Thread: 3 Phase setup

Lighting is all single phase....The only bit you have to work out is where you want the 3 phase power points..

Couple of questions, do you have 3 phase at the house? If so just have the sparky run 3 phase to the shed and split you power circuits over the 3 phases. You only need to add 3 phase outlets as you need them if you don't want to pay for them now.
If you don't have 3 phase power to the house already but intend to get it in the future, run a 3 phase cable but only use two cores for single phase. It's only a matter of connecting the other cores into the sub board when you get the 3 phase power on. I should say have your sparky connect them when the 3 phase power is connected to the house.
If you intend to convert to 3 phase quickly it may be cheaper to get the sparky to put in some 3 phase outlets now instead of getting him back.
Don't forget, if there are no photos, it didn't happen

Thankyou gentlemen for your replies.............the situation is the new power line runs close to my house from a side street and that will allow me to connect to 3 phase when the proper connections are installed and then run it to my shed through one of these new fangled meter boards that allow the power company to tell when I turn the plasma on and shut it down remotely if I watch the adult Chanel too much!!. The sparky said as he had to run a new line to the shed anyway, and will only need about 4 meters to run the mains line for the 3 phase connection from the pole to the main board.....he just has to change the connection to the house and the pole for 3 phase which is easier for him to do now than later. I tend to agree.

My query was in relation to what sort of trip and circuit breaks would I need at the shed end as I don't want to upset the domestic manager when I run too many motors while she has the chook in the oven No doubt my sparky will do the maths with resistance and amps on what I run etc but I was hoping for some suggestions as to what works best with the setup I intend....ie multiple sockets, separate lines or boards with every appliance hardwired etc.......my electrical knowledge stretches to 3/5 of 5/8 etc...so that's why I am paying a sparky.........just want to be able to tell him what I want..

changing motors to 3 phase is not going to work out a good deal .so get some outlets where the new machines go , you need to know what size the motors will be to get them wired correctly, most home machines are under 2.2kw or 3 hp , and run on singe phase but over this 3phase is the go . you need to specify what how big and where and it becomes easy cheers Bob

As you will be running 3-phase to the shed, and currently don't have any 3-phase machines, I suppose it's a matter of deciding on how many 3-phase machines you will possibly end up with so that you can install a sub-board large enough to accommodate all the breakers.

In my experience of industrial workshops, each 3-phase machine/outlet has its own breaker and its cheaper to hardwire machines, albeit that it gives you no flexibility to plug in other machinery into a single line.

I suppose you may eventually end up with a 3-phase lathe, mill, grinder and maybe one other? I'd hardwire the lathe and mill and have a outlet for the grinder so that you have some flexibility to easily plug in other gear.

Therefore, I'd install a board that will allow for 3 or 4 single phase breakers (1 or 2 10A, 1x15A, 1xlighting) and 3 or 4 3-phase breakers.

You don't have to have the breakers installed right now, you just need to ensure that the wiring to the board will carry the eventual total current draw, and that the board has enough space for all the breakers. As to total current draw, check out the power specifications of the machines you are likely to own in the future and then you will have some idea of the total likely current draw. Hope this helps.

Just a few thoughts on your issue.
1/ There are quite a few variations of 3 phase plugs and power points. 10A 15A & 20A all with 4 or 5 pins. If you buy the one type from new (expensive) then you will be OK, however if you pick them up second hand you will find possible incompatability issues. For example 10 and 15 A plugs and power points have a keyway location and 20A have a flat section at the bottom. This means you can fit a 10 and 15A plug in a 20A socket but not vica-versa this stops you overloading the system. Then there is the 4/5 pin issue. My recommendation, if practical, would be to use 20A, 5 pin outlets and wiring, then every other combination of plug is covered.
2/ Have the electrician instal the submains board near the main exit so you can turn of the main switch as you leave after each shed session. This way you know for certain that everything in the shed is turned off, including that overlooked soldering iron etc.
3/ Permanent connection of machines allows for the correct motor protection to be installed but has an interesting side issue. If you or someone else sells the house then the machines could be classified as part of the PC items such as the stove. It may be an urban myth but I have heard of a house buyer enforcing this clause of a contract and getting machines that the seller thought were his.
4/ Make sure the electrician wires all of the 3 phases the same in each power point, if he does not some machine motors will go in different directions depending on which power point they are plugged into.
My 2 cents worth, hope it helps, regards, MM.

