How many electrical circuits?

Hi all
Any sparkies out there?

Building a house and it is coming with electrical circuits as follows.
1x GPOs
1 x aircon
1 x oven
1 x lights

Someone else I spoke to recommended having at least two electrical/ lights and 2 power.
Is what is already provided 2 of each? GPO and oven = 2 power and air on and lights = 2 electrical?
Or, is it better to have 2 separate power, and 2 lights and have the house seperated somehow. Advice has been to split it roughly across half way which to me seems to split the "load" of lights/ applicances, type thing.

Haven't had much luck with this issue, so any advice would be appreciated!
Thanks

In my new build, I'm putting on a power circuit per room, all with their own MCB/RCD back at the circuit board.

For many this would be overkill, but for me it is something I want to do. Top of the range Hager single pole RCD/MCD's are around $45 each, so one of these per circuit, although there are cheaper brands that do the same for a lot less.

Definately do what has been suggested, split your home in half and set basically a power circuit and a light circuit for say the front half, and another for the rear half. So two power circuits and 2 light circuits.

I would consider a separate power circuit for either the garage and kitchen or both.

As it stands, if you trip the lights circuit, you have no lights in your house until to rectify the problem.

I assume your a/c is a ducted one, but if it is a split system like myself, I would pre-wire and pre-install for other split systems. In my case I'll eventually have 5 separate split systems in my new home, and I've already got the a/c piping and electricity run to all of them, but it might take me another year before I get them fully installed. It's a lot cheaper now to do it than later.

Just a quick add up for my build is 4 light circuits (front, back, garage, and HT room), 5 a/c circuits, stove/over circuit, 9 power circuits, so roughly 18 MCB/RCD's on my circuit board inside the garage.
As I said before not something most people would do, but I believe you should go just a tiny bit more than the basic, although not to my extent.

Hi there.
Thanks for your response! You do have a lot of circuits but like you say it's what you want!
Would it also assist then if I got the aircon on its own circuit and also the oven? Aircon is ducted, yes.

Cheers

I also just found this link which helps me figure it out visually too (wiring ain't my thing!)

http://www.actewagl.com.au/About-us/The ... cuits.aspx

It might also help others.
Think I will definately add oven and aircon on their own circuits.

Most definately, separate circuits for them.

The A/C will require its own circuit because of current draw, likewise with the stove/oven, as it too draws a lot of current.

If you put either on a 16amp standard power circuit, it'd trip the circuit breaker all the time.

Interesting link that one.

Just don't understand why they are talking about 120volts on an Australian site.... clearly copied from a USA site without considering the relevance to Australia.

Using the 1200 watt hairdryer example, at 240volts, that's a 5amp draw rather than 10 amps. or to be pedantic at the rated 230v we are now rated at, that's 5.21 amp draw.

The diagram clearly indicates that the 'average house' has two power and two light circuits. A single power circuit for a whole house could easily get overloaded to the extent that it would be tripping on a regular basis, i.e. ~3800 watts of devices on the one circuit would trip it.

Hi Beazley77
I am a licensed electrical contractors in WA

As per our wiring rules min 2 circuits for power
Depending on how many lights you have usually
small house only 1 circuit
All separate circuits ie air con, oven, hws
are to be on a separate circuits.

When wiring up a new dwelling the normal practice
is to segregate heavy loaded areas such as
kitchen & laundry. So in tail I would be
thinking 5 x 16-20A circuits, Sep circuits
for air con and oven, and probably
as said above 2 circuits for lighting.

Is your in-coming supply single phase or three phase?
With 3 phase you can evenly spread the load.

Kitchen - 1 x 16-20A
Laundry - 1 x 16-20A
Fridge & Dishwasher - 1 x 16-20A
Split rest of gpo's over 2 circuits
1-2 10A circuits for lighting
Min 2 RCD's for protection or use RCD/MCB
and spread 1power and 1 light over the protection
devices. Max 3 circuits per 1 40A RCD 30mA
So as said before above if a fault occurs
and trips RCD hopefully it only takes
out that protection device.

Hope this helps

Oops,I didn't even notice is was 120V and we are 240V (or close to). I get the math though.

Thanks for your help. I'm sure others will find this useful thread now too.

You say minimum 2 RCDs. If I had 8 circuits (2 lights, 2 power, 1 aircon, 1 laundry, 1 fridge/dishwasher and 1 oven), what would be the ideal number of RCDs? And how much extra would it be roughly? My power is only 1 phase. No pool, spa or power hungry tools in garage .

As was also mentioned you can get MCB/RCD combined in the one switch, and whilst more expensive, it will them mean you'd have 8 RCD's, so when one tripped, you'd be able to isolate the issue far more readily than with just 2 RCD's.

He did mention a minimum of 2 RCD's, as I know a former girlfriends house had one RCD across the entire house... trip it and everything went black.

Hi Beazley,

Hard wired circuits are usually Ovens, Air Cons, Hws (some HWS these days only require a WP GPO) Thus being "hard wired" it means there is no direct contact with any live parts so not needing to be protected by a RCD. These circuts are only protected by Circuit Breakers, they are designed to trip if there is over current due to maybe short circuit.

As per AS minimum of 2 RCDs is the requirement, so if tripped and cannot be reset due to an appliance or lighting point being in fault/grounded then at least you still have another RCD which may supply to other power & light circuits. This may happen in the early hours of the morning or in storm conditions you may not be able to get Elec Contractor out to rectify, though you still can function on other circuits.

Any power & light circuit must be protected by a RCD or a RCD/MCB As per AS, which was explained above combined Circuit breaker and RCD!
This also includes and 15A single circuits (sometimes spas have a plug on them and require a WP GPO)

The AS requirement now for 40A 30mA RCD's is 3 circuits to one RCD. As there is not allot of room in domestic switchboards it would be wise to use RCD/MCB as it saves space as only takes up 1 pole.

Hope it helps
Max load for a single phase is 63A consumer supply cable mininmum 10mm Sq

Hi, I had a look at a display home on the weekend (Metricon 70sq 2020 build), and had a look inside the meter box; seems like very few elec circuits? and only one RCD? But wired for 3-phase as well...Meter box CB RCD