Question for the Sparkies : 3 phase Power Meters

[Ed.]

G'Day all, I am about to start build a new steel shed on my property and would like a power meter in the sub-board to keep track of how much power I am using on the 3 phase circuit, mainly for curiosity purposes. I am looking at several meters but the specs are a bit foreign to me, for the record I will not be doing the wiring, I am just buying all the bits so after the earthworks are finished I can get the sparky to proceed without waiting for all the parts.

The power supply over where I am is 234-240V single phase 50hz and when combined it ends up about 415V 3 Phase. The thing is that most of these units here are slightly different and my sparky is on holidays for the next month. The specs in question are as follows:

3x5(80)A
3x5(100)A I assume that the "set" and "turn" have something to do with the RS-485 interface (which I don't need)
3x5(100)A
3x10(60)A
3x20(80)A

The biggest welder I have is a 27Kva unit, but as I don't run it anywhere near its full power, I will assume it will use less than half of its rated max draw. So what do the specs mean, just trying to work out which one to get! The cable to the shed is 25mm 4C+E and the shed will have a 40A main circuit breaker. The cable is way overkill but it came up much cheaper than the 16mm I had intended to buy, looking on the bright side there will be no voltage drop, the welder runs quite happily on a 32A MCB. Any thoughts or recommendations on these meters?

Cheers
Ed.

 

[Ed.]

Oh well, no replys, not to worry, I ordered the 3rd one, hopefully my sparky will approve it when he gets back from holidays. It should arrive in a month or so and I will see then if I have wasted my money on it or not.
Cheers
Ed.

 

[fizzy]

Oh well, no replys, not to worry, I ordered the 3rd one, hopefully my sparky will approve it when he gets back from holidays. It should arrive in a month or so and I will see then if I have wasted my money on it or not.
Cheers
Ed.

Patience is a virtue

 

[Barking Mat]

If it's just to see how much leccy your using, it's all much of a muchness.

 

[JMS1972]

A bit late but considering the amount of power involved and the fact it's always on, I'd be looking for something from a reputable supplier with proper CE marking (not China Export!)

 

[Barking Mat]

I'd just stick an ampimetric clamp meter, to give me a vague Idea, which machine pulls what.

Still got to pay the leccy bill at the end of the day.

 

[brightspark]

says 80 amp that will be each phase so well big enough just make sure you have a 3 phase and neutral supply the meter wont register if there isnt a neutral

 

[Ed.]

These meters all have the 3 phase L and N on them. The local ones are 2 to 3 times the price and no stock available anyway. The one I used in my old house worked well but couldn't remember which one I bought, unfortunately I have a stack of other items to order as we are building a house as well so can't spend too much time on something like this due to the long delivery time, the costs here in Oz are sky rocketing too, our house build costs have risen about 80K$ in the last 10 weeks, so trying to get as much stuff as possible whilst it is still reasonable and save where I can. Best deal I have got was the 25mm 4C+E cable, it ended up $750 for 95m old stock instead of the current $2800, the more it costs to build the house, the smaller the house gets .
The most annoying thing is trying to find information, every time you ring a company, you get "due to the Co-Vid virus impacting our business we have extended long delays in answering your call, and your call is important to us so please stay on the line and we will get to you as soon as we can". Meanwhile an hour goes by whilst your hanging on and very little other work gets done. Then the next call you make and repeat the process!! arrrg!!

 

[Dave-sparks]

Just get a distribution board with a built in meter, no point messing around adding an extra meter external to it. It will come with all of the current transformers, correct fuses etc in a simple plug and play format.

 

[Ed.]

The situation on our block is the shed will be at the front of the block and the house at the back to get ocean views, my problem is that I have to get a builders pole put in near the shed so I can actually weld up the shed, but the builder needs to access power to build the house. So the sparky will connect up a builders pole with that proper meter in a smaller Distribution box next to where the shed will be and then we need to run the cable to a larger box at the house as all the house wiring, 3 phase solar connection and aircon, will be in that one, and I will just connect a sub-board off the first box to give me the single phase and 3 phase power to weld the shed up and also to wire it up. The main problem is the bock has about a 30 degree incline and has rock under the topsoil, as we need to terrace the block, that will put the ground level closer to the rock, so the earth works and trenching for the laying the cable into it is going to cost heaps so hoping to do it all from just one trench.

 

[Matrixx]

there are 2 types 3ph 3 wire & 3ph 4 wire. if you have a neutral it will be 4 wire.
kWh meters will only tell you the total consumption, for the actual Amps/kW you would need a kW meter, or a multifunctional one which will tell you Amps, kW , pf, Volts , Hz etc.

 

[Ed.]

Mine is a 4 wire setup, and as I said earlier, the meter will be only for my information use only and just to give me an idea of how much electricity I am using in the shed as opposed to the house use. I don't think it will be much as I tend to do a project and then nothing for months on end, till the next one. I also have a single phase meter which will also show my usage on using grinders, drills, sanding machines etc. In fact, the actual meters probably cost way more than all the electricity consumption that I will use, but still it is interesting just to know. Plus I tend to only work during the day and so the solar panels should negate most, if not all of the cost of the electricity anyway.