I'm considering having 3 phase installed

[jouleflow]

Hi

I currently have a 100A single phase supply ( forgive the pun ) & I am considering asking for 3 phases to be installed. I have some workshop equipment that I want to install which are 3 phase and total about 30kW.
My property is fed by 2 cables overground on 7 telegraph type poles. My neighbour has 3 phase to a pole outside his house directly from a transformer. From the pole at my neighbours I am the only other consumer & I use one of the phases. So there are only two of us supplied from the recently upgraded transformer. It looks like I need a further two phases from the neighbours pole ran alongside my existing feed & associated consumer unit.
My questions are:
Do I have to use Western Power for the quotation?
Are there any other companies who can do this work?
Does anyone have experience in this type of installation & a rough guide to a price?
Is there a " standard " domestic 3 phase supply, I seem to remember reading something like 3x60A was below a threshold.
Can I still use economy 7?

Thanks in advance

Greg.

 

[telectrix]

only DNO can upgrade your supply. if that's Western power, then you need to get them to quote. mymate recently had 3phase installed. cost £7000, but they had to close a road to get cable from tother side of street.

 

[Andy-1960]

Hi, yes you will have to apply to Western Power to have your supply upgraded, you will be responsible for the upgrade work in your property, new three phase distribution board etc and you will also have to liase with your electricity supplier to get your meter changed.

I do not see any reason why you would not be able to continue with your economy seven but I personally have not seen this on a 3 phase supply, again you will need to enquire with your electricity supplier about this.

Cost is anybody’s guess I’m afraid.

 

[jouleflow]

only DNO can upgrade your supply. if that's Western power, then you need to get them to quote. mymate recently had 3phase installed. cost £7000, but they had to close a road to get cable from tother side of street.

Thanks, at least mine is in a straight line about 50 metres overground on the same side of the road, so might be close to that price.

 

[snowhead]

And the recently upgraded transformer may need to be upgraded again for you, for which you may have to contribute.

 

[jouleflow]

And the recently upgraded transformer may need to be upgraded again for you, for which you may have to contribute.

Apologies in advance for the following question.
Are 3 phases of 60A much more load on the transformer than one phase at 100A

 

[snowhead]

Apologies in advance for the following question.
Are 3 phases of 60A much more load on the transformer than one phase at 100A

Yes, +60 on each of the other 2 phases but -40 on your phase.
It will have been upgraded (or maybe just replaced like for like) for a reason which won't be for you as they won't have been aware of your plans.

 

[telectrix]

Apologies in advance for the following question.
Are 3 phases of 60A much more load on the transformer than one phase at 100A

3 phases @ 60A per phgase equates to approx 180A total load.

 

[jouleflow]

3 phases @ 60A per phgase equates to approx 180A total load.

Thanks for that, I feared it would be that simple. Many years ago I thought that phases partly cancelled each other out. I must have this confused with something else.
With my neighbour using all 3 phases & my usage doubling the load on one phase then I hoped that reducing the load on my phase by 40A, there would be spare capacity to increase the load on the other 2 phases & possibly balance the transformer load better.

 

[PEG]

Hi,could we ask what the increased load,will consist of?

 

[snowhead]

Many years ago I thought that phases partly cancelled each other out. I must have this confused with something else.

You're perhaps thinking of;
If the load is perfectly balanced across all 3 phases then there is no Neutral current.
If the phases partly cancelled each other, you'd be getting something for free.

 

[jouleflow]

Hi,could we ask what the increased load,will consist of?

There will be a compressor - lathe & 2 milling machines only two of which will be used simultaneously. The total running Amps is 15A and the highest startup machine is 12.5A.

 

[PEG]

If it is commercial/business,then the justification is stronger,but if it hobby/passion related,i would spend a fraction of the money,setting up things,so your present supply was sufficient. On what you have stated,this would not be expensive.

This could be time managed,or interlocked,or similar....you would have a spare wedge,to blow on a handsome Harrison,or Jap jig-borer

 

[jouleflow]

If it is commercial/business,then the justification is stronger,but if it hobby/passion related,i would spend a fraction of the money,setting up things,so your present supply was sufficient. On what you have stated,this would not be expensive.

This could be time managed,or interlocked,or similar....you would have a spare wedge,to blow on a handsome Harrison,or Jap jig-borer

Thanks,
Do you mean 3 phase inverters? I have looked briefly at these a while ago, do they provide a stable output to run cnc machines - do you have any preferred suppliers.

 

[Fazz711]

Hi.
Modern single phase to three phase inverters are very good.
They can take some setting up with all the parameters avl.
We use them a lot at work with all sorts of machines being run with them.
I have set one up at home to run a meddings pillar drill and it works well.