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If you search the forums, I think you will find something about a system with that many inputs, but obviously not using the ATMega 328P processor. However you can connect 4 x emonTx to one emonBase to solve your problem that way.

Hi Robert,

can you give me a hint where to look for?

I found this for somebody else a while ago: http://boredomprojects.net/index.php/projects/home-energy-monitor

Here's another multi-circuit monitoring project. This one is based on the Spark Core. (which has an STM32F103 72Mhz ARM Cortex M3 CPU) The OP intends to eventually monitor 16 circuits.

http://openenergymonitor.org/emon/node/10428

I've used up to 5 emonTX's with one emonBase (20 channels of monitoring).  I'm sure there are a few packet collisions, but it worked fine.

Hi Robert 

yes, found this one too yesterday!

thx!

Thx Bill

will have a look...

Hi JD

nice work!

how did you link them to the base?

where to read the manual you used to build your project...

Hi Hemerje,

To build project:  I followed the instructions on this site.  i.e. http://wiki.openenergymonitor.org/index.php/EmonTx_V3.4

How are they linked:  I have a bunch of EmonTx's being used at multiple sites, and when troubleshooting a power usage problem we drop in a few more EmonTX's to monitor suspicious circuits until the problem is discovered.  The only thing changed to make them work is the node number.  They are conencted using the wireless connection, even when they are right next to the emonBase.  

How to get started:  I bought the pre-built package from the OEM shop first, and spent some time understanding that one.  It would have been too much for me to jump into a big system all at once (I'm not a computer guy primarily).

Here is a pic of an enclosure with 2 emonTX's for a total of 8 CT inputs.  (One of the EmonTX's has an enclosure, the other one doesn't.  There is also a relay board and a backup battery in there, which are not required.):

Here is one installed outdoors at a ranch (only 4 inputs at this location):

Here is the dashboard for a system that has 12 inputs.  It has been in operation since November 2014:

http://data.peakmonitor.com/proto3

Nice setup and dashboard, Jeff. Looks good!

Instead of these CT's, http://shop.openenergymonitor.com/100a-max-clip-on-current-sensor-ct/ , can I use smaller micro CT's, because i dont have the big space for these big CT's in my electrical fuse box...

Something like:

http://www.brultech.com/products/ECM1240/CTRequirements/types.htm

https://www.campbellsci.com/cs11-overview

The maximum AC current I need is 16 Ampere per electrical group.

You need to make sure you have a high VA rating to develop the 1.1V rms across the burden resistor that the emonTx requires for optimum performance.

maybe: https://www.sparkfun.com/products/11005?

Fixed link - BT

According to the datasheet for the CR Magnetics CR3100 series CTs, they will develop up to 10 VAC across a burden resistor.

www.crmagnetics.com/Assets/ProductPDFs/CR3100.pdf

www.crmagnetics.com/ac-current-transformers/3100-series

Hi Robert,

do you have any experiences with smaller CT's?

No. As I said, you need a lot more volts across the burden than most modern CTs are designed for, which is often 0.333 V rms. As you increase the burden value, you increase the load on the transformer (hence the need for a bigger VA rating) but you also increase the errors. I know Robin (mk2pvrouter.co.uk) uses a smaller (than the YHDC 100A) one, but a ring-core type, for measuring the diverted energy, and that's into a 5 V Arduino.

If you can disconnect to install the CT, then you have a much wider choice of ring-core ones, which are generally more accurate anyway, as there's no possibility of an air gap.

In the attachment a view of my electrical fuse box, as you can see it's very compact!

This is very common in The Netherlands ;)

Even this one, which I believe Robin uses in his Mk2pvrouter, at 29 mm diameter × 19 mm thick, looks big for that.
http://eppep.com/?action-viewnews-itemid-140364

Wow, that's a tiny panel!  On my house I have a lot more room than you have, but still didn't have enough room for CT's on the main.  So I grouped circuits on the output side of the panel together in one CT like this:

(the circuits were carefully chosen to be from the same phase , which I needed to worry about in the US with split-phase power). 

Maybe you have room to do something like that on the outputs?  Or push back or trim the conduit leaving the panel to expose wires?  Or put CT's around the entire conduit (that would work with plastic conduits)?

Due to the grouping of circuits my dashboard looks like this:

http://data.peakmonitor.com/proto1&id=1

Or put CT's around the entire conduit (that would work with plastic conduits)?

While the conduit would indeed be transparent to the magnetic field from the wires, the fact that hot(s) and neutral(s) are in the same conduit would mean the field is effectively canceled. Short answer, no.

If the conduit contained only hot, or only neutral wires, it would work.

Short answer, no.

You are right, I wasn't thinking! 

The Micro-40 Current Transformer develops @ 40A Max continuous primary current / 26.23mA => 1,05VAC ?

The maximum current per circuit is 16A over here, this is not enough though?

http://www.brultech.com/products/ECM1240/packages/moreInfo/infoMicro40.htm

Current Rating: 40A Max continuous primary current
Output: 26.23mA @ 40A Primary
Accuracy: 3% (Typically 1% on average)
Leads: 1.5m Lead Pair, 300V UL1007
Dielectric Withstanding Voltage (Hi-pot): 2500V/1mA/1min
Dimensions:

ID: 6.7mm (0.26")

OD: 17mm (0.67")

Depth: 7.7mm (0.3")

I am following this thread, because i have exact the same situation as the TS

found this one also:

https://shop.smartenergygroups.com/store/show/segmeter_v25

with a very small current sensor:

https://shop.smartenergygroups.com/store/show/sensor_5mm?tag=3

some pictures...