johnbc

Thank you all for your help. I will update after getting the new supply from the PEA.

Thank you Crossy for you help. I think that in my place they don't have a single phase 30/100 meters. I would like to be on the safe side because I may one day add another AC, so I think I would go with a 15/45 3 phase system. I have been to an electricity shop and was looking at a 3 phase distribution box. They have a Square-D box. I also would like to have an RCD to protect agains ground fault. They offered me a an expenssive separate ELCB SafetyCut box that should be connected before the main DU. They said that there are no RCD's that are part of the Sqare-D system. Are they right or it is possible to have the RCD as an integrated part of the three phase load balancing consumer unit?

Thanks

The second figure on the meter rating is the rated current 45A for a 15/45. In reality these things are incredibly robust and can handle a 100% overload without blinking.

To your supply requirements.

Forget the fridges, washer and oven etc. for now, these are intermittent loads and don't really affect things.

Big draw kit:

3 x 18k A/Cs @ 2,000W = 6,000W

3 x 6k water heaters @ 6,000W = @ 18,000W

With all that on you're at 24,000W about 110A

But you are highly unlikely to be running all your water heating and A/C together, applying diversity we can get you down to:

A/C = 4,000W

Water = 9,000W

Total 15,000W or 68A

As to what supply you need, that's down to what's available.

You could get a 30/100 single-phase supply, which would meet your needs easily, but it's not available everywhere. You need to ask your supply authority.

If you can't get 30/100 then you are looking at 3-phase, a 15/45 would be more than adequate.

Alternative solution: Get tank type water heaters, they're about 3,000W each, but even with 3 we can get the water heating load down to 3000W using diversity. That would get you 7,000W, 30A well within the capability of a single-phase 15/45.

It depends on your lifestyle, but in reality, a single-phase 15/45 would likely be just fine, we have a similar sized home on a 15/45, our (measured) peak load is about 10kW but only for a few minutes each morning.

Thank you for your reply. It is actually 181 Amps. Here is my rough estimation of maximum current per all my appliances...

It might be lower but I put a margin of about 20-25% for each.

3 Air Con 18,000 BTU = 2000 * 3 = 6000
3 Water Heaters = 6000 * 3 = 18000
Washing machine = 1000
2 Refrigerators = 1000 * 2 = 2000
oven = 3000
Misc. max 1500+1500+2000= 5000

total 40000 Watts = 181 Amps

Is there a mistake I did in this calculation?

Hello,

I currently have single phase supply to my house and the meter is 5/15 . I am renovating my house an I will add a lot of appliances so I will need to order a new meter and to rewire the cables and buy a new breaker box.
After calculation it seems that maximum power draw if all appliances will work concurrently is about 160 Amps. What does the meter 5/15 or 15/45 actually means, how much continuous current it can provide? Do I need a single phase or 3 phase supply and what type of meter should I order?

Thanks