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  1. #1
    Join Date
    Mar 2017
    Location
    Brisbane
    Posts
    245

    Default Recommended elctrician for installing 3PH-Logan area? Any tips? How many amps?

    Hey fellas

    As the title suggests I need 3 phase installed at my property. Can anyone recommend a good person or mob in SE QLD that services Logan that won't rip me off? Ive heard some people get quotes from people from 2500 to 7500 for the same property.

    Is there anything I can do or should watch out for?

    It's a pretty simple little 3 bedroom house with overhead power that looks like it's 3 phase. I just bought the property so I dont know yet if it's got 3 wires going to the board or not, and it's tenanted for another month or so so it will be hard for me to see.

    I'm getting the 3 phase as I have a Optimum F80 and 'little' cnc lathe (3-4 tonnes or so), which is rated about 5kw on the name plate. More machines will follow or replace these eventually. Not sure how many amps I should be getting.

    Thanks.

  2. #2
    Join Date
    Mar 2011
    Location
    Southern Flinders Ranges
    Posts
    1,536

    Default

    Energex or whatever it was SEQEB became should be able to tell you what the consumer mains going into the property is if you call them.

  3. #3
    Join Date
    Nov 2016
    Location
    Gulfview Heights, Adelaide
    Posts
    83

    Default

    I have a 32 amp 3 phase supply running to my workshop. I only use one large machine at a time (eg. welder, milling machine).
    The electrical service at the house main switchboard is 80amp. I also have a 3 phase air conditioner in the house.
    I have never needed anything more.

    You can most likely run a larger capacity from house to workshop, but the cable costs can add up if it is a reasonable distance.

    Hope this helps.
    Paul.

  4. #4
    Join Date
    Mar 2014
    Location
    South of Adelaide
    Posts
    1,225

    Default

    My work has a 150amp supply, and we have had 3 VMC's running, 2 large (600mm + swing) lathes running +compressor, lights admin, and still had plenty of spare power.

  5. #5
    Join Date
    Nov 2017
    Location
    Geelong, Australia
    Age
    57
    Posts
    2,651

    Default

    To work out how big a supply you need, a decent sparky will run through the gear that you want to run in the shed, and also the big power consumers in the house such as A/C, electric oven and/or HWS etc.
    Part of the shed requirement will be whether the machines will be running just one at the same time, or multiple machines at once.
    If you're running CNC machines its feasible that they could be running at the same time.
    Also keep in mind that even if you intend to only run one CNC machine at a time that other manual equipment that consume a fair bit of power such as air compressor, welder, plasma cutter etc could potentially be running.
    I always thought because I only have manual machines - that as long as the power supply could cope with the biggest one then I'd be OK.
    Then I got a decent plasma cutter, and obviously the compressor has to be running at the same time. If I decide to make a CNC plasma table, then it could potentially be running in the background while I'm something else. Suddenly I'm in the situation of running multiple machines - potentially at full power.

    Machines and motors usually have the voltage and maximum current draw on their nameplates.
    I've got a 5.5kw motor in the shed, and its plate says 415v and 10.4A current. I'd expect your CNC lathe to be similar.

    Here in VIC (I assume its similar in other states), once your sparky has worked out what your maximum demand is, then you can apply to the power distributor (not the retailer) to see if they can supply it, and what its going to cost you for them to do it.
    That's just for the infrastructure side to get it to your switchboard/boundary, and what they actually offer you and how much it will cost will depend on what infrastructure they already have near you property.
    If there's 3ph on the pole out the front and their transformers etc have enough spare capacity for what you've requested then the cost will be substantially lower than if they need to upgrade a transformer just for your supply, or the nearest 3ph supply is 400m down the road (as is currently the case at my place).
    It could be a case of they can offer you 50A for minimal cost, but if you definitely need 64A then they may need to start upgrading things (and you're going to wear a fair bit if not all of that cost)

    Then there are the costs for everything on your property that your sparky will look after.
    Supply cables, installation, trenching (if required), potential main or sub switchboard upgrades if the current boards are too small to take the 3ph and extra breakers etc, then finally the actual cabling and outlets in the shed.
    As you can imagine there are a huge number of variables there, so its possible that Joe down the road got 3ph to his workshop for $2K because the main switchboard is on the wall of the workshop, he only wanted 2 10A outlets, and its only 10m to the pole/pit in the street.
    Fred around the corner was going to have to spend $30K because he's further away from the pole and his workshop is a separate building at the back of the property and needs to be trenched and have a larger cable to keep the voltage drop within limits at the shed etc etc.

    If you don't already have a sparky you're probably best to call a couple of local ones and have a chat for a start. Ask them if its the sort of work they normally do, and if its not (or even if they don't seem interested) just move on and find someone else.
    Since its your property and sounds like you're planning to be there for a while and will likely be replacing/upgrading machines - having a good working relationship with a local sparky can only be a good thing.

    When it comes to getting quotes, make sure you're comparing apples with apples. Ask what size feed cable is being run to your workshop, and whether it can cope with more power later on if need be, or if its already pretty much on the limit for that size. If your budget is tight try not to cut costs on that supply, as it will be a major PITA to upgrade later. Dig the trench yourself or reduce the number of outlets in the workshop etc to reduce cost if you have to - but try not to skimp on the supply cable. If you absolutely have to skimp, at least make sure if you're trenching that the conduit will take the larger cable later if you need to.
    I'm not a sparky but deal with them regularly at work and often see situations where someone chose the budget quote and then a year down the track has to basically redo the lot because they want to add/upgrade something and what was installed first time can't cope with anything extra.

    Apologies if I've waffled on a bit, but you need to be aware you're effectively buying a custom made system not a commodity item and the costs are very specific to the property and what you want/need.

    Steve

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