new house 3phase heat pump

[glasgospark]

new house guys with a new heating system through mcs real scheme

3 phase supply run into house the pump is the only piece of equipment requiring 3phase ,

question is looking for best way to do this was thinking give the house itself the normal dual rcd db then from 3phase mains to lucy blocks fuse down for pump.

pump is situated in the same location as main cable head ,

4kw 32a 3phase supply required via rotary isolator


any views ?

 

[ipf]

A heat pump mate, not a central heating pump. As in air to air or air to water.

Misread, pal. Single phase available for domestic though, surely?

 

[stidge]

Tony, I take it that's right about not having to balance phases on a domestic, that helps me with an upcoming project mate! Thanks

 

[Jimsparky]

You would have thought so ? Would be 20 amps roughly

 

[Engineer54]

If you have a 3 phase supply and a 3 phase meter, don't run away with the idea you can have a small 3phase DB just for the heat pump and accessories, and the rest of the install on a single phase CU!! That will leave two of the phases doing little to nothing, which is definitely not the way to go about things. If a small heat pump is the only load that requires 3 phases, then look around for a suitable single phase heat pump.

 

[Knobhead]

So the DNO runs a 3Ph cable with single phase branches to individual properties. They balance the loading by alternating the phasing. As I suggested.

Regarding 3Ph metering, it is cumulative addition of each individual phase. Unless someone changed it in the last 40 years while I’ve been dealing with it and didn’t let me know. Imbalance does not affect the cumulative reading.

@ 230V Ph to N
R 4A
Y 35A
B 4A
Equals 9.89KVA no matter which way you look at it.
The neutral current would be 31A

 

[Rockingit]

Sounds like a lot of over complication to me...3ph in, 3ph board, 3ph to GSHP, n X 1ph RCBO's for the rest of the place as required.

 

[glasgospark]

3 phase supply is solely for this property , stand alone building .

customer has went to heating company who have designed this system 3phase 32a supply is whats been asked for.

must be a single phase system but thats whats been asked for and i need to quote accordingly , thinking of a 3phase db with rcbos

 

[guest119]

Sounds like a lot of over complication to me...3ph in, 3ph board, 3ph to GSHP, n X 1ph RCBO's for the rest of the place as required.

Problem there is the number of ways available for domestic.
A 4way tp db would only leave 3 ways for the rest of the install, 6way tp db 5 ways free, etc etc.
Tp dbs aint cheap.

 

[Engineer54]

So the DNO runs a 3Ph cable with single phase branches to individual properties. They balance the loading by alternating the phasing. As I suggested.

Regarding 3Ph metering, it is cumulative addition of each individual phase. Unless someone changed it in the last 40 years while I’ve been dealing with it and didn’t let me know. Imbalance does not affect the cumulative reading.

@ 230V Ph to N
R 4A
Y 35A
B 4A
Equals 9.89KVA no matter which way you look at it.
The neutral current would be 31A

Ah, but would anyone here actually design and install such a lash-up in a domestic environment?? This installation doesn't need a 3 phase supply at the end of the day, it's not really a question of balancing and cumulative addition of metering individual phases as such.

 

[Engineer54]

3 phase supply is solely for this property , stand alone building .

customer has went to heating company who have designed this system 3phase 32a supply is whats been asked for.

must be a single phase system but thats whats been asked for and i need to quote accordingly , thinking of a 3phase db with rcbos

Which could well be a very expensive solution, a good solution none the less though!!

 

[somersetsparks]

problem Is for the customer, they will be subject to commercial energy bills if they use a 3 phase supply, not your usual fixed deals etc. or confused.com lol

 

[Guest55]

if the customer has paid the £3-4000 the dno's usually charge for a 230 to 400v domestic upgrade then the £2-300 for a 3ph DB really is small change within the projects total cost , and will facilitate flexible balancing of the circuits.

 

[Knobhead]

If the supply is there then utilise it. The economics don’t interest me, it wasn’t in the original question.

 

[Guest55]

If the supply is there then utilise it.

exactly.
;-)

 

[Outspoken]

3 phase supply is solely for this property , stand alone building .

customer has went to heating company who have designed this system 3phase 32a supply is whats been asked for.

must be a single phase system but thats whats been asked for and i need to quote accordingly , thinking of a 3phase db with rcbos

But you clearly have no experience of 3 Phase and no understanding of the dangers, regulatory requirements and the basic maths or you would have had some serious alarm bells ringing before making your OP here.

The basic maths has already been demonstrated in this thread, I would suggest if you truly want advice you either call in an industrially/commercially experienced spark who works on 400V supplies, or you get the paperwork for this unit, read it and then perhaps scan and post the spec page on here for people to read.

We are not Mystic Meg, we are not able to solve your problem from your rather poor posts.

I am sorry if my comments sound harsh, but have you even experienced a phase to phase fault, I'll bet not, have you even had a shock across two phases of a supply, I'll bet not...you get this wrong you could very easily kill yourself or the homeowner, so stop messing about and do the job properly, and that includes seeking advice.