I hate to look at our power bill every month. And I want to help save the planet. So I love the idea of having a home power consumption monitoring system that provides a real-time indication of how much energy you are consuming, and how much it is costing you.
There are many options out there now for devices like this. I recently discovered that some of my IBMer colleagues in the UK are having a great time hacking on the CurrentCost device. So I decided to give that one a go, knowing full well that I might have some integration problems hooking it into my house here in the US since the device is designed for UK households. The fact that there is significant community activity focused hacking/extending the device’s output very is important to me.
I sent a note to CurrentCost inquiring about how to purchase and ship to a US consumer. I received this response…
Hi Chris,
You may or may not be aware we have a very keen IBM community here in the UK, it may be due to that you have made contact?
Ordinarily we don’t ship overseas – the product, although adaptable is designed for the UK market. However, we like to support the IBM community and if you’d like to receive a unit, we would happily welcome your feedback for (possibly) altering it for your region.
If you would like to receive a unit with my compliments, please let me have a delivery address.
Kind regards
Martin Dix
Fantastic!
Yesterday the device arrived via FedEx. Thank you for including the custom data access cable!
CurrentCost device OOB
Now – I’m pretty sure that household current in UK is single phase 220v all the way to the wall sockets? My house is standard US setup around here: two phase 220V coming in, split into two single phase 110V hot buses in the power distribution box, with some circuits connecting across both buses to bring two phase 220 V to large appliances.
Question: by placing the single induction coil sensor around only one of the two mains (thick black wires feeding into the top of the breakers below) will it be able to accurately sense the power being drawn by all of the loads in the house?
I’m thinking the answer on that is no. I’m guessing it will sense the current coming on only one of the 110V buses plus the current from any 220V loads across both buses… effectively missing all of the 110V loads on the bus connected to the other main that it is not clamped to. (I’m hoping I’m wrong?)
Hi Chris, I work with these monitors, and I agree with your comments.
I’m guessing, but I think the way it should work in the US is that each 110V bus will carry the current due to its own 110V outlet load (obviously), and the current due to the 220V outlet load will appear in-phase and added to each of the 110V bus lines equally. Power factor and switch-mode wobbly waveform loads will have an effect, of course, but that’s another story.
Say we have a 110V 10-amp toaster on bus 1 and 110V 3-amp kitchen spotlight bar on bus 2. If we now turn on a 4-amp 220V cooker burner, Bus 1 will read 10 + 4 = 14A and Bus 2 will read 3 + 4 = 7A.
The Current Cost sensor can accept optional 2nd and 3rd CTs (Current Transformers) and it simply adds up the energy from each. So it should pick up correctly if you acquire an extra CT and plug it in, one on each 110V bus.
However, the European version of the sensor software uses a volts value of 240V in calculating Wattage, so in the 2 x 110V bus scenario it will send roughly double the value of the actual Watts to be displayed and output in the XML.
Does that all sound plausible?
Cheers, Chris
Dude just turn off the pool heater!