Browse Forums Heating, Cooling & Insulation 1 Nov 15, 2010 10:16 am Hi, We are looking at putting in 3 smallish split system aircon units in our house. For the purposes of this post, assume nothing greater than 3.5kw. Prior to doing anything we evaluated the electricity requirements and have been advised by a number of reputable aircon companies that prior to doing anything, we need to upgrade our supply from 1-phase to 3-phase. This adds significant cost to the job and I was wondering if it is actually required. Is it a categoric YES? Or can we get by if we are disciplined with our use of the aircons (ie. making sure that nothing else is running at the time etc), or is this irrelevant? Seems to be very difficult to get truly independent, objective advice from the aircon salespeople. ps. we have a safety switch and have not had a single overload problem... even with washing maching, dishwasher, tumbledryer, plasma running at the same time, so capacity seems fine. All information is appreciated. Re: Electricity requirements for Aircon 2Nov 15, 2010 4:07 pm G'day vegasbaby. Where in the country are you? Reason I ask is some places have 45, 63, 80, 100 or 125 amp single phase supplies to the home depending on the age of the dwelling and your location. 63 and 80 amp are the most common. Re: Electricity requirements for Aircon 3Nov 15, 2010 5:00 pm Hi, Not a given, as in Sydney here we had 5 such room units put in without the need for multi-phase. The installer's sparkie mentioned the word "diversity" and said that in the extreme, if we turned EVERYTHING on for hours, we might get a breaker tripping, but we don't use them that way. There never has been a problem. However, I don't know what overall single phase capacity we started with. Cheers Re: Electricity requirements for Aircon 4Nov 15, 2010 5:10 pm I would say the reason why you would, or should I say the power company would want you to have multiple phases is for load balancing reasons. See when the power company provides power to customers they try to match the loads on each of the 3 phases they supply into the street so that they are more or less equal. If one home has the capability of using a disproportionate amount then their phase balancing equations go out the window. So each power company would have rules about what you can and cannot have and from that determine the correct number of phases you require. So I would suggest that the OP would be best off calling their local electricity company and find out what the specific rules are relating to their area, as each company will be different. Re: Electricity requirements for Aircon 5Nov 15, 2010 5:15 pm GeoffW1 Hi, Not a given, as in Sydney here we had 5 such room units put in without the need for multi-phase. The installer's sparkie mentioned the word "diversity" and said that in the extreme, if we turned EVERYTHING on for hours, we might get a breaker tripping, but we don't use them that way. There never has been a problem. However, I don't know what overall single phase capacity we started with. Cheers Your sparkie was ****** to you. Breakers do not trip if you run things for hours. Breakers trip when you exceed the current load for the breaker protecting the circuit. The most common time for this is at turn on, as all equipment has a momentary rush of current that will exceed the breakers rating, though if the circuit is designed properly this isn't an issue. But as I said there is nothing that will trip a breaker by running for hours. Re: Electricity requirements for Aircon 6Nov 15, 2010 5:35 pm GeoffW1 The installer's sparkie mentioned the word "diversity" and said that in the extreme, if we turned EVERYTHING on for hours, we might get a breaker tripping, but we don't use them that way. There never has been a problem. Sounds like the installers sparkie is a goose. No such term as "diversity" for this type of installation, what he is gambling on is the fact that all units won't be running and trying to start at the same time.What should of happened is the "maximum demand" as per AS3000:2007 A1 table C1 should of been used to determine the maximum demand for the units, then the installation planned from there. To design a system that might "trip a breaker" comes down to poor planning and installation, you should be able to run all units for days on end without the breaker tripping. A circuit breaker should only have to carry a maximum of 80% of its rated capacity in normal use, anymore increases the chance of tripping due to the combination of thermal and magnetic characterisitics of the breaker. GeoffW1 Cheers Not a drama. Glad to help. Re: Electricity requirements for Aircon 7Nov 16, 2010 7:50 am E1109 Where in the country are you? We're in Sydney, on the lower nth shore. House is about 30yrs old. It is down a private driveway which we share with another 10 or so houses. Electricity cables run from the main street under the length of the driveway. There is a junction manhole opposite our house - I guess the cables run from there into our house. All underground though so difficult for a layman like me to see anything. Other houses down the driveway have 3-phase power and most seem to have Aircon. I guess the previous owner of our place didn't need/want it. We have a couple of young kids at home, so the plan is to run 2 of aircons for a couple hours during the day whilst they sleep, and then all 3 on the occassional hot balmy night whilst we sleep. We spend the majority of time downstairs in the living area of the house and we don't need aircon there at all. Re: Electricity requirements for Aircon 9Nov 16, 2010 8:56 am dyen12 We had to put in 3 phase power for our house but we have put in ducted aircond a large unit. Also it was an old house - which had to service the pool as well. Sounds very similar to the original reqirements we had. But the prices came in way above our budget. Things have changed now... we are 1) getting rid of the pool and 2) getting 3 individual split systems The unit normally clips into a metal plate screwed to the wall, either plate is not flush, or unit not hooked in and could be hanging from the pipes partly, either might… 2 15786 retail its around double the price of a similar sized actron/dakin system from memory, They are excellent systems though. But with how builder gouge on AC/heating, you… 4 13772 This was on google. Development controls 2.3.1 Front setback D1 New buildings within residential areas shall adhere to a front building line, which is 5.5-6m to the… 1 3663 |