Hi barkersegg,
In answering your question you have there are a number of variable as mentioned by the other postings.
I suggest you go to your local Electrical Wholesaller and pickup a copy of the NHP 2009/10 CPB Pocket Book Catalogue.
Have a look in section 2 this will give you an idea on the Load Centers you can get, then you can decide on one, two or three row unit, this will depend on how many Breakers you will want. If you work on one Breaker per outlet then you multiply the number of Breakers x width to see what size Load Center.
For the Outlets as mentioned by Metalman you need to look at what ratings they will need to be, as many of us change things arround in the Workshops look at settling on say 20Amp Outlets as a standard, most equipment wont need to draw more than this. If you think you may then look at a 30Amp Outlet.
When choosing the Outlets run 3 Phase Neutral & Earth to each and settle on a brand type, the best would be Clipsal as they are very common.
From this your Electrican can calculate what the load will be and size the Breakers, also consider what type Curve the Breakers need to be as normal Breakers are a C Type Curve but D Type Curve Breakers are best suited for Motor applications.
Also consider installing RCD's on your Single Phase Outlets as protection. Also look at a special outlet for your welder, Isolate this from other items in the Load Center as they can cause transients etc. To finish make sure that the Workshop Power is run totally separate from your house Circut as noise harmonics etc can effect house hold items.

I hope this has been of help.
Regards,
Keith.

Thanks again gents.........you have given me plenty of info so I can at least understand what my sparkie is talking about now and the way I would prefer it to be wired up....some really useful suggestions - appreciate the replies.................Lee

one of the MOST important considerations is the main isolation switch capacity, and wire running from the main board to your shed sub-board.

When I got my shed connected to 3-phase (I had 3 phase at the main meter box, but only single to the shed), I made sure that the wiring and main isolation switch had the capacity to do all I could ever want.
Standard lighting and power in most sheds - single phase 10 Amp.
3 separate 3-phase machines in my shed - 3-phase 10 Amp each
main wiring capacity - 80Amp per phase.
Main isolation switch - 63Amp per phase RCD protected.

basically - I could run every single machine at the same time, as well as all lights, dust extraction (I'm a woody), air compressor, and STILL not trip the main circuit.
I wouldn't want them all going for very long, or my power bill would be off the scale, BUT the point is, I'm not limited in what I can wire up in the shed.

If you only plan for 2 x 3-phase machines, and 1 light circuit, and that's what he wires up, you'll cry when that next purchase requires a major shed re-wiring because it wasn't planned for in advance.

if the main wiring can handle heaps of circuits, but you only use a few now, then adding more later is easy. the other way round though - not so much fun.

PS don't bother putting 3-phase power points in until you have a machine that can use them. As has been mentioned, each machine typically will have it's own dedicated power socket rated to suit that machine. There's no one-size fits all outlet.

PPS. already mentioned - get your sub-board mounted near your exit point of the shed, so you can shut down everything with one switch as you leave. A definite safety feature - prevents kids (if you have them) turning tools on unnoticed, prevents you leaving soldering irons etc on, AND isolates all your tools from electrical storms.

In the past I've had a lightning strike kill a couple of VFD controllers on machinery. Now - when I see lightning on the horizon, or a storm warning on the TV - I just run out to the shed to double check the main isolation switch is off, and voila! No problems for my machinery if lightning does strike the TV antenna or a nearby power pole.

Every appliance in my house might fry - but my precious machiney - safe and sound!

The Main Switch typically used in Load Centers is either 160A or 250A 3 pole 415 V AC, I would suggest the 250A Switch.
For protection against Transients caused by Lightning there are devices that can help, I attach some information for consideration.

Regards,
Keith.

When I had the power done in my shed I also had a 4 wire meter installed so that I can accurately put the power costs of the shed in my accounts. Saves on missing out or making percentage sq metre calculations. I was lucky enough to come across one that was going in the bin at a job I was doing, but I was going to do it anyway. II think at the time it was only about $300.00 or $400.00 for the meter.

My 2c worth.

If you are not in a screaming rush for the power you can save a lot of money by buying things like 3 phase plugs and sockets, even your sub board and breakers used.

When I did my old shed a couple of years ago, the eleco told me what I had to get and I picked up a lot of it from e-bay and also from a local building demolition yard. From there I bought a complete meter box that had an almost new sub board in it, complete with about 12 breakers for $50.
Once you start buying 3 phase stuff the price goes through the roof.

regards
bollie7

When my workshop was wired for three phase several years ago, the electrician installed two 32 amp circuits each feeding two 20 amp socket outlets. This setup has served me well, with the four outlets strategically placed around the workshop.
The relavent Standard at the time was AS 3000-1986, and I would be suprised if this setup is not allowed by the current version of AS/NZ 3000. I suggest you ask your electrician about this option; clause 2.11.1.2 was the applicable section of the Standard.

Regards,
Chas.