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 ?

 

[glasgospark]

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.

done alot of 3phase actually mate , lv main panels ect

but never done a new build with the need for 1 circuit for heating to be 3phase

i understand the 400v between phases.

 

[Outspoken]

done alot of 3phase actually mate , lv main panels ect

but never done a new build with the need for 1 circuit for heating to be 3phase

i understand the 400v between phases.

Well then I do not understand your dilemma, you OP made it sound as if you did not understand how to connect this up, if you do, then why the post...do you understand the confusion here?

 

[glasgospark]

Well then I do not understand your dilemma, you OP made it sound as if you did not understand how to connect this up, if you do, then why the post...do you understand the confusion here?

Just not sure what design to go with with regards to mains db etc

 

[Guest55]

how many 230v circuits in the property ?
if theyve room for a say 4 or 6 way 3ph DB , then thats what i'd use as you can put any load on any phase then.

 

[guest119]

Seems to me this is exactly what the ELECTRICIANS FORUM should be.
Electricians helping each other and putting forward ideas and suggestions to each other.
Maybe the stick should be saved for the ones that shouldnt even be on here and have the cheek to ask us for advice, Electrical Trainee, di etc.

Boydy

 

[glasgospark]

how many 230v circuits in the property ?
if theyve room for a say 4 or 6 way 3ph DB , then thats what i'd use as you can put any load on any phase then.

The house is pretty bug hence the 3phase heating , but all there is are sockets lights smokes and cooker all lights led ,



Would there be a problem using L1 for all house and using the 3 phase for the pump only. Balancing the phases in this situation will be next to impossible

 

[Guest55]

well if youre max demand after diversity is little more than 60A , and it sounds like it is , then maybe you could dump the whole house on 1 phase with a standard CU and then seperate tails to a 3 pole switch fuse for heating ( plus 3 pole rcd if your cable isnt surface fixed.
as tony mentioned , balancing isnt too vital for a domestic , unltimately its the dno cable that takes the strain , just a higher bill tarrif for the customer.

 

[johnboy6083]

Options:

1) straight out of cutout into henleys. From henleys, take cables to a 32A switchfuse for the heat pump. Take a cable from one phase & neutral & earth, and feed a small CU.

2) feed a TP&N DB from the cutout, and use all three phases across the house. Its Almost impossible to balance any circuits properly in a domestic setting anyway, due to the timing of the loads.

 

[guest119]

Options:

1) straight out of cutout into henleys. From henleys, take cables to a 32A switchfuse for the heat pump. Take a cable from one phase & neutral & earth, and feed a small CU.

2) feed a TP&N DB from the cutout, and use all three phases across the house. Its Almost impossible to balance any circuits properly in a domestic setting anyway, due to the timing of the loads.

Option one would be a 100amp switch fuse with 32a fuses, not a 32a switch fuse.
Also then you have 2 main switches for the install instead of one.

 

[Knobhead]

I’m surprised no one has suggested a single phase supply. A smallish inverter would take care of the 3Ph heat pump.

The real and logical method was mentioned earlier, change the HP motor to single phase.

 

[GLENNSPARK]

well if youre max demand after diversity is little more than 60A , and it sounds like it is , then maybe you could dump the whole house on 1 phase with a standard CU and then seperate tails to a 3 pole switch fuse for heating ( plus 3 pole rcd if your cable isnt surface fixed.
as tony mentioned , balancing isnt too vital for a domestic , unltimately its the dno cable that takes the strain , just a higher bill tarrif for the customer.

still a lot of 3 1/2 core paper leads about though Biff....
or am i reading into this too much?

 

[Knobhead]

still a lot of 3 1/2 core paper leads about though Biff....
or am i reading into this too much?

The neutral current isn’t constant through a street service cable.
House “A” will cancel out houses “B&C”.
Before the days of modern household electrical gizmo’s the neutral was more or less a 0V reference.
Mrs. Red’s iron would cancel out Mrs. Yellow’s kettle and Mr. Blues oven.

 

[snowhead]

Mrs. Red’s iron would cancel out Mrs. Yellow’s kettle and Mr. Blues oven.

That's Mrs Li, Mrs Lii, and Mr Liii....

 

[ipf]

That's Mrs Li, Mrs Lii, and Mr Liii....

Can't call 'em 'blacks' and 'browns', even if there is a bit of grey in there. Have the race relations board on you.

 

[johnboy6083]

Option one would be a 100amp switch fuse with 32a fuses, not a 32a switch fuse.
Also then you have 2 main switches for the install instead of one.

You only require one point of isolation. This is primarily the cutout. I agree that one switch in front of everything is best, but only if the customer will pay!

Why would it be a 100A switch? You can get 32A switchfuses. Socomec make them among others.