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  1. #1
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    Default Electrical outlet allowance

    I am in a once in a life time situation to build my dream shed. it will be steel shed about 11m x 20m. There will be an office and the dust collector at the back, then about half will be for woodwork and then the front 6.5m x 11m will be for automotive, metalwork, garden bits, etc.
    I want to be able to run some 3 phase machines in the woodwork area. Not sure that is really necessary in the front section. But might need some 15amp circuits for a hoist, welder in there or something.

    I'm not sure I can afford to line the entire thing but the idea is to line most of it with ply, melamine, whatever. Then the electrical feed to be put in conduit above or over the panels. basically exposed (but in conduit of course). This to to make is relative easy to add or remove outlets over the years ahead.

    I don't have a layout plan for the woodwork area. Well I suppose I have some ideas but the concept is to make it flexible so that I can move things around as the years go by.

    Now my question is how often to place outlets along the walls and overhead? As in, how far to space them apart? How many 3 phase? How many 15Amp? I need to scope this out so I can get some quotes from electricians. I don't need the precise electrical plan just yet.

    Anyone able to guide me on this?

    I want to have LED lighting for Africa. So I should remember outlets for that as well.

    Are there other things I should consider to ask the electrician to quote for?
    My YouTube channel: https://youtu.be/2_KPRN6I9SE

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  3. #2
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    Unless you have the machines and know where you are going to put them I would wire a minimum number of 15A (eg 2) and 3P outlets (1) until you have the machines. 99% sure you will have them in the wrong place and have to move them and that costs $$.

    However, you should roughly work out and tell the sparky you want 3 phase and roughly how many 15A machines you eventually plan to have and how many you plan to run at the same time, eg DC and table saw,. Also will you have anyone else using another machine at the same time. MW wise you might want to use a plasma cutter and allow for a compressor to fire up.
    3P and 15A need their own breaker.
    This is so sparky can work out run the correct size wires to run from the house to the breaker box in the shed, how large a breaker box and how many breakers to install. The last think you want into have to get a new breaker box!

    I started out with 2 x 15A breakers and had to move one of the 15A GPOs. Have since added 3 more 15A, and a 20A . To do that I had to upgrade the breaker box ie a PITA

    Overhead outlets are the ducks nuts, as are a flying foxes with suspended 15A and 10-A GPOs. The mens shed have 2 x15A and 2 x10A in the ww section and several in the MW section. The Sparky does not need to know this and just needs to instal 10 and 15A GPOs on the top of the wall near where the flying foxes start/end

    I would suggest
    - If you use LEDs, one lighting circuit (10A) should be enough, get the sprarky to instal GPOs at the lighting points instead of hard wiring the lights. Then you can change them any time you look
    - 1 x 10A GPO circuit in the ww and one in the MW area, for the moment. Get the sparky to run the circuits around the top of lined walls wall and drop the wiring down the front of the lining so they can be changed later if needed. In terms of how many 10A? - as many as you can - for shed your size I would say not less than 20. I started out with 13 double 10A GPOs in my shed and have since added about 10 more (my shed is 1/3rd the size of yours but I do like to have everything plugged in and ready to rock and roll.)
    - 1 x 15A in the MW area, and one 15A for the DC on the WW side, and allow room for say 3 or 4 more 15A breakers in the breaker box
    - for 3P just get one outlet somewhere you think you you might use a 3P machine and allow room in the breaker box for say 3 more 3P breakers?

    Just a heads up that you don't always need 3phase to run 3Phase machines. I have no 3P to the house.shed but I run 9, 3P machines in my shed using VFDs. Sometimes it's cheaper to buy a VFD than to use 3P especially if it includes the cost of the sparky, 3P outlets and plugs. The following 3P machines; lathes, DP, mill; grinders and an extraction fan, all run from 10A GPOs, Thebelt sander, DC and band saw are also 3P and then run from 15A GPOS.

