Multiple fuse box within building

Good evening, 

 

I am planning to monitor the electrical consumption of a building in which there is one main fuse box and four to five secondary ones.

My purpose is to break down the consumption by rooms but I did not find a clear explanation of 

> How many sensor can I connect to one main Arduino?

> Is it possible to connect all of the transmitter nodes through ethernet? The house in question doesn't use Wifi.

Thank you in advance for your kind guidance, 

 

DRL

Robert Wall's picture

Re: Multiple fuse box within building

"How many sensor can I connect to one main Arduino?"

As many as there are analogue inputs to your Arduino. How many is sensible depends on how you want to monitor. If 'discrete sampling' is OK for you, then the realistic limit is probably around 25. If you want 'continuous' monitoring, then five is the realistic limit.

"Is it possible to connect all of the transmitter nodes through ethernet? The house in question doesn't use Wifi."

If you use the RFM69CW radio modules on your sensor nodes, those are not WiFi. You will in addition need an emonBase, which could be an emonPi, to receive the data and connect to the Internet.

Alternatively, you could use an Arduino with Ethernet as your sensor node.

DRL's picture

Re: Multiple fuse box within building

Thank you for your reply!

If I understand correctly, one base can manage up to 25 CT sensors data in discrete sampling. 

One arduino Uno has 6 analogs in therefore I can connect up to 6 CT sensors per board?

 

The thing I want to know is to identify sources of power loss. Compared to similar building, the one I need to monitor uses up to 200% more electricity. When I break down the usage per household items, I do not reach the total used. 

Hence, would it be possible to monitor the overall consumption (continuous) as well as secondary units (discrete) in order to determine discrepancies?

Robert Wall's picture

Re: Multiple fuse box within building

"One arduino Uno has 6 analogs in therefore I can connect up to 6 CT sensors per board?"

Yes, but only if you're content to have an estimate of apparent power. If you want accurate real power readings, one of those inputs needs to be the line voltage (suitably transformed down of course), so it's 5 current plus 1 voltage.

"would it be possible to monitor the overall consumption (continuous) as well as secondary units (discrete) in order to determine discrepancies?"

Indeed it would be possible, but tricky to do both in one sketch, and there's little point. If your meter has a pulse output, it might be preferable to use that rather than measuring current and voltage.

You might like to look at the higher-powered Arduinos rather than the Uno, ones which have more analogue inputs. I'm no expert on Arduinos, there are better people around to advise you on that. Take a look here: http://boredomprojects.net/index.php/projects/home-energy-monitor

"one base can manage up to 25 CT sensors data in discrete sampling."
That's a guess based on the amount of time one channel takes to sample (200 ms) and how often you will want to sample (say every 10 s), leaving plenty of time for sending the data out and for serial monitoring. It's not a hard limit. If you do 25 channels in blocks of 5 (i.e. 5 Unos) and use the radios to communicate, then it's probably getting close to the point where it is probable that two will be transmitting at the same time and the data will be corrupted. It probably won't be a problem if they're all using Ethernet.

Which country are you in, and what's the mains electricity supply?

DRL's picture

Re: Multiple fuse box within building

Thank you for your kind answers and my apologie for the delay.

I am from Belgium and the main electricity supply is three phases.

Robert Wall's picture

Re: Multiple fuse box within building

In that case, if you want accurate voltage readings, you should have one voltage input from each phase, but if the three phases are closely balanced, then you might have sufficient accuracy if you use the three-phase sketch. You might also consider using one Arduino per phase.

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