Three Phase Domestic Wirng

[lesrj2005]

230v 50Hz Supply Thailand

I have been requested to supervise electrical installation work on a five bedroom house, with 4 x 6Kw heaters 2 x 8Kw cookers and 8 x Air condition units plus a motorised gate and the rest will be sockets and lights, at what point must i consider using a three-phase supply or will I be able to use a single-phase supply for this installation.

And what load would be acceptable for a single-phase supply

 

[plugwash]

How much load you can put on a single phase supply depends entirely on how big a single phase supply they will give you.

If we start with the assumption that heating and aircon loads are likely to be similar and that the heating and aircon in a particula room won't be used at once then we are talking a lot of current. If you went single phase it would have to be at least a 250A suppply and i think its fair to say you will have trouble getting a single phase supply that big.

So it seems 3 phase at 80A or 100A per phase is in order.

I would also stronly consider using a biderectional heat pump system that could do the job of both heating and air conditioning.

 

[JohnD]

you should be able to get 3-phase cookers and aircon units, and any water heating. All of these will be fixed appliances. That may enable you to put sockets and lighting on single phase as you will not be anticipating any other large loads (but look out for electric showers or portable heaters and aircon, especially in staff accomodation which may not be provided with the same quality of heating and cooling as the family rooms). A 3-phase cooker will also not dim the lights as much as if you were all on one phase.

Sockets all on one phase are safer as the voltage between phases is higher so shocks are more severe. We used to be quite strict on having sockets in different phases near to each other, but it can happen (even if you have one phase per floor) when people plug in a hoover or extension lead at the top of the stairs and work down.