How do I tell if I have 3 phase power?

[Trav]

Hi all

I bought a centameter (see www.centameter.com.au for details). Its a device that measures power consumption.

When I went to install it, I seem to have three cables coming from the meter to the power board. All three wires connect near the main switch on the board - one to the switch itself, and two to 'blank' circuits immediately next to the main switch. The photos show you what I mean.

I've got a 15A GPO immediately beneath the circuit board, but I don't seem to have any other different power points anywhere.

Does this mean I have three phase power? Or is it just wishful thinking.

Also, a sparkie mentioned just after we bought the house that this was an industrial/commercial power board and that it already has residual current device installed. Is that the creamy box at the bottom right hand corner of the circuit box?

Thanks

Trav

[journeyman Mick]

I seriously doubt you have 3 phase, unless that's some type of ganged switch. What sort of meter do you have? The box down the bottom is a RCD.

Mick

[boban]

On that first photo, it looks as though he has three phases going into the main switch. Only two phases seem to be in use. In my old shed, I have a single visible lever switch that switches all three phases.

How many wires come into your place and how many meters do you have? If you have four wires coming in, then you have three phases. Three active and one neutral.

All you have to do is look for the source wires. They are the ones that go to the main switch.

Show us a picture inside your meter box.

[nev25]

It looks to me that you do have 3 Phase
I'm a bit curious about the switch board and where it is and why so many circuits.
If you never stated that its on your house I would have said it was a town hall or something Commercial

Without being there and tracing wires I cannot tell what that RCD is protecting.
I would get a sparkie in to take a look and to get him to install the Centameter

He will also be able to look at the mains box to tell if you have 3 phase.

BTW do you realize by taking the cover off the switchboard you have broken the law and could be subject to prosecution

[Sideshow]

You have a three phase main switch - incoming supply is connected at the bottom, outgoing circuits feed out from the top. All three phases appear to be in use - two cables feed the copper busbars to the right of the board and the third phase is directly connected to the left most copper busbar (you can see it connect into the main switch).

A certain way to tell if you have three phase is to look at the supply authority's meter - three phase meters are easily distinguished from single phase. Post a photo if you're not sure. Alternatively, check where the supply connects to your house - three fuses = three phase. This only works for overhead supply though.

I can't make out the writing on the escutcheon plate, but from all appearances you don't have any three phase outlets - all the breakers appear to be single phase.

In short, this is a good thing - installation of three phase outlets etc would be relatively straightforward so long as your mains have the capacity to carry the extra load. A sparky will be able to determine what's what. You appear to have the physical capacity to instal three phase circuit breaker in the lower panel.

Nev25 - are you sure that removing the escutcheon is illegal? I wasn't aware of that. - Is that AS3000, or other?

Cheers.

[patty]

All i can say is that is a mess obviously ole mate who installed has never used cable ties in his life the unit down the bottom may be an rcd but it could also be an rcbo combination rcd/circuit breaker! be very careful of what you are doing there you have taken the escutcheon cover off the Sub-board and have exposed "live parts" these are Moulded Case Circuit breakers and a triple pole main switch looks like old school quicklag or Heinman Breakers strange to be in a residential apllication or is this a block of flats? Still a mess though!

[boban]

I see what you are saying Sideshow.

Are those copper busbars still commonly used? I haven't ever seen them before. I thought they just used 2.5mm2 to feed the circuits.

Given that I am not a sparky, I am not surprised.

[Barry_White]

I think you will find that they are Quicklag circuit breakers and if they are the supply comes into the top of the circuit breaker.

If you trace the wires and the busbars on the top you would find each bank on the CB are fed by a different cable.

Then if you look at the Triple pole CB you can see where it is fed from the different feeds and the last bank on the left is feeding the right pole on the triple pole CB with the busbar.

So that means all poles on the Triple CB are in use.

So any sparky's would realize that the tops of the CB's are all connected in banks so that is where the feed is going in. Also all the cables at the top are larger than the cables coming out of the bottom of the CB's which means some of them are probably light circuits.

So Trav you must have something in your house that is running three phase but as the others have said get a sparky to set it up and in compliance with the forum no further advice will be given.