  4. #3
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    Thank you for your detailed reply Bob. Very helpful. By running everything in conduit rather than behind panels I realise it is going to be expensive. So this cost will probably limit how many I can have to start with. But in the absence of a layout plan I need something to request.

    What is a flying fox for electrical?



    Sent from my SM-G977B using Tapatalk
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  5. #4
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    Quote Originally Posted by DaveVman View Post

    What is a flying fox for electrical?

    Sent from my SM-G977B using Tapatalk
    In the absence of a better explanation, I believe it is a overhead power point/s that run along a suspended cable.

    Overhead power points are very useful. I have 5 in my 6metre by 6 metre double garage/workshop.
    Tom

    "It's good enough" is low aim

  6. #5
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    For what it's worth, whilst I have a rough machine layout, I am still putting in *plenty* of power points.

    Like you, I have a one-time chance to build this, and I want to get this as flexible as I can, because needs change over time. I am effectively putting in a double 15A GPO every (roughly) 2 metres, except where I know more will be needed.

    My space is about 6.5 x 6.5 metres, so with that in mind, I am planning on everything being mobile, and thus moving machinery to a particular location in order to use it.

    This means that my extraction plan for the heavier machinery (TS, Bandsaw, Planer/thicknesser) becomes relatively simple, and very short.

    Other machines that can use mobile extraction may then be used in other locations around the shop (e.g. Festool sander with extractor).

    In this post: Midnight's Shed you can see one wall, where we have run the electrical cables down to the waist-high power point locations. These run inside the wall for neatness and safety, inside a 25mm conduit. Behind the plywood lining is a spark box, also for safety. The runs of cables along the top will be placed in a 50 x 75 mm Aussie Duct (I would strongly encourage this as opposed to plain conduit, as you can open Aussie Duct back up at a later date to work on, or add cables) and then be run to the sub-board being installed in the shed.

    For what it's worth, we're using 4mm squared cable, which is quite capable of supporting a double 15A GPO. Whilst the GPO's are expensive, you can save initial cost by wiring them up with 10A GPO's (which are quite cheap), and then swap out any that need to be increased to 15A later without having to touch the cabling - i.e. the building is future-proofed to 15A at all power points). The cost of the cable is more, but is immaterial compared to the cost and hassle of having to re-run cables later.

    Hope this helps!

  7. #6
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    Quote Originally Posted by Chesand View Post
    In the absence of a better explanation, I believe it is a overhead power point/s that run along a suspended cable.

    Overhead power points are very useful. I have 5 in my 6metre by 6 metre double garage/workshop.
    That sounds good. Anyone got pictures?
    My YouTube channel: https://youtu.be/2_KPRN6I9SE

  8. #7
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    Hey Midnight, I like that idea of running 4mm2 cable but initially wring 10Amp outlets. Although the electrician might not be thrilled about having 15Amp min-breakers on circuits that are never going to get that high. I can see I need to give this more thought. I need to consider how many runs from the sub-board.

    In the pictures you linked to, I'm unclear that the top holes are for. Do the cables come down on top of the ply then go behind the ply to re-appear at waist level? Thus leaving most of the wall clear but the drops still easily accessible? Clever.
    My YouTube channel: https://youtu.be/2_KPRN6I9SE

  9. #8
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    Quote Originally Posted by Midnight Man View Post
    For what it's worth, we're using 4mm squared cable, which is quite capable of supporting a double 15A GPO. Whilst the GPO's are expensive, you can save initial cost by wiring them up with 10A GPO's (which are quite cheap), and then swap out any that need to be increased to 15A later without having to touch the cabling - i.e. the building is future-proofed to 15A at all power points). The cost of the cable is more, but is immaterial compared to the cost and hassle of having to re-run cables later.
    Technically this is not correct,, while its up to the sparky to determine projected load and decide on what GPOs that can be used on a circuit, In some cases it may not be too code, and its certainly not best practice, to willy-nilly mix and match and swap 10A for 15 A GPOs on the same circuit, even if 4mm wire is used. 15A machines are typically set up with their own circuit and breaker eg 20A; while 10A circuits typically use 16A breakers. If a 15A DC and 15A Table saw are on the same even 20A circuit the breaker is going to jump. A 15A circuit is fine on 2.5mm^2 wire, 4mm is only really needed for a 20A device.

