site charge although I don't know what this is for.
I don't know what the line charge for a single phase supply would be but I think that it will be exactly the same, although line costs vary dependant on your "lines company" i.e. your location. The cost of the energy that you use depends on the electricity retailer that you choose.
In my opinion you get all the advantages of three phase electricity for the relatively small additional cost of a three phase cable rather than a single phase cable. I am sure that it will turn out to be the best decision that you ever made because the cost of changing to a three phase supply after a single phase supply has been installed will be very high.
When you come to get an electricity supply I recommend that you get a written quote that specifies exactly what you will get, from at least three electrical contractors. You might surprised at the differences in their quotes.
Three phase motors are more efficient that single phase motors because you get six "bursts/half cycles" of power compared to two "bursts" of power for a single phase motor for the same interval of time i.e. 20mS.

You can easily find out what your line charges will be; just phone the lines company for your area.

I have my workshop and house on 3 phase. The underground run was 128m and I used 3+screen 25mm copper which cost $16/m. Put it inside 50mm black irrigation hose (not crucial as long as you bed it into sand and avoid rocks) and buried at 1m. Pole fuses are 3 x 40A and cost is 30c/phase (ie 90c/day) line charge plus charged at same rate as any other power. If fuses went to 60A, cost is 42c/phase/day. Advantage is that house lights are split over 3 phases as are other things so if one phase drops, you at least have some juice (a fairly frequent event here). Disadvantage is slight risk of having 400v in house although no one room/outlet is within 2.4m of one on a different phase. Every phase has it's own RCD (even the oven and the HWC run via RCD's).

One of the biggest costs is the cable. If you can source it yourself and not pay retail, you'll be staggered at the savings.

ongoing costs are no different to single.pay for what you use.your in the country so you'll run 3 phase which will be cheaper than single,an aluminium cable is the go and only about $9/metre.

Go for 3 phase more options for running equipment.
Powered up my shed last year around 110M I threw ug phone cable and fibre in my trench as well. Cant comment on running cost as on a higher unit price/no line charge until we build house(From memory)

We recently had 3 phase installed for our relocated house. Had to be underground, so we had a 75m trench dug to the boundary and I dug from the boundary to the pole manually as the digger driver refused to do it. Stony ground so the line had to be in conduit and the electrician also installed new meters, fuse box etc. All up I think the cost was $6500. The electricians steered me towards 3 phase, the cable is more expensive but they said it is simpler for them to wire up.

probably find that the house was already wired for 3 phase. you can't just connect 3 phase to a single phase house.
a few new houses around here had to be rewired as sparky did them as single phase but the supply is 3 phase. opps!

Thanks, kinda what I was thinking

It means that you can use a smaller transformer, run a smaller mains cable and you may be able to use smaller isolators than is everything was on the same phase. And if you are talking motors then you drop a lot of size, weight and therefore cost if you can go three phase. Most rural houses I have wired I have done it on three phase, I was not aware that there is any extra charge, especially now with smart meters that can meter three phase with the single meter.

No, house was a total rewire. Ripped out all of the steel conduit myself to save money, and the original lead sheathed main cable. There was an existing meter box on an outside wall but it was empty except for a mains switch.