[Sideshow]

I think you will find that they are Quicklag circuit breakers and if they are the supply comes into the top of the circuit breaker.

If you trace the wires and the busbars on the top you would find each bank on the CB are fed by a different cable.

Then if you look at the Triple pole CB you can see where it is fed from the different feeds and the last bank on the left is feeding the right pole on the triple pole CB with the busbar.

So that means all poles on the Triple CB are in use.

So any sparky's would realize that the tops of the CB's are all connected in banks so that is where the feed is going in. Also all the cables at the top are larger than the cables coming out of the bottom of the CB's which means some of them are probably light circuits.

So Trav you must have something in your house that is running three phase but as the others have said get a sparky to set it up and in compliance with the forum no further advice will be given.

I agree Mr White, this could be one interpretation - I looked at the marking on the escutcheon, which I couldn't quite make out - the single phase breakers are numbered, the three phase is not and I interpreted the label as main switch. I thought the lugged connections would probably be feeding the board below, didn't interpret these as the supply. Also, went off the size of the SDI's - that's a big current draw if it's feeding something as opposed to being a supply.

Could go either way (three phase supply main switch or three phase breaker), good example of needing a first hand look rather than going off the photos. In any case - he's definitely got three phase .

Trav - what happens when you turn off the switch on the left? Lose everything or just one piece of equipment?

[NCArcher]

Hi Trav,
Yes I'm a sparkie. Yes you have 3 phase power.
The 3 SDI (Single Double Insulated) cables come from the meter and connect to the bottom of the 3 phase main switch.
Copper bus bars connect the tops of the circuit breakers together and the individual cables run from the bottom of the CB's to the light and power circuits. You have no 3 phase outlets or equipment installed.
The 3 cables connected to the copper bus bars supply the board extension mounted under the main board.
The bus bars you have exposed by removing the cover are alive at 415V. Be very careful. I had a bit of a read about the centameter and it does not require hard wiring. However I strongly recommend that you get your friendly local sparkie to install it for you. Messing around in the switchboard is not a good idea. If it is installed incorrectly it will not work and may become a hazard by reducing the clearances required from live parts to the metal casing of the switch board. It shouldn't take more than 1/2 hr or cost more than an hours labour (assuming minimum time charge)
With the money saved on electricity consumption through the centameter it's worth paying a few dollars to have it installed properly and safely.

[boban]

The first CB looks to be marked "main switch" although it is not entirely clear. If it is, then it appears logical that the feed is from the bottom (where the wires are still coated in the TPS). From there it is coming out and feeding each bus bar. Then there seem to be lugs supplying the lower circuit bank.

Hey guys, do they still use those copper bus bars?

Edit: just wasted my time as Archer has pretty much said what I was thinking.

[patty]

Yes bob they still use insulated copper busbars pending on the installation requirements this board is an absolute disgrace!

[nev25]

Nev25 - are you sure that removing the escutcheon is illegal? I wasn't aware of that. - Is that AS3000, or other?

Yeah Ill try to find the reg when I get a chance
Its something like having to use a tool to remove a cover that will expose live conductors must be done by a qualified person


Patty looks looks a standard wiring job to me


Bit concerning what the RCD is supplying

[patty]

Patty looks looks a standard wiring job to me

All I can say is if I wired a board like that I would have had my ???? kicked I know how tight for space some of these boards are to work on and it does make it difficult to keep cables neat the phases are not clearly identifaible as far as colour coding it looks as though the conduits do not have any actual terminators entering the board just to me it comes down to pride in workmanship if you call this standad I call it sub standard!

[Trav]

Hi all

Thanks for the advice.

We're definitely getting a sparkie to install the centameter now. If it was a simple job, I was going to give it a go, but given the mess inside the box, I think we'll get a pro.

The centameter measures the magnetic current flowing through the cables to determine power use. All you need to do is clip the sensor over the insulated wires (ie don't need to remove the insulation).

I needed to work out whether it is three phase, as I need to get two more sensors (ie one for each phase).

I don't think we have any 3 phase appliances or switches in the house - the hot water or the duted heating would be the only options.

Thanks everyone for the advice. I thought I mihgt post a review of the centameter on here if anyone is interested.

Trav