Question regarding 400V three phase lighting connected in Delta, without Neutral.

[AReynolds]

I am in the process of designing the electrical installation of a community centre, and have a question about the provision of three phase lighting for a large function room containing 18 36W LED fittings. All of the light fittings are to be switched simultaneously. Would it be possible to connect these lights in a three phase Delta configuration using 400V LED driver units, by connecting 6 light fittings/Drivers to each line, thereby ensuring a constant balanced load on each line? Presumably, I would not need to provide a neutral for each line, and could get away with just providing earthing for each fitting? Does anyone think that this design would be unsuitable?

 

[The Ghost]

Why no neutral, surely the driver requires it. And why not put them on a single phase?

 

[Devonchris]

My thoughts as well.
Or, if the balance of the phases is that critical then a 3P contactor.

 

[snowhead]

You're proposing 400v to the drivers, where are these to be mounted?

 

[telectrix]

for 650w of lighting, that's massive overkill. it's< 3A.

 

[The Ghost]

By the way, what size is this function room?

 

[The Ghost]

it's< 3A.

could be up to 1800A with inrush currents though or even more depending on the driver characteristics.

 

[westward10]

Of course perfectly balanced single phase loads will function perfectly well without a neutral until something fails and then things don't function so well.

 

[westward10]

Is this a wind up.

 

[The Ghost]

Of course perfectly balanced single phase loads will function perfectly well

Is that a wind up?

 

[The Ghost]

Having looked at the content of previous posts..........Mhmmm

 

[westward10]

Is that a wind up?

No because three idential single phase loads will function on a three phase supply with no neutral. Bit yes thisvall seems like a wind up.

 

[telectrix]

how can a single phase load function without a neutral, unless it's 415V s.p.

 

[The Ghost]

Ok because of the phase angle/voltage difference at each 120 degree angle but I can see that on say a single circuit like a water heater but separate circuits, that works? I can't quite think this out. Mmm maybe...why not indeed or even why

 

[telectrix]

the singlephase load requires 240V. the only way to get that from a 3 phase 415V supply is Ph -N, N being the star point.

 

[Lucien Nunes]

If there is such a thing as a 400V LED driver, then yes. There's no need for a neutral and no need for loads to be balanced. Just connect them between any two lines and that's that. I'm not familiar with units that take 400V AC input though. And, uh, why?

 

[The Ghost]

And, uh, why?

Well indeedy, why? Why not just the normal driver etc. What would the manufacturers say.

 

[telectrix]

they'd say you've put 400v across our 230V driver. warranty is void.

 

[westward10]

the singlephase load requires 240V. the only way to get that from a 3 phase 415V supply is Ph -N, N being the star point.

Agreed but the star point requires no connection to neutral. I regularly used to demonstrate this by having three 60w lamps connected across three phases and the neutrals floating and just connected together.

 

[The Ghost]

neutrals floating

Sorcery!