    RE" Flying fox.
    Its very difficult to take photos of the (orange) suspended cable but here is a photo shown the flying foxes in the mens shed.
    A taut SS wire is string between two walls and a few dozen pairs of split rings (joined together) are attached to the wire. One ring is attached to the wire and the electrical cord is strung through the other and then the socket attached. The cord can then be dragged along the wire to where it is required;.
    Above.jpg

    The Mens shed has 2 x 15A cords suspended in this manner and 2 x 10A cords - works a treat.
    On the left hand side of the photo you can see (grey box on the end of conduit) one of the 3 suspended 3P sockets which the sparky installed at head height (OUCH!) is why we had to raise them us as you can see

    RE: OH outlets.
    In my own shed I have 8 over head double GPOs and 3 of these have 6-way expander boards attached. There are several other suspended expander boards but these are attached to wall sockets. Many of the double wall sockets have been replaced with 4 way GPOS or have expander boards attached - like I said I like to have lots of things plugged in and ready to go. I have one OH 15A GPO and one under floor 15A GPO.

  10. #9
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    Quote Originally Posted by DaveVman View Post
    Hey Midnight, I like that idea of running 4mm2 cable but initially wring 10Amp outlets. Although the electrician might not be thrilled about having 15Amp min-breakers on circuits that are never going to get that high. I can see I need to give this more thought. I need to consider how many runs from the sub-board.

    In the pictures you linked to, I'm unclear that the top holes are for. Do the cables come down on top of the ply then go behind the ply to re-appear at waist level? Thus leaving most of the wall clear but the drops still easily accessible? Clever.
    Hi Dave,

    Yes, you are correct. In my case, we are running a separate circuit for each power point. So, the cable begins by poking out the wall at waist level, going inside a 25mm conduit and reappearing at the top where the top row of holes are. These will then be put into Aussie Duct, and run around to the switchboard location. That work will start this weekend, so I will post an update in my shed thread, and it will become clearer.

    These Aussie Duct runs, and the holes you see will end up being above the future ceiling line, thus will be invisible normally, but I'm designing a way to access this in the future without destroying anything should the need arise to work on/add/replace a cable.

    I will note one thing - if I end up installing a 10A GPO on one of these cables, the circuit breaker will be matched to the outlet. In reality, I think that lashing out and installing 15A GPO's everywhere, with appropriate circuit breakers, is going to prove more cost effective than buying 10A now, and selectively upgrading them in the future.

    More to come in my thread in the next week or so

  11. #10
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    Quote Originally Posted by Midnight Man View Post
    I will note one thing - if I end up installing a 10A GPO on one of these cables (this is to address BobL's note), the circuit will only be circuit broken at the GPO capability (i.e. 10A, nothing greater).
    using dedicated 10A breakers to power low current devices like plug in LED bench spotlights, radio/stereo, power tool battery chargers, small exhaust fans, and most small corded power tools sounds like a waste of money to me. This is why many small 10A GPOs can legally be installed on the same circuit/breaker.

    Here is a list of things that stay plugged into 10A GPOs on one of the 3, 10A circuit in my shed (all my 10 A GPOs are on 16A breakers)

    Circuit 1:
    2 weighing balances (1kg and 10kg)
    3 power tool battery chargers
    WiFi base station
    Radio/Stereo
    MW lathes
    MW lathe coolant lube pump
    Spotlights above MW lathe
    3 corded 125mm angle grinders
    1/4HP Welding bay extractor
    Welding bay LED light
    LED Pressure sensor for Ar cylinder.
    Compressor auto water venting valve system
    1.5HP Drill press.
    Electrolysis power supply


    The second 10A circuit one has
    1HP WW lathe
    WW lathe spotlight
    DC pressure/Temp Sensor
    3 x 1HP bench grinders
    Bench grinder spot light
    1/2HP MW bandsaw
    1/8HP MW bandsaw lube coolant pump.
    Tacho for MW mill
    Temp/pre/humid Sensor for ducted compressed air line.
    TS OH Guard light
    1/4HP Exhaust fan
    Shed Humid/temp sensor.
    Dremel

    3rd 10A circuit
    Bench spotlight
    Particle counter
    Shop vac
    Horse blanket washing machine
    SWMBO's glass jewellery gear
    - diamond cutting saw
    - tumbler
    - diamond spindle ginder
    - spot light
    - her own dremel charger

    The belt sander, bandsaw, table saw, DC, compressor, all have their own 15A outlets on circuit with 20A breaker.s
    The welder/plasma (and soon a furnace) all run from a 20A outlet and 4mm circuit with a 25A breaker. - just cannot use more than one at a time.

    The machines/tool I don't keep permanently plugged in are lesser used power tools, the 10" planer thicknesser and 12" SCMS and it reflects their relatively low usage.

    This way I have most things already plugged in and ready to turn on at the flick of a switch usually with no cords on the floor.

    Unless there has been an unrelated problem (like roof leak and water dripped on/in to MW bandsaw motor) or pushing machines to hard, none of the breakers have ever tripped from current overload. I have ammeters on several machines and the mains power supply so I have a really good idea of what draws what.

    I realize that this is is just way of working. Some folks like to keep an uncluttered shed and put things away and only pull them out and plug them in when needed. Unfortunately I don't have the storage space to do this (my cupboards are already chocka) but even if I did have more cupboard space I'd still have as many powered devices as possible plugged in.

  12. #11
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    Yes I am with you about having as much plugged in and ready to go as possible. it makes a huge difference. Since I would only be running one machine at a time (excluding DC and air compressor) I don't need to go overboard.
    My YouTube channel: https://youtu.be/2_KPRN6I9SE

  13. #12
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    For true flexibility, talk to your sparky about installing steel trunking around the perimeter of your work shop. Or better yet - install it yourself and let them do the earthing, etc. Off the top of my head 50 x 50mm trunking is around $30 per 2.4M length and 100x100mm is not much more.

    trunking.jpg

    All cables run in it, so only need conduit for 'droppers' to each outlet and any where you need an outlet in the future will be quick to install, even if it's a new cable run from the sub board.

    If you're certain there will be electrical changes in the future, this is the ultimate future proofing.

  14. #13
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    Quote Originally Posted by BobL View Post
    Just a heads up that you don't always need 3phase to run 3Phase machines. I have no 3P to the house.shed but I run 9, 3P machines in my shed using VFDs. Sometimes it's cheaper to buy a VFD than to use 3P especially if it includes the cost of the sparky, 3P outlets and plugs. The following 3P machines; lathes, DP, mill; grinders and an extraction fan, all run from 10A GPOs, Thebelt sander, DC and band saw are also 3P and then run from 15A GPOS.

    And the beauty of VFDs is you can dial the rpms up and down. You want to keep your neighbours happy when you run the planer... Put it on a 3phase motor and reduce the rpms witha VFD to about 2/3s, or a single phase 1400rmp motor. The first time you fire it up, you'll ask yourself: Is it on, it's so quiet. And no difference in quality of work. If you need the grunt then you can dial it back up to 50, or even 60hz...

    I'm designing a shed now and all the machines will, if possible, be on 3phase and VFDs.

  15. #14
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    I don't know what sizes panels, such as plywood, are over in Oz; but, if you do wind up running outlets along the wall, consider some set a couple of inches higher than the width of a standard panel, so that you're not trying to figure out how to plug in a tool in an outlet hidden behind the stack of plywood you leaned against the wall.

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