Installing energy meter (Wattson) with E7

[klanger]

I'm trying to work out how to install energy meter.

I have economy 7 with 'Multirate Single Phase Watt Hour Meter' and radio teleswitch (see pics). I have one fuse board and two switched fuses (I think). I can't work out where I need to put the sensors. Pics show two red cables and one black (along with a big mess of other grey cables). Can sensor be installed before radio teleswitch? If so where?

Just for info, I have two storage heaters (was originally three... I removed one) on economy 7... as far as I'm aware all other appliances/sockets work during day.

Any help would be appreciated... thanks.

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[aptsys]

Is there just one sensor? If so, you can clip it round the wire furthest on the right on the meter.

 

[klanger]

Is there just one sensor? If so, you can clip it round the wire furthest on the right on the meter.

I've got two sensors. I was led to believe (by company that make the product) that I'd need two.

Am I right in thinking that if I clipped one sensor round right hand wire (as suggested) that would detect all elec used (even during night rate) but not differentiate between the two rates?

As I have two sensors, is there a 'cleverer' way of doing it?

 

[Steve]

On the radio teleswitch, put one sensor on the far left wire. This will tell you total consumption.

Put the other sensor on the far right wire. This will give you storage heater / off peak only loading consumption.

I dont think theres another way of doing it. Theres no way you can measure the total off peak consumption using these sensors alone since the main supply also goes to off peak and thats the second thick wire from the left on the teleswitch.

If the sensors are connected to logging device, you can work out if your eco7 tarrif is worthwhile. You'll know exactly how much you spend heating (though it sounds like you have other sources of heat now?).

Can you post a picture of the service head (to the right i think) - where does the second wire from the right go, from the teleswitch?

 

[BS3036]

It might be worth asking the manufacturer specifically whether the software provided can work out what power is used at what price rate. Their web site is fairly vague, even though they refer to Economy 7 in their FAQs.

In theory, if you could tell the machine what the probes were connected to, it should be able to distinguish the amount used at each rate. But the user manual doesn't hint at that.

 

[Steve]

In theory, if you could tell the machine what the probes were connected to, it should be able to distinguish the amount used at each rate. But the user manual doesn't hint at that.

Not with his setup, unless it took a direct output from the teleswitch that told the software then E7 was live. Then again, the software could use the heater tails to tell that E7 was live. But how would it know that E7 had gone off? Since the heaters cycle on and off with 'stats. A tricky one.

 

[klanger]

The software can distinguish between day and night rates (you just programme it to tell it when those particular times are). So, as long as the sensor tells me total consumption I'll be okay.

Here is overview photo just in case there's anything amiss.

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[BS3036]

Yes you're right, of course, Steve. My notion would need some sort of measurable base load on the heater circuit, which isn't likely.

klanger: it sounds like you have a reasonably close solution. It's a shame that the manufacturer doesn't seem to understand E7 wiring, as it would have saved you a sensor. Though I suppose you get to find out how much you spend on the heating, as a separate item.

I must admit to being fascinated by measurement of real house loads, as it rarely seems to equate to expectations. I'd love to see some histograms over a weeks usage.

As an aside, we measured earth leakage current in my son's room a couple of weeks ago with 4 PC's, 3 monitors, a DVD recorder, a TV, a video projector, and 4 games consoles, plus misc networking equipment all running at the same time, and got 5mA.

 

[klanger]

Thanks for the help.

I'd be quite happy to put up some data in the coming weeks.

According to my calcs the machine will pay for itself in 6 to 12 months.

I could have bought a cheaper model of course... but its a beautiful bit of kit and I'm a sucker for good design (hence 24 inch iMac that I'm using!), also I believe it's currently the only model on the market that allows you to upload to PC/Mac and store data... a must in my opinion.

Thanks again.