Im looking at putting a three phase supply to my house to power a german built heatpump...

In the heatpump manual is says it wants a 400V 3ph supply....

Does this mean that L1, L2, and L3 are 400v, or that they are 130V each?..?.

Is a UK 3ph supply 400V? and if so, how do I use that to power my exsiting 230V house?

Argh...its so damn confusing!

No!
A 3 phase supply is 415V between phases and each phase is 240v between phase and neutral.
I hope you have deep pockets as your electricity supplier will charge anything from £1500 to £5000 to install. They will also install a 3 phase meter, which will cost you more.
Why a 3 phase pump for a house?

400v 3 ph is 230 v per phase. To power the house you just use take one phase connection off the 3 ph supply. Don't underestimate how much 3 phase is going to cost you to get put in.

Im just looking at possiblities here...nothing is set instone...

The problem is, that the heatpump required to heat the house is quite large, and they only make three phase heatpumps of that size....

There is no harm in getting a quote from the power company for a three phase supply...

But once the installation is done, I assume they will only charge for the electricity we use, and wont charge other fees just because we are running 3ph?

And would I be correct in assuming, that as the house idealy needs 60A and the heatpump requires 25A that I should be getting a threephase supply capable of supppling atleast 70A per phase? (or can I get a smaller supply and divide the house load between the phases?

As for the difference between 400v and 415v or 230v and 240v there isn't one as all electricity supply voltages vary with system load. The UK used to be 240v + or - 6% with european harmonisation it went to 230v + 10% - 6% classic european bodge job. No electrical equipment or supplies were changed.

Your pump will work fine in the UK so all you have to worry about is cost.

You can buy single phase to 3 phase converters but they will cost more to run.

The 3 ph will cost you more in standing charge just look at one of the suppliers websites for costs. Take the minimum size you can get usually 60A it will do fine and take the house off just one of the phases. You will need a competent electrician to do it as well due to the new part P regs and the Electricity company required certification

As far as I know you can not (or should not!) distribute a dometsic supply accross more than one phase.

If the 3 phase is just for the heatpump compressor motor, you could use a large inverter, single phase input units are available up to about 4kW, these would probably run 5.5kW in a heatpump. The other proviso is that the motor terminal box will let you connect in delta so you can get full torque - most motors that size are wired like this nowadays.
You'd need to wire it to the electric cooker/shower supply....
Bob

Discussion on ground source heat pumps (~ 2kW?)
http://tinyurl.com/2tx6gv

Chears guys.

Spoke to the power company and indeed they do want silly money not only for installation but to provide the service...

So I spoke to a company who specialise in sold state 415V 3ph inverters....

They can supply a single box for a heap of cash that will happily feed straight into the contactors in the heatpump...I can then run the heatpump controls of an un-inverted normal single phase supply...

Although the inverter is expensive, it doesnt waste a huge amount of energy...

Looks like a good possibility

quote:

---

Originally posted by MikeRJ
As far as I know you can not (or should not!) distribute a dometsic supply accross more than one phase.

---

quote:

---

Originally posted by iank

quote:

---

Originally posted by MikeRJ
As far as I know you can not (or should not!) distribute a dometsic supply accross more than one phase.

---

I believe you are correct in that it's probably illegal. I'm sure I was told in a previous company that each floor (at least) must be on the same phase. I'd expect all the power in a domestic situation to be on the same phase (though different houses in the same street will vary which phase they are connected to IIRC).

---

quote:

---

Originally posted by nitram38

quote:

---

Originally posted by iank

quote:

---

Originally posted by MikeRJ
As far as I know you can not (or should not!) distribute a dometsic supply accross more than one phase.

---

I believe you are correct in that it's probably illegal. I'm sure I was told in a previous company that each floor (at least) must be on the same phase. I'd expect all the power in a domestic situation to be on the same phase (though different houses in the same street will vary which phase they are connected to IIRC).

---

Sorry boys, you are both completely wrong!!!!!!!!!
No regulation exists that says you can't have 3 phase anywhere as long as the correct installation methods are used and warnings stickers/labels are on the relevent equipment.

---

I am not going down the he said we said route. There are too many "experts" here sometimes.
What you are talking about has nothing to do with the original question of a 3 phase supply to domestic premises.
I have been an electrician for 27 years.
No regulation exists that says you can't have the different phases in one property or even that it has to be on different floors.
Like I said, if you use the correct installation methods (which I think covers good working practice regarding sockets adjacent to each other) and warning labels etc it is ok.

quote:

---

Originally posted by nitram38
I am not going down the he said we said route. There are too many "experts" here sometimes.
What you are talking about has nothing to do with the original question of a 3 phase supply to domestic premises.
I have been an electrician for 27 years.
No regulation exists that says you can't have the different phases in one property or even that it has to be on different floors.
Like I said, if you use the correct installation methods (which I think covers good working practice regarding sockets adjacent to each other) and warning labels etc it is ok.

---

quote:

---

And would I be correct in assuming, that as the house idealy needs 60A and the heatpump requires 25A that I should be getting a threephase supply capable of supppling atleast 70A per phase? (or can I get a smaller supply and divide the house load between the phases?

---

quote:

---

Originally posted by nitram38
No regulation exists that says you can't have the different phases in one property or even that it has to be on different floors.

---

quote:

---

Originally posted by MikeRJ

quote:

---

Originally posted by nitram38
No regulation exists that says you can't have the different phases in one property or even that it has to be on different floors.

---

No regulation exists to say I must always wear goggles when using my angle grinder, but I'd be stupid if I didn't.

The point being having multiple phases on sockets in close proximity to each other is a safety risk, and even splitting across floors in a domestic situation were extension leads are often likely to be used doesn't seem too clever.

---

Found a reference pretty quickly which seems to imply separation of phases was a requirement before 16th edition came in:

http://www.abtt.co.uk/forums/index.php?s=a6245ac84f02e93d9a877dfb650674d3&showtopic=970&st=0&#entry4416

See the post by someone called gareth:

quote:

---

It's not a question of there being a document that says "you can" - more one of there no longer being a document that says "you can't". There used to be a section concerning phase separation in the IEE wiring regulations, but that part of the regs disappeared with the 16th edition.

---

shouldn't be silly money - should be a couple of hundred - eg
http://uk.farnell.com/jsp/Industrial+Controls+&+Automation/Motor+Drives/OMRON/CIMR-V7AZB4P00/displayProduct.jsp?sku=3181704
OK it's silly money from the catalogs..... & the cheaper suppliers (mitsy, siemens) didn't have a 4kW in farnell
Bob

quote:

---

Originally posted by iank
Found a reference pretty quickly which seems to imply separation of phases was a requirement before 16th edition came in:

http://www.abtt.co.uk/forums/index.php?s=a6245ac84f02e93d9a877dfb650674d3&showtopic=970&st=0&#entry4416

See the post by someone called gareth:

quote:

---

It's not a question of there being a document that says "you can" - more one of there no longer being a document that says "you can't". There used to be a section concerning phase separation in the IEE wiring regulations, but that part of the regs disappeared with the 16th edition.

---

---

So can you remember what 15th edition said about phase separation? Seems my source was still hanging on to the wisdom from his original training

25A... that must be 1 hell of a pump!

A 3 to 4" heating circulating pump for a commercial premisis only draws about 10 amps max.

Is the 25A Just a start up current?
in which case if started slowy by and inverter it would be much less.

quote:

---

Originally posted by iank
So can you remember what 15th edition said about phase separation? Seems my source was still hanging on to the wisdom from his original training

---

The only place I've ever seen 2 or more phases used in one house is where one is feeding storage heaters, and even that doesn't happen too often. Only really big houses/industrial places need 3 phases, as 1 is good for 100A in most areas.
If you can find a way of not using 3 phase, I'd go that way as I know what BG charge for theirs! It'll take ages to get put in and cost a fortune. If you're careful a single phase for the house will do fine, unless you want loads of power showers/storage heaters and big electrical gear.

quote:

---

25A... that must be 1 hell of a pump